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Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes/issues, but are citable by Digital Object Identifier (DOI).
A Novel 2-dimensional Multiplex qPCR Assay for Single-Tube Detection of Nine Human Herpesviruses
Yingxue Li, Zhenzhou Wan, Lulu Zuo, Shenwei Li, Honglian Liu, Yingying Ma, Lianqun Zhou, Xia Jin, Yuye Li, Chiyu Zhang
doi: 10.1007/s12250-021-00354-2
Received: 26 September 2020 Accepted: 28 December 2020 Published: 05 March 2021
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Human herpesviruses are double-stranded DNA viruses that are classified into nine species. More than 90% of adults are ever infected with one or more herpesviruses. The symptoms of infection with different herpesviruses are diverse ranging from mild or asymptomatic infections to deadly diseases such as aggressive lymphomas and sarcomas. Timely and accurate detection of herpesvirus infection is critical for clinical management and treatment. In this study, we established a single-tube nonuple qPCR assay for detection of all nine herpesviruses using a 2-D multiplex qPCR method with a house-keeping gene as the internal control. The novel assay can detect and distinguish different herpesviruses with 30 to 300 copies per 25 µL single-tube reaction, and does not cross-react with 20 other human viruses, including DNA and RNA viruses. The robustness of the novel assay was evaluated using 170 clinical samples. The novel assay showed a high consistency (100%) with the single qPCR assay for HHVs detection. The features of simple, rapid, high sensitivity, specificity, and low cost make this assay a high potential to be widely used in clinical diagnosis and patient treatment.
Artesunate and Dihydroartemisinin Inhibit Rabies Virus Replication
Jun Luo, Yue Zhang, Yang Wang, Qing Liu, Jiesen Li, Hongling He, Yongwen Luo, Shile Huang, Xiaofeng Guo
doi: 10.1007/s12250-021-00349-z
Received: 05 August 2020 Accepted: 16 November 2020 Published: 05 March 2021
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Rabies is caused by infection of rabies virus (RABV) and remains a serious threat to the global public health. Except for the requirement for cold chain and high cost of human rabies immune globulin, no small molecule drugs are currently available for clinical treatment of rabies. So, it is of great importance to identify novel compounds that can effectively inhibit RABV infection. Artesunate (ART) and dihydroartemisinin (DHA), two derivatives of artemisinin, are widely used for treatment of malaria in adults and children, showing high safety. In this study, we found that both ART and DHA were able to inhibit RABV replication in host cells at a low concentration (0.1 μmol/L). The antiviral effects of ART and DHA were independent of viral strains and cell lines. Pre-treatment with ART or DHA for 2 h in vitro did not affect the viral replication in host cells, implying that ART and DHA neither reduced the viability of RABV directly nor inhibited the binding and entrance of the virus to host cells. Further studies revealed that ART and DHA inhibited RABV genomic RNA synthesis and viral gene transcription. Treatment with ART or DHA (5 mg/kg) by intramuscular injection improved, to some extent, the survival rate of RABV-challenged mice. Combination treatment with derivatives of artemisinin and mannitol significantly improved the survival rate of RABV-challenged mice. The results suggest that ART and DHA have a great potential to be explored as new anti-rabies agents for treatment of rabies.
Sustainability of SARS-CoV-2 Induced Humoral Immune Responses in COVID-19 Patients from Hospitalization to Convalescence Over Six Months
Yang Zheng, Qing Zhang, Ashaq Ali, Ke Li, Nan Shao, Xiaoli Zhou, Zhiqin Ye, Xiaomin Chen, Shanshan Cao, Jing Cui, Juan Zhou, Dianbing Wang, Baidong Hou, Min Li, Mengmeng Cui, Lihua Deng, Xinyi Sun, Qian Zhang, Qinfang Yang, Yong li, Hui Wang, Yake Lei, Bo Yu, Yegang Cheng, Xiaolin Tong, Dong Men, Xian-En Zhang
doi: 10.1007/s12250-021-00360-4
Received: 24 November 2020 Accepted: 13 January 2021 Published: 04 March 2021
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Understanding the persistence of antibody in convalescent COVID-19 patients may help to answer the current major concerns such as the risk of reinfection, the protection period of vaccination and the possibility of building an active herd immunity. This retrospective cohort study included 172 COVID-19 patients who were hospitalized in Wuhan. A total of 404 serum samples were obtained over six months from hospitalization to convalescence. Antibodies in the specimens were quantitatively analyzed by the capture chemiluminescence immunoassays (CLIA). All patients were positive for the anti-SARS-CoV-2 IgM/IgG at the onset of COVID-19 symptoms, and the IgG antibody persisted in all the patients during the convalescence. However, only approximately 25% of patients can detect the IgM antibodies, IgM against N protein (N-IgM) and receptor binding domain of S protein (RBD-IgM) at the 27th week. The titers of IgM, N-IgM and RBD-IgM reduced to 16.7%, 17.6% and 15.2% of their peak values respectively. In contrast, the titers of IgG, N-IgG and RBD-IgG peaked at 4–5th week and reduced to 85.9%, 62.6% and 87.2% of their peak values respectively at the end of observation. Dynamic behavior of antibodies and their correlation in age, gender and severity groups were investigated. In general, the COVID-19 antibody was sustained at high levels for over six months in most of the convalescent patients. Only a few patients with antibody reducing to an undetectable level which needs further attention. The humoral immune response against SARS-CoV-2 infection in COVID-19 patients exhibits a typical dynamic of acquired immunity.
HRV16 Infection Induces Changes in the Expression of Multiple piRNAs
Jie Li, Xinling Wang, Yanhai Wang, Juan Song, Qinqin Song, Yanbin Wang, Jun Han
doi: 10.1007/s12250-021-00344-4
Received: 20 May 2020 Accepted: 30 October 2020 Published: 22 February 2021
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Human rhinovirus (HRV) is one of the most important cold-causing pathogens in humans. Piwi-interacting RNAs (piRNAs) are a recently discovered class of small non-coding RNAs whose best-understood function is to repress mobile element (ME) activity in animal germline. However, the profile of human/host piRNA during HRV infection is largely unknown. Here we performed high-throughput sequencing of piRNAs from H1-HeLa cells infected with HRV16 at 12 h, 24 h, and 36 h. The results showed that 22,151,664, 24,362,486 and 22,726,546 piRNAs displayed differential expression after HRV16 infection for three time points. A significant differential expression of 21 piRNAs was found in all time points and further verified by RT-qPCR, including 7 known piRNAs and 14 newly found piRNAs. In addition, piRNA prediction was performed on Piano using the SVM algorithm and transposon information. It found that novel_pir78110, novel_pir78107, novel_pir78097, novel_pir78094 and novel_pir76584 are associated with the DNA/hobo of Drosophila, Ac of maize and Tam3 of snapdragon (hAT)-Charlie transposon. The novel_pir97924, novel_pir105705 and novel_pir105700 recognize long interspersed nuclear elements 1 (LINE-1). The novel_pir33182 and novel_pir46604 are related to the long terminal repeat (LTR)/(Endogenous Retrovirus1) ERV1 repetitive element. The novel_pir73855 is related to the LTR/ERVK repetitive element. Both novel_pir70108 and novel_pir70106 are associated with the LTR/ERVL-MaLR repetitive element. The novel_pir15900 is associated with the DNA/hAT-Tip100 repetitive element. Overall, our results indicated that rhinovirus infection could reduce the expression of some piRNAs to facilitate upregulation of LINE-1 transcription or retrotransposons' expression, which is helpful to further explore the mechanism of rhinovirus infection.
Current Status and Challenge of Pseudorabies Virus Infection in China
Lei Tan, Jun Yao, Yadi Yang, Wei Luo, Xiaomin Yuan, Lingchen Yang, Aibing Wang
doi: 10.1007/s12250-020-00340-0
Received: 20 July 2020 Accepted: 17 September 2020 Published: 22 February 2021
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Pseudorabies (PR), also called Aujeszky’s disease, is a highly infectious disease caused by pseudorabies virus (PRV). Without specific host tropism, PRV can infect a wide variety of mammals, including pig, sheep, cattle, etc., thereby causing severe clinical symptoms and acute death. PRV was firstly reported in China in 1950s, while outbreaks of emerging PRV variants have been documented in partial regions since 2011, leading to significant economic losses in swine industry. Although scientists have been devoting to the design of diagnostic approaches and the development of vaccines during the past years, PR remains a vital infectious disease widely prevalent in Chinese pig industry. Especially, its potential threat to human health has also attracted the worldwide attention. In this review, we will provide a summary of current understanding of PRV in China, mainly focusing on PRV history, the existing diagnosis methods, PRV prevalence in pig population and other susceptible mammals, molecular characteristics, and the available vaccines against its infection. Additionally, promising agents including traditional Chinese herbal medicines and novel inhibitors that may be employed to treat this viral infection, are also discussed.
Development of A MERS-CoV Replicon Cell Line for Antiviral Screening
Jing Chen, Bing-Jie Hu, Kai Zhao, Yun Luo, Hao-Feng Lin, Zheng-Li Shi
doi: 10.1007/s12250-020-00341-z
Received: 17 October 2020 Accepted: 23 November 2020 Published: 22 February 2021
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Middle East respiratory syndrome coronavirus (MERS-CoV) is the causative agent of a severe respiratory disease with a high mortality of  ~ 35%. The lack of approved treatments for MERS-CoV infection underscores the need for a user-friendly system for rapid drug screening. In this study, we constructed a MERS-CoV replicon containing the Renilla luciferase (Rluc) reporter gene and a stable luciferase replicon-carrying cell line. Using this cell line, we showed that MERS-CoV replication was inhibited by combined application of lopinavir and ritonavir, indicating that this cell line can be used to screen inhibitors of MERS-CoV replication. Importantly, the MERS-replicon cell line can be used for high-throughput screening of antiviral drugs without the need for live virus handling, providing an effective and safe tool for the discovery of antiviral drugs against MERS-CoV.
Alterations in Phenotypes and Responses of T Cells Within 6 Months of Recovery from COVID-19: A Cohort Study
Bali Zhao, Maohua Zhong, Qingyu Yang, Ke Hong, Jianbo Xia, Xia Li, Ying Liu, Yao-Qing Chen, Jingyi Yang, Chaolin Huang, Huimin Yan
doi: 10.1007/s12250-021-00348-0
Received: 11 October 2020 Accepted: 30 November 2020 Published: 09 February 2021
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The COVID-19 pandemic, caused by the SARS-CoV-2 infection, is a global health crisis. While many patients have clinically recovered, little is known about long-term alterations in T cell responses of COVID-19 convalescents. In this study, T cell responses in peripheral blood mononuclear cells of a long-time COVID-19 clinically recovered (20–26 weeks) cohort (LCR) were measured via flow cytometry and ELISpot. The T cell responses of LCR were comparatively analyzed against an age and sex matched short-time clinically recovered (4–9 weeks) cohort (SCR) and a healthy donor cohort (HD). All volunteers were recruited from Wuhan Jinyintan Hospital, China. Phenotypic analysis showed that activation marker PD-1 expressing on CD4+ T cells of LCR was still significantly lower than that of HD. Functional analysis indicated that frequencies of Tc2, Th2 and Th17 in LCR were comparable to those of HD, but Tc17 was higher than that of HD. In LCR, compared to the HD, there were fewer IFN-γ producing T cells but more IL-2 secreting T cells. In addition, the circulating Tfh cells in LCR were still slightly lower compared to HD, though the subsets composition had recovered. Remarkably, SARS-CoV-2 specific T cell responses in LCR were comparable to that of SCR. Collectively, T cell responses experienced long-term alterations in phenotype and functional potential of LCR cohort. However, after clinical recovery, SARS-CoV-2 specific T cell responses could be sustained at least for six months, which may be helpful in resisting re-infection.
Evaluation of the Safety and Immune Efficacy of Recombinant Human Respiratory Syncytial Virus Strain Long Live Attenuated Vaccine Candidates
Li-Nan Wang, Xiang-Lei Peng, Min Xu, Yuan-Bo Zheng, Yue-Ying Jiao, Jie-Mei Yu, Yuan-Hui Fu, Yan-Peng Zheng, Wu-Yang Zhu, Zhong-Jun Dong, Jin-Sheng He
doi: 10.1007/s12250-021-00345-3
Received: 28 February 2020 Accepted: 18 September 2020 Published: 09 February 2021
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Human respiratory syncytial virus (RSV) infection is the leading cause of lower respiratory tract illness (LRTI), and no vaccine against LRTI has proven to be safe and effective in infants. Our study assessed attenuated recombinant RSVs as vaccine candidates to prevent RSV infection in mice. The constructed recombinant plasmids harbored (5′ to 3′) a T7 promoter, hammerhead ribozyme, RSV Long strain antigenomic cDNA with cold-passaged (cp) mutations or cp combined with temperature-sensitive attenuated mutations from the A2 strain (A2cpts) or further combined with SH gene deletion (A2cptsΔSH), HDV ribozyme (δ), and a T7 terminator. These vectors were subsequently co-transfected with four helper plasmids encoding N, P, L, and M2-1 viral proteins into BHK/T7-9 cells, and the recovered viruses were then passaged in Vero cells. The rescued recombinant RSVs (rRSVs) were named rRSV-Long/A2cp, rRSV-Long/A2cpts, and rRSV-Long/A2cptsΔSH, respectively, and stably passaged in vitro, without reversion to wild type (wt) at sites containing introduced mutations or deletion. Although rRSV-Long/A2cpts and rRSV-Long/A2cptsΔSH displayed temperature-sensitive (ts) phenotype in vitro and in vivo, all rRSVs were significantly attenuated in vivo. Furthermore, BALB/c mice immunized with rRSVs produced Th1-biased immune response, resisted wtRSV infection, and were free from enhanced respiratory disease. We showed that the combination of ΔSH with attenuation (att) mutations of cpts contributed to improving att phenotype, efficacy, and gene stability of rRSV. By successfully introducing att mutations and SH gene deletion into the RSV Long parent and producing three rRSV strains, we have laid an important foundation for the development of RSV live attenuated vaccines.
Human PRV Infection in China: An Alarm to Accelerate Eradication of PRV in Domestic Pigs
Zhenhua Guo, Xin-Xin Chen, Gaiping Zhang
doi: 10.1007/s12250-021-00347-1
Received: 12 October 2020 Accepted: 21 December 2020 Published: 04 February 2021
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Pseudorabies, also known as Aujeszky’s disease, is one of the most economically important viral diseases in pigs and is lethal to other susceptible animals (Ren et al. 2020). The causative agent, pseudorabies virus (PRV), is an enveloped virus with a large double-stranded DNA genome encoding at least 70 proteins (Wong et al. 2019). PRV belongs to the family Herpesviridae, subfamily Alphaherpesvirinae, genus Varicellovirus and infects multiple animals, such as pigs, dogs, cats, rabbits, cattle, sheep, goats, minks, foxes, wolves, lynxes, etc. (He et al. 2019; Laval and Enquist 2020). Pigs are recognized as the natural hosts for the virus, and the PRV infection causes severe neurological symptoms in piglets with almost 100% mortality, respiratory/neurological signs in the nursery, respiratory signs in adult pigs, and reproductive disorders in sows (He et al. 2019; Ren et al. 2020). Most of the other infected non-natural animal hosts die within 24–48 h of disease onset, which is usually characterized by severe pruritus in the head and neck, accompanied by self-mutilation (Laval and Enquist 2020).
ATP1B3 Restricts Hepatitis B Virus Replication Via Reducing the Expression of the Envelope Proteins
Jun Zhang, Tianhang Zheng, Xiaolei Zhou, Hong Wang, Zhaolong Li, Chen Huan, Baisong Zheng, Wenyan Zhang
doi: 10.1007/s12250-021-00346-2
Received: 06 August 2020 Accepted: 23 November 2020 Published: 03 February 2021
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Our recent study reported that ATP1B3 inhibits hepatitis B virus (HBV) replication via inducing NF-κB activation. However, ATP1B3 mutants which were defective in NF-κB activation still maintained the moderate degree of suppression on HBV replication, suggesting that another uncharacterized mechanism is also responsible for ATP1B3-mediated HBV suppression. Here, we demonstrated that ATP1B3 reduced the expression of HBV envelope proteins LHBs, MHBs and SHBs, but had no effect on intracellular HBV DNA, RNA levels as well as HBV promoter activities. Further investigation showed that proteasome inhibitor MG132 rescued ATP1B3-mediated envelope proteins degradation, demonstrating that proteasome-dependent pathway is involved in ATP1B3-induced degradation of envelope proteins. Co-IP showed that ATP1B3 interacts with LHBs and MHBs and induces LHBs and MHBs polyubiquitination. Immunofluorescence colocalization analysis confirmed LHBs and MHBs colocalized with ATP1B3 together. Our work provides important information for targeting ATP1B3 as a potential therapeutic molecule for HBV infection.

Axl Alleviates Neuroinflammation and Delays Japanese Encephalitis Progression in Mice
Zhao-Yang Wang, Zi-Da Zhen, Dong-Ying Fan, Pei-Gang Wang, Jing An
doi: 10.1007/s12250-020-00342-y
Received: 06 July 2020 Accepted: 07 December 2020 Published: 03 February 2021
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Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus, which causes the most commonly diagnosed viral encephalitis named Japanese encephalitis (JE) in the world with an unclear pathogenesis. Axl, a receptor tyrosine kinase from TAM family, plays crucial role in many inflammatory diseases. We have previously discovered that Axl deficiency resulted in more severe body weight loss in mice during JEV infection, which we speculate is due to the anti-inflammatory effect of Axl during JE. Currently, the role of Axl in regulating the neuroinflammation and brain damage during JE has not been investigated yet. In this study, by using Axl deficient and heterozygous control mice, we discovered that Axl deficient mice displayed accelerated JE progression and exacerbated brain damage characterized by increased neural cell death, extended infiltration of inflammatory cells, and enhanced production of pro-inflammatory cytokines, in comparison to control mice. Additionally, consistent with our previous report, Axl deficiency had no impact on the infection and target cell tropism of JEV in brain. Taken together, our results suggest that Axl plays an anti-inflammatory and neuroprotective role during the pathogenesis of JE.

Rearrangement of Actin Cytoskeleton by Zika Virus Infection Facilitates Blood–Testis Barrier Hyperpermeability
Yiwen Nie, Lixia Hui, Moujian Guo, Wei Yang, Rui Huang, Junsen Chen, Xinyue Wen, Meng Zhao, Ying Wu
doi: 10.1007/s12250-020-00343-x
Received: 27 August 2020 Accepted: 24 November 2020 Published: 03 February 2021
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In recent years, various serious diseases caused by Zika virus (ZIKV) have made it impossible to be ignored. Confirmed existence of ZIKV in semen and sexually transmission of ZIKV suggested that it can break the blood–testis barrier (BTB), or Sertoli cell barrier (SCB). However, little is known about the underlying mechanism. In this study, interaction between actin, an important component of the SCB, and ZIKV envelope (E) protein domain Ⅲ (EDⅢ) was inferred from coimmunoprecipitation (Co-IP) liquid chromatography–tandem mass spectrometry (LC–MS/MS) analysis. Confocal microscopy confirmed the role of actin filaments (F-actin) in ZIKV infection, during which part of the stress fibers, the bundles that constituted by paralleled actin filaments, were disrupted and presented in the cell periphery. Colocalization of E and reorganized actin filaments in the cell periphery of transfected Sertoli cells suggests a participation of ZIKV E protein in ZIKV-induced F-actin rearrangement. Perturbation of F-actin by cytochalasin D (CytoD) or Jasplakinolide (Jas) enhanced the infection of ZIKV. More importantly, the transepithelial electrical resistance (TEER) of an in vitro mouse SCB (mSCB) model declined with the progression of ZIKV infection or overexpression of E protein. Co-IP and confocal microscopy analyses revealed that the interaction between F-actin and tight junction protein ZO-1 was reduced after ZIKV infection or E protein overexpression, highlighting the role of E protein in ZIKV-induced disruption of the BTB. We conclude that the interaction between ZIKV E and F-actin leads to the reorganization of F-actin network, thereby compromising BTB integrity.

Systematic Analysis of 42 Autographa Californica Multiple Nucleopolyhedrovirus Genes Identifies An Additional Six Genes Involved in the Production of Infectious Budded Virus
Tong Chen, Xiaoyan Duan, Hengrui Hu, Yu Shang, Yangbo Hu, Fei Deng, Hualin Wang, Manli Wang, Zhihong Hu
doi: 10.1007/s12250-021-00355-1
Received: 30 July 2020 Accepted: 29 December 2020 Published: 28 January 2021
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Baculoviruses have been widely used as a vector for expressing foreign genes. Among numerous baculoviruses, Autographa californica multiple nucleopolyhedrovirus (AcMNPV) is the most frequently used and it encodes 155 open reading frames (ORFs). Here, we systematically investigated the impact of 42 genes of AcMNPV on the production of infectious budded viruses (BVs) by constructing gene-knockout bacmids and subsequently conducting transfection and infection assays. The results showed that among the 39 functionally unverified genes and 3 recently reported genes, 36 are dispensable for infectious BV production, as the one-step growth curves of the gene-knockout viruses were not significantly different from those of the parental virus. Three genes (ac62, ac82 and ac106/107) are essential for infectious BV production, as deletions thereof resulted in complete loss of infectivity while the repaired viruses showed no significant difference in comparison to the parental virus. In addition, three genes (ac13, ac51 and ac120) are important but not essential for infectious BV production, as gene-knockout viruses produced significantly lower BV levels than that of the parental virus or repaired viruses. We then grouped the 155 AcMNPV genes into three categories (Dispensable, Essential, or Important for infectious BV production). Based on our results and previous publications, we constructed a schematic diagram of a potential mini-genome of AcMNPV, which contains only essential and important genes. The results shed light on our understanding of functional genomics of baculoviruses and provide fundamental information for future engineering of baculovirus expression system.
Role of Intracellular Distribution of Feline and Bovine SAMHD1 Proteins in Lentiviral Restriction
Chu Wang, Lina Meng, Jialin Wang, Kaikai Zhang, Sizhu Duan, Pengyu Ren, Yingzhe Wei, Xinyu Fu, Bin Yu, Jiaxin Wu, Xianghui Yu
doi: 10.1007/s12250-021-00351-5
Received: 03 August 2020 Accepted: 28 December 2020 Published: 28 January 2021
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Human SAMHD1 (hSAM) restricts lentiviruses at the reverse transcription step through its dNTP triphosphohydrolase (dNTPase) activity. Besides humans, several mammalian species such as cats and cows that carry their own lentiviruses also express SAMHD1. However, the intracellular distribution of feline and bovine SAMHD1 (fSAM and bSAM) and its significance in their lentiviral restriction function is not known. Here, we demonstrated that fSAM and bSAM were both predominantly localized to the nucleus and nuclear localization signal (11KRPR14)-deleted fSAM and bSAM relocalized to the cytoplasm. Both cytoplasmic fSAM and bSAM retained the antiviral function against different lentiviruses and cytoplasmic fSAM could restrict Vpx-encoding SIV and HIV-2 more efficiently than its wild-type (WT) protein as cytoplasmic hSAM. Further investigation revealed that cytoplasmic fSAM was resistant to Vpx-induced degradation like cytoplasmic hSAM, while cytoplasmic bSAM was not, but they all demonstrated the same in vitro dNTPase activity and all could interact with Vpx as their WT proteins, indicating that cytoplasmic hSAM and fSAM can suppress more SIV and HIV-2 by being less sensitive to Vpx-mediated degradation. Our results suggested that fSAM- and bSAM-mediated lentiviral restriction does not require their nuclear localization and that fSAM shares more common features with hSAM. These findings may provide insights for the establishment of alternative animal models to study SAMHD1 in vivo.
African Swine Fever Virus MGF-110-9L-deficient Mutant Has Attenuated Virulence in Pigs
Dan Li, Yinguang Liu, Xiaolan Qi, Yuan Wen, Pan Li, Zhao Ma, Yongjie Liu, Haixue Zheng, Zhijie Liu
doi: 10.1007/s12250-021-00350-6
Received: 18 July 2020 Accepted: 17 December 2020 Published: 28 January 2021
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African swine fever virus (ASFV) is the etiological agent of African swine fever (ASF), an often lethal disease in domestic and wild pigs. ASF represents a major threat to the swine industry worldwide. Currently, no commercial vaccine is available because of the complexity of ASFV or biosecurity concerns. Live attenuated viruses that are naturally isolated or genetically manipulated have demonstrated reliable protection against homologous ASFV strain challenge. In the present study, a mutant ASFV strain with the deletion of ASFV MGF-110-9L (ASFV-Δ9L) was generated from a highly virulent ASFV CN/GS/2018 parental strain, a genotype II ASFV. Relative to the parental ASFV isolate, deletion of the MGF-110-9L gene significantly decreased the ability of ASFV-Δ9L to replicate in vitro in primary swine macrophage cell cultures. The majority of animals inoculated intramuscularly with a low dose of ASFV-Δ9L (10 HAD50) remained clinically normal during the 21-day observational period. Three of five ASFV-Δ9L-infected animals displayed low viremia titers and low virus shedding and developed a strong virus-specific antibody response, indicating partial attenuation of the ASFV-Δ9L strain in pigs. The findings imply the potential usefulness of the ASFV-Δ9L strain for further development of ASF control measures.
Porcine Picornavirus 3C Protease Degrades PRDX6 to Impair PRDX6-mediated Antiviral Function
Congcong Wang, Huanhuan Feng, Xiangle Zhang, Kangli Li, Fan Yang, Weijun Cao, Huisheng Liu, Lili Gao, Zhaoning Xue, Xiangtao Liu, Zixiang Zhu, Haixue Zheng
doi: 10.1007/s12250-021-00352-4
Received: 30 September 2020 Accepted: 17 December 2020 Published: 28 January 2021
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Peroxiredoxin-6 (PRDX6) is an antioxidant enzyme with both the activities of peroxidase and phospholipase A2 (PLA2), which is involved in regulation of many cellular reactions. However, the function of PRDX6 during virus infection remains unknown. In this study, we found that the abundance of PRDX6 protein was dramatically decreased in foot-and-mouth disease virus (FMDV) infected cells. Overexpression of PRDX6 inhibited FMDV replication. In contrast, knockdown of PRDX6 expression promoted FMDV replication, suggesting an antiviral role of PRDX6. To explore whether the activity of peroxidase and PLA2 was associated with PRDX6-mediated antiviral function, a specific inhibitor of PLA2 (MJ33) and a specific inhibitor of peroxidase activity (mercaptosuccinate) were used to treat the cells before FMDV infection. The results showed that incubation of MJ33 but not mercaptosuccinate promoted FMDV replication. Meanwhile, overexpression of PRDX6 slightly enhanced type I interferon signaling. We further determined that the viral 3Cpro was responsible for degradation of PRDX6, and 3Cpro-induced reduction of PRDX6 was independent of the proteasome, lysosome, and caspase pathways. The protease activity of 3Cpro was required for induction of PRDX6 reduction. Besides, PRDX6 suppressed the replication of another porcine picornavirus Senecavirus A (SVA), and the 3Cpro of SVA induced the reduction of PRDX6 through its proteolytic activity as well. Together, our results suggested that PRDX6 plays an important antiviral role during porcine picornavirus infection, and the viral 3Cpro induces the degradation of PRDX6 to overcome PRDX6-mediated antiviral function.
Autographa californica Multiple Nucleopolyhedrovirus orf13 is Required for Efficient Nuclear Egress of Nucleocapsids
Xingang Chen, Xiaoqin Yang, Chengfeng Lei, Fujun Qin, Xiulian Sun, Jia Hu
doi: 10.1007/s12250-021-00353-3
Received: 20 October 2020 Accepted: 18 December 2020 Published: 28 January 2021
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Autographa californica multiple nucleopolyhedrovirus (AcMNPV) orf13 (ac13) is a conserved gene in all sequenced alphabaculoviruses. However, its function in the viral life cycle remains unknown. In this study, we found that ac13 was a late gene and that the encoded protein, bearing a putative nuclear localization signal motif, colocalized with the nuclear lamina. Deletion of ac13 did not affect viral genome replication, nucleocapsid assembly or occlusion body (OB) formation, but reduced virion budding from infected cells by approximately 400-fold compared with the wild-type virus. Deletion of ac13 substantially impaired the egress of nucleocapsids from the nucleus to the cytoplasm, while the OB morphogenesis was unaffected. Taken together, our results indicated that ac13 was required for efficient nuclear egress of nucleocapsids during virion budding, but was dispensable for OB formation.
Visualization of the Oncolytic Alphavirus M1 Life Cycle in Cancer Cells
Jia Dan, Lin Nie, Xudong Jia, Cuiying Xu, Jing Cai, Yuan Lin, Jun Hu, Wenbo Zhu, Yinyin Li, Dong Chen, Ying Liu, Cheng Hu, Guangmei Yan, Jiankai Liang, Qinfen Zhang
doi: 10.1007/s12250-020-00339-7
Received: 11 July 2020 Accepted: 26 October 2020 Published: 22 January 2021
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Oncolytic alphavirus M1 has been shown to selectively target and kill cancer cells, but cytopathic morphologies induced by M1 virus and the life cycle of the M1 strain in cancer cells remain unclear. Here, we study the key stages of M1 virus infection and replication in the M1 virus-sensitive HepG2 liver cancer cell line by transmission electron microscopy, specifically examining viral entry, assembly, maturation and release. We found that M1 virus induces vacuolization of cancer cells during infection and ultimately nuclear marginalization, a typical indicator of apoptosis. Specifically, our results suggest that the endoplasmic reticulum participates in the assembly of nucleocapsids. In the early and late stage of infection, three kinds of special cytopathic vacuoles are formed and appear to be involved in the replication, maturation and release of the virus. Taken together, our data displayed the process of M1 virus infection of tumor cells and provide the structural basis for the study of M1 virus-host interactions.

Conferring Resistance to Plant RNA Viruses with the CRISPR/CasRx System
Yongsen Cao, Huanbin Zhou, Xueping Zhou, Fangfang Li
doi: 10.1007/s12250-020-00338-8
Received: 19 August 2020 Accepted: 21 November 2020 Published: 18 January 2021
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Laboratory-based Surveillance and Clinical Profile of Sporadic HEV Infection in Shanghai, China
Jie Lu, Qing Li, Jiayuan Jiang, Ziqiang Li, Peiyun Wang, Zike Sheng, Rongtao Lai, Huijuan Zhou, Wei Cai, Hui Wang, Qing Guo, Honglian Gui, Qing Xie
doi: 10.1007/s12250-020-00336-w
Received: 17 September 2020 Accepted: 30 October 2020 Published: 12 January 2021
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The study aimed to describe the epidemiological, virological and clinical features of sporadic HEV infection in eastern China. A total of 6112 patient sera were tested for anti-HEV IgG or anti-HEV IgM during one consecutive year (between August 2018 and July 2019). HEV RNA presence was evaluated by RT-PCR and HEV sequences were phylogenetically analyzed. Clinical features of confirmed HEV-infected patients were delineated. The sero-positivity rate of anti-HEV IgG maintained stable around 40%, while an obvious winter spike of anti-HEV IgM prevalence was observed. A total of 111 patients were confirmed of HEV viremia by molecular diagnosis. Subtype 4d was predominant. Phylogenetic analyses suggest that certain strains circulate across species and around the country. Subjects with confirmed current HEV infection had a high median age (58 years) and males were predominant (62.2%). Most patients presented with jaundice (75.7%) and anorexia (68.0%). Significantly elevated levels of liver enzymes and bilirubin were observed. Remarkably, the baseline bilirubin level was positively correlated with illness severity. Pre-existing HBV carriage may deteriorate illness. The clinical burden caused by locally acquired HEV infection is increasing. Surveillance should be enforced especially during the transition period from winter to spring. Patients with higher level of bilirubin at disease onset had slower recovery from HEV infection.

Development of A Super-Sensitive Diagnostic Method for African Swine Fever Using CRISPR Techniques
Meishen Ren, Hong Mei, Ming Zhou, Zhen F. Fu, Heyou Han, Dingren Bi, Fuhu Peng, Ling Zhao
doi: 10.1007/s12250-020-00323-1
Received: 12 May 2020 Accepted: 20 October 2020 Published: 07 January 2021
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African swine fever (ASF) is an infectious disease caused by African swine fever virus (ASFV) with clinical symptoms of high fever, hemorrhages and high mortality rate, posing a threat to the global swine industry and food security. Quarantine and control of ASFV is crucial for preventing swine industry from ASFV infection. In this study, a recombinase polymerase amplification (RPA)-CRISPR-based nucleic acid detection method was developed for diagnosing ASF. As a highly sensitive method, RPA-CRISPR can detect even a single copy of ASFV plasmid and genomic DNA by determining fluorescence signal induced by collateral cleavage of CRISPR-lwCas13a (previously known as C2c2) through quantitative real-time PCR (qPCR) and has the same or even higher sensitivity than the traditional qPCR method. A lateral flow strip was developed and used in combination with RPA-CRISPR for ASFV detection with the same level of sensitivity of TaqMan qPCR. Likewise, RPA-CRISPR is capable of distinguishing ASFV genomic DNA from viral DNA/RNA of other porcine viruses without any cross-reactivity. This diagnostic method is also available for diagnosing ASFV clinical DNA samples with coincidence rate of 100% for both ASFV positive and negative samples. RPA-CRISPR has great potential for clinical quarantine of ASFV in swine industry and food security.
Genetic Analysis of Human Adenovirus Type 7 Strains Circulating in Different Parts of China
Yali Duan, Changchong Li, Li Deng, Shuhua An, Yun Zhu, Wei Wang, Meng Zhang, Li liXu, Baoping Xu, Xiangpeng Chen, Zhengde Xie
doi: 10.1007/s12250-020-00334-y
Received: 24 April 2020 Accepted: 10 October 2020 Published: 05 January 2021
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To investigate the molecular epidemiology and genetic variation of human adenovirus type 7 (HAdV-7) in children with acute respiratory infections (ARI) in China. HAdV-7-positive respiratory samples collected from children with ARI in Beijing, Shijiazhuang, Wenzhou and Guangzhou from 2014–2018 were selected for gene amplification and sequence analysis. Fifty-seven HAdV-7 clinical strains with hexon, penton base and fiber gene sequences were obtained. Meanwhile 17 strains were selected randomly from different cities for whole genome sequencing. Phylogenetic and variation analyses were performed based on the obtained sequences, HAdV-7 prototype strain Gomen (AY594255), vaccine strains (AY495969 and AY594256) and representative sequences of strains. The phylogenetic trees constructed based on whole genome sequences, major capsid protein genes (hexon, penton base and fiber) and the early genes (E1, E2, E3 and E4) were not completely consistent. The HAdV-7 strains obtained in this study always clustered with most of the circulating strains worldwide from the 1980s to the present. Compared with the HAdV-7 prototype strain Gomen (AY594255), some amino acid mutations in loop1 and loop2 of hexon and the RGD loop region of the penton base gene were observed. Recombination analysis showed that partial regions of 55 kDa protein and 100 kDa hexon-assembly associated protein genes among all HAdV-7 strains in this study were from HAdV-16 and HAdV-3, respectively. Our study demonstrated the molecular evolution characteristics of HAdV-7 strains circulating in China and provided basic reference data for the prevention, control and vaccine development of HAdV-7.
Foot-and-Mouth Disease Virus Inhibits RIP2 Protein Expression to Promote Viral Replication
Huisheng Liu, Qiao Xue, Zixiang Zhu, Fan Yang, Weijun Cao, Xiangtao Liu, Haixue Zheng
doi: 10.1007/s12250-020-00322-2
Received: 10 July 2020 Accepted: 17 September 2020 Published: 05 January 2021
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Receptors interaction protein 2 (RIP2) is a specific adaptor molecule in the downstream of NOD2. The role of RIP2 during foot-and-mouth disease virus (FMDV) infection remains unknown. Here, our results showed that RIP2 inhibited FMDV replication and played an important role in the activation of IFN-β and NF-κB signal pathways during FMDV infection. FMDV infection triggered RIP2 transcription, while it reduced the expression of RIP2 protein. Detailed analysis showed that FMDV 2B, 2C, 3Cpro, and Lpro proteins were responsible for inducing the reduction of RIP2 protein. 3Cpro and Lpro are viral proteinases that can induce the cleavage or reduction of many host proteins and block host protein synthesis. The carboxyl terminal 105-C114 and 135-C144 regions of 2B were essential for reduction of RIP2. Our results also showed that the N terminal 1-61 region of 2C were essential for the reduction of RIP2. The 2C-induced reduction of RIP2 was dependent on inducing the reduction of poly(A)-binding protein 1 (PABPC1). The interaction between RIP2 and 2C was observed in the context of viral infection, and the residues 1-61 were required for the interaction. These data clarify novel mechanisms of reduction of RIP2 mediated by FMDV.
Cell Cycle Arrest Protein CDKN2C Is Not an HBV Host Factor
Guiwen Guan, Liwei Zheng, Jingyuan Xi, Xingwen Yang, Xiangmei Chen, Fengmin Lu
doi: 10.1007/s12250-020-00337-9
Received: 27 July 2020 Accepted: 16 November 2020 Published: 05 January 2021
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Phylogenetic Analysis of the Dengue Virus Strains Causing the 2019 Dengue Fever Outbreak in Hainan, China
Jiang Du, Liyuan Zhang, Xiaoyuan Hu, Ruoyan Peng, Gaoyu Wang, Yi Huang, Wenqi Wang, Kunliang Wu, Qiang Wang, Haoxiang Su, Fan Yang, Yun Zhang, Chuanning Tang, Xiuji Cui, Lina Niu, Gang Lu, Meifang Xiao, Yongguo Du, Feifei Yin
doi: 10.1007/s12250-020-00335-x
Received: 16 August 2020 Accepted: 03 December 2020 Published: 05 January 2021
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Dengue virus is an arthropod-borne pathogen that is transmitted to humans primarily by Aedes spp. mosquitos, causing the acute infectious disease, dengue fever (DF). Until 2019, no dengue outbreak had been reported in Hainan Province for over 20 years. However, in early September of 2019, an increasing number of infected cases appeared and the DF outbreak lasted for over one month in Haikou City, Hainan Province. In our study, we collected 97 plasma samples from DF patients at three hospitals, as well as 1585 mosquito larvae samples from puddles in different areas of Haikou. There were 49 (50.5%) plasma samples found to be strongly positive and 9 (9.3%) plasma samples were weakly positive against the NS1 antigen. We discovered DENV both in the patient's plasma samples and mosquito larvae samples, and isolated the virus from C6/36 cells inoculated with the acute phase serum of patients. Phylogenetic analysis revealed that the new strains were the most closely related to the epidemic strain in the southern regions of China, belonging to lineage Ⅳ, genotype Ⅰ, DENV-1. Compared to the seven closest strains from neighboring countries and provinces, a total of 18 amino acid mutations occurred in the coding sequences (CDS) of the new isolated strain, DENV1 HMU-HKU-2. Our data shows that dengue virus is re-emerged in Hainan, and pose new threats for public health. Thus regular molecular epidemiological surveillance is necessary for control and prevention of DENV transmission.
Metagenomic Profiling of Viruses Associated with Rhipicephalus microplus Ticks in Yunnan Province, China
Junming Shi, Shu Shen, Hui Wu, Yunzhi Zhang, Fei Deng
doi: 10.1007/s12250-020-00319-x
Received: 22 August 2020 Accepted: 10 October 2020 Published: 05 January 2021
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Ticks are well known as vectors of many viruses which usually do great harm to human and animal health. Yunnan Province, widely covered by flourishing vegetation and mainly relying on farming husbandry, is abundant with Rhipicephalus microplus ticks. Therefore, it is of great significance to characterize the viral profile present in R. microplus parasitizing on cattle in Yunnan Province. In this study, a total of 7387 R. microplus ticks were collected from cattle and buffalo in the northwest and southeast areas of Yunnan Province from 2015 to 2017. We investigated the virome of R. microplus using next-generation sequencing (NGS) and the prevalence of important identified viruses among tick groups by RT-PCR. It revealed the presence of diverse virus concerning chu-, rhabdo-, phlebo-, flavi- and parvo- viruses in Yunnan. These viruses consist of single-stranded, circular and segmented sense RNAs, showing a greatly diversity in genomic organization. Furthermore, continuous epidemiological survey among ticks reveals broad prevalence of three viruses (Yunnan mivirus 1, Wuhan tick vrius 1 and YN tick-associated phlebovirus 1) and two possible prevalent viruses including a flavivirus-like segmented virus (Jingmen tick virus) and a bovine hokovirus 2 in Yunnan. Serological investigation among cattle indicates that these identified viruses may be infectious to cattle and can elicit corresponding antibody. Our findings on R. microplus-associated viral community will contribute to the prevention of viral disease and tracking the viral evolution. Further analysis is needed to better elucidate the pathogenicity and natural circulation of these viruses.
Herpesviruses and the Type Ⅲ Interferon System
Yue Yin, Herman W. Favoreel
doi: 10.1007/s12250-020-00330-2
Received: 09 September 2020 Accepted: 27 October 2020 Published: 05 January 2021
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Type Ⅲ interferons (IFNs) represent the most recently discovered group of IFNs. Together with type Ⅰ IFNs (e.g. IFN-α/β), type Ⅲ IFNs (IFN-λ) are produced as part of the innate immune response to virus infection, and elicit an anti-viral state by inducing expression of interferon stimulated genes (ISGs). It was initially thought that type Ⅰ IFNs and type Ⅲ IFNs perform largely redundant functions. However, it has become evident that type Ⅲ IFNs particularly play a major role in antiviral protection of mucosal epithelial barriers, thereby serving an important role in the first-line defense against virus infection and invasion at contact areas with the outside world, versus the generally more broad, potent and systemic antiviral effects of type Ⅰ IFNs. Herpesviruseses are large DNA viruses, which enter their host via mucosal surfaces and establish lifelong, latent infections. Despite the importance of mucosal epithelial cells in the pathogenesis of herpesviruses, our current knowledge on the interaction of herpesviruses with type Ⅲ IFN is limited and largely restricted to studies on the alphaherpesvirus herpes simplex virus (HSV). This review summarizes the current understanding about the role of IFN-λ in the immune response against herpesvirus infections.
Monocyte/Macrophage-Mediated Innate Immunity in HIV-1 Infection: From Early Response to Late Dysregulation and Links to Cardiovascular Diseases Onset
Eman Teer, Danzil E. Joseph, Richard H. Glashoff, M.Faadiel Essop
doi: 10.1007/s12250-020-00332-0
Received: 29 July 2020 Accepted: 26 October 2020 Published: 05 January 2021
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Although monocytes and macrophages are key mediators of the innate immune system, the focus has largely been on the role of the adaptive immune system in the context of human immunodeficiency virus (HIV) infection. Thus more attention and research work regarding the innate immune system—especially the role of monocytes and macrophages during early HIV-1 infection—is required. Blood monocytes and tissue macrophages are both susceptible targets of HIV-1 infection, and the early host response can determine whether the nature of the infection becomes pathogenic or not. For example, monocytes and macrophages can contribute to the HIV reservoir and viral persistence, and influence the initiation/extension of immune activation and chronic inflammation. Here the expansion of monocyte subsets (classical, intermediate and non-classical) provide an increased understanding of the crucial role they play in terms of chronic inflammation and also by increasing the risk of coagulation during HIV-1 infection. This review discusses the role of monocytes and macrophages during HIV-1 pathogenesis, starting from the early response to late dysregulation that occurs as a result of persistent immune activation and chronic inflammation. Such changes are also linked to downstream targets such as increased coagulation and the onset of cardiovascular diseases.
Development of Improved Mumps Vaccine Candidates by Mutating Viral mRNA Cap Methyltransferase Sites in the Large Polymerase Protein
Xiaoqiang Hao, Yilong Wang, Mengying Zhu, Dongming Zhou, Rongxian Liu, Bin Wang, Yao-Wei Huang, Zhengyan Zhao
doi: 10.1007/s12250-020-00326-y
Received: 26 July 2020 Accepted: 20 October 2020 Published: 07 December 2020
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Although a live attenuated vaccine is available for controlling mumps virus (MuV), mumps still outbreaks frequently worldwide. The attenuated MuV vaccine strain S79 is widely used in mumps vaccination in China, but still with many shortcomings, among which the most prominent are the side effects and decreased immunity. Therefore, there is a need to further improve the safety and efficacy of the current MuV vaccine. In the present study, we further attenuated MuV S79 vaccine strain by inhibiting viral mRNA methyltransferase (MTase). We generated a panel of eight recombinant MuVs (rMuVs) carrying mutations in the MTase catalytic site or S-adenosylmethionine (SAM) binding site in the large (L) polymerase protein. These rMuVs are genetically stable and seven rMuVs are more attenuated in replication in cell culture and five rMuVs are more attenuated in replication in lungs of cotton rats compared with the parental vaccine strain S79. Importantly, cotton rats vaccinated with these seven rMuV mutants produced high levels of serum neutralizing antibodies and were completely protected against challenge with a wild-type MuV strain (genotype F). Therefore, our results demonstrate that alteration in the MTase catalytic site or SAM binding site in MuV L protein improves the safety or the immunogenicity of the MuV vaccine and thus mRNA cap MTase may be an effective target for the development of new vaccine candidates for MuV.
Beta- and Novel Delta-Coronaviruses Are Identified from Wild Animals in the Qinghai-Tibetan Plateau, China
Wentao Zhu, Jing Yang, Shan Lu, Ruiting Lan, Dong Jin, Xue-lian Luo, Ji Pu, Shusheng Wu, Jianguo Xu
doi: 10.1007/s12250-020-00325-z
Received: 03 August 2020 Accepted: 27 September 2020 Published: 01 December 2020
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Outbreaks of severe virus infections with the potential to cause global pandemics are increasingly concerning. One type of those commonly emerging and re-emerging pathogens are coronaviruses (SARS-CoV, MERS-CoV and SARS-CoV-2). Wild animals are hosts of different coronaviruses with the potential risk of cross-species transmission. However, little is known about the reservoir and host of coronaviruses in wild animals in Qinghai Province, where has the greatest biodiversity among the world's high-altitude regions. Here, from the next-generation sequencing data, we obtained a known beta-coronavirus (beta-CoV) genome and a novel delta-coronavirus (delta-CoV) genome from faecal samples of 29 marmots, 50 rats and 25 birds in Yushu Tibetan Autonomous Prefecture, Qinghai Province, China in July 2019. According to the phylogenetic analysis, the beta-CoV shared high nucleotide identity with Coronavirus HKU24. Although the novel delta-CoV (MtCoV) was closely related to Sparrow deltacoronavirus ISU42824, the protein spike of the novel delta-CoV showed highest amino acid identity to Sparrow coronavirus HKU17 (73.1%). Interestingly, our results identified a novel host (Montifringilla taczanowskii) for the novel delta-CoV and the potential cross-species transmission. The most recent common ancestor (tMRCA) of MtCoVs along with other closest members of the species of Coronavirus HKU15 was estimated to be 289 years ago. Thus, this study increases our understanding of the genetic diversity of beta-CoVs and delta-CoVs, and also provides a new perspective of the coronavirus hosts.
Tumor Necrosis Factor α Reduces SNAP29 Dependent Autolysosome Formation to Increase Prion Protein Level and Promote Tumor Cell Migration
Huan Li, Ren Wang, Ze Yu, Run Shi, Jie Zhang, Shanshan Gao, Ming Shao, Shuzhong Cui, Zhenxing Gao, Jiang Xu, Man-Sun Sy, Chaoyang Li
doi: 10.1007/s12250-020-00320-4
Received: 12 August 2020 Accepted: 10 October 2020 Published: 25 November 2020
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Tumor Necrosis Factor α (TNFα) is best known as a mediator of inflammation and immunity, and also plays important roles in tumor biology. However, the role of TNFα in tumor biology is complex and not completely understood. In a human melanoma cell line, M2, and a lung carcinoma cell line, A549, TNFα up-regulates prion protein (PrP) level, and promotes tumor cell migration in a PrP dependent manner. Silencing PRNP abrogates TNFα induced tumor cell migration; this phenotype is reversed when PRNP is re-introduced. Treatment with TNFα activates nuclear factor kappa B (NF-кB) signaling, which then mitigates autophagy by reducing the expression of Forkhead Box P3 (FOXP3). Down regulation of FOXP3 reduces the transcription of synaptosome associated protein 29 (SNAP29), which is essential in the fusion of autophagosome and lysosome creating autolysosome. FOXP3 being a bona fide transcription factor for SNAP29 is confirmed in a promoter binding assay. Accordingly, silencing SNAP29 in these cell lines also up-regulates PrP, and promotes tumor cell migration without TNFα treatment. But, when SNAP29 or FOXP3 is silenced in these cells, they are no longer respond to TNFα. Thus, a reduction in autophagy is the underlying mechanism by which expression of PrP is up-regulated, and tumor cell migration is enhanced upon TNFα treatment. Disrupting the TNFα-NF-кB-FOXP3-SNAP29 signaling axis may provide a therapeutic approach to mitigate tumor cell migration.
SOX5 Regulates Cell Proliferation, Apoptosis, Migration and Invasion in KSHV-Infected Cells
Wu-Mei Yuan, Ya-Ge Fan, Meng Cui, Ting Luo, Ya-E Wang, Zhan-Jun Shu, Juan Zhao, Jun Zheng, Yan Zeng
doi: 10.1007/s12250-020-00313-3
Received: 01 July 2020 Accepted: 16 September 2020 Published: 24 November 2020
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Kaposi's sarcoma (KS) originates from vascular endothelial cells, with KS-associated herpesvirus (KSHV) as the etiological agent. SRY-box transcription factor 5 (SOX5) plays different roles in various types of cancer, although its role in KS remains poorly understood. In this study, we identified the role of SOX5 in KS tissues and KSHV-infected cells and elucidated the molecular mechanism. Thirty-two KS patients were enrolled in this study. Measurement of SOX5 mRNA and protein levels in human KS tissues and adjacent control tissues revealed lower levels in KS tissues, with KS patients having higher SOX5 level in the early stages of the disease compared to the later stages. And SOX5 mRNA and protein was also lower in KSHV-infected cells (iSLK-219 and iSLK-BAC) than normal cells (iSLK-Puro). Additionally, SOX5 overexpression inhibited cell proliferation and promoted apoptosis and decreased KSHV-infected cell migration and invasion. Moreover, we found that SOX5 overexpression suppressed the epithelial-to-mesenchymal transition of KSHV-infected cells. These results suggest SOX5 is a suppressor factor during KS development and a potential target for KS treatment.
Generation of A Stable GFP-reporter Zika Virus System for High-throughput Screening of Zika Virus Inhibitors
Jing-Wei Zhang, Han Wang, Jing Liu, Le Ma, Rong-Hong Hua, Zhi-Gao Bu
doi: 10.1007/s12250-020-00316-0
Received: 31 July 2020 Accepted: 18 September 2020 Published: 24 November 2020
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Zika virus (ZIKV) is associated with severe birth defects and Guillain-Barré syndrome and no approved vaccines or specific therapies to combat ZIKV infection are currently available. To accelerate anti-ZIKV therapeutics research, we developed a stable ZIKV GFP-reporter virus system with considerably improved GFP visibility and stability. In this system a BHK-21 cell line expressing DC-SIGNR was established to facilitate the proliferation of GFP-reporter ZIKV. Using this reporter virus system, we established a high-throughput screening assay and screened a selected plant-sourced compounds library for their ability to block ZIKV infection. More than 31 out of 974 tested compounds effectively decreased ZIKV reporter infection. Four selected compounds, homoharringtonine (HHT), bruceine D (BD), dihydroartemisinin (DHA) and digitonin (DGT), were further validated to inhibit wild-type ZIKV infection in cells of BHK-21 and human cell line A549. The FDA-approved chronic myeloid leukemia treatment drug HHT and BD were identified as broad-spectrum flavivirus inhibitors. DHA, another FDA-approved antimalarial drug effectively inhibited ZIKV infection in BHK-21 cells. HHT, BD and DHA inhibited ZIKV infection at a post-entry stage. Digitonin was found to have inhibitory activity in the early stage of viral infection. Our research provides an efficient high-throughput screening assay for ZIKV inhibitors. The active compounds identified in this study represent potential therapies for the treatment of ZIKV infection.
Broad Cell Tropism of SADS-CoV In Vitro Implies Its Potential Cross-Species Infection Risk
Yun Luo, Ying Chen, Rong Geng, Bei Li, Jing Chen, Kai Zhao, Xiao-Shuang Zheng, Wei Zhang, Peng Zhou, Xing-Lou Yang, Zheng-Li Shi
doi: 10.1007/s12250-020-00321-3
Received: 15 July 2020 Accepted: 26 October 2020 Published: 17 November 2020
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Sumoylation of Human Parainfluenza Virus Type 3 Phosphoprotein Correlates with A Reduction in Viral Replication
Qi Cheng, Wenjing Huai, Xiaoyan Wu, Mingzhou Chen
doi: 10.1007/s12250-020-00314-2
Received: 11 September 2020 Accepted: 29 September 2020 Published: 16 November 2020
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Human parainfluenza virus type 3 (HPIV3), a member of the Paramyxoviridae family, can cause lower respiratory disease in infants and young children. The phosphoprotein (P) of HPIV3 is an essential cofactor of the viral RNA-dependent RNA polymerase large protein (L). P connects nucleocapsid protein (N) with L to initiate genome transcription and replication. Sumoylation influences many important pathways of the target proteins, and many viral proteins are also themselves sumoylated. In this study, we found that the P of HPIV3 could be sumoylated, and mutation of K492 and K532 to arginine (PK492R/K532R) failed to be sumoylated within P, which enhances HPIV3 minigenome activity. Biochemical studies showed that PK492R/K532R had no effect on its interactions with N, formation of homo-tetramers and formation of inclusion bodies. Finally, we found that incorporation of K492R/K532R into a recombinant HPIV3 (rHPIV3-PK492R/K532R) increased viral production in culture cells, suggesting that sumoylation attenuates functions of P and down-regulates viral replication.
Piperlongumine Inhibits Zika Virus Replication In vitro and Promotes Up-Regulation of HO-1 Expression, Suggesting An Implication of Oxidative Stress
Weizhi Lu, Linjuan Shi, Jing Gao, Huimin Zhu, Ying Hua, Jintai Cai, Xianbo Wu, Chengsong Wan, Wei Zhao, Zhang Bao
doi: 10.1007/s12250-020-00310-6
Received: 16 April 2020 Accepted: 25 August 2020 Published: 13 November 2020
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Owing to the widespread distribution of mosquitoes capable of transmitting Zika virus, lack of clinical vaccines and treatments, and poor immunity of populations to new infectious diseases, Zika virus has become a global public health concern. Recent studies have found that Zika virus can continuously infect human brain microvascular endothelial cells. These cells are the primary components of the bloodɃbrain barrier of the cerebral cortex, and further infection of brain tissue may cause severe damage such as encephalitis and fetal pituitary disease. The present study found that a biologically active base, piperlongumine (PL), inhibited Zika virus replication in human brain microvascular endothelial cells, Vero cells, and human umbilical vein endothelial cells. PL also significantly increased heme oxygenase-1 (HO-1) gene expression, while silencing HO-1 expression and using the reactive oxygen species scavenger, N-acetylcysteine, attenuated the inhibitory effect of PL on Zika virus replication. These results suggest that PL induces oxidative stress in cells by increasing reactive oxygen species. This, in turn, induces an increase in HO-1 expression, thereby inhibiting Zika virus replication. These findings provide novel clues for drug research on the prevention and treatment of Zika virus.
Suppression of HIV-1 Integration by Targeting HIV-1 Integrase for Degradation with A Chimeric Ubiquitin Ligase
Zuopeng Zhang, Sen Yuan, Shuting Xu, Deyin Guo, Lang Chen, Wei Hou, Min Wang
doi: 10.1007/s12250-020-00311-5
Received: 14 March 2020 Accepted: 14 September 2020 Published: 13 November 2020
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Human immunodeficiency virus (HIV) attacks human immune system and causes life-threatening acquired immune deficiency syndrome (AIDS). Treatment with combination antiretroviral therapy (cART) could inhibit virus growth and slow progression of the disease, however, at the same time posing various adverse effects. Host ubiquitin-proteasome pathway (UPP) plays important roles in host immunity against pathogens including viruses by inducing degradation of viral proteins. Previously a series of methods for retargeting substrates for ubiquitin-proteasome degradation have been successfully established. In this study, we attempted to design and construct artificial chimeric ubiquitin ligases (E3s) based on known human E3s in order to manually target HIV-1 integrase for ubiquitin proteasome pathway-mediated degradation. Herein, a series of prototypical chimeric E3s have been designed and constructed, and original substrate-binding domains of these E3s were replaced with host protein domains which interacted with viral proteins. After functional assessment screening, 146LI was identified as a functional chimeric E3 for HIV-1 NL4-3 integrase. 146LI was then further optimized to generate 146LIS (146LI short) which has been shown to induce Lys48-specific polyubiquitination and reduce protein level of HIV-1 NL4-3 integrase more effectively in cells. Lymphocyte cells with 146LIS knock-in generated by CRISPR/Cas-mediated homology-directed repair (HDR) showed remarkably decreased integration of HIV-1 NL4-3 viral DNAs and reduced viral replication without obvious cell cytotoxicity. Our study successfully obtained an artificial chimeric E3 which can induce Lys48-specific polyubiquitination and proteasome-mediated degradation of HIV-1 NL4-3 integrase, thus effectively inhibiting viral DNA integration and viral replication upon virus infection.
Seroprevalence of Neutralizing Antibodies against Six Human Adenovirus Types Indicates the Low Level of Herd Immunity in Young Children from Guangzhou, China
Xingui Tian, Ye Fan, Changbing Wang, Zhenwei Liu, Wenkuan Liu, Yun Xu, Chuncong Mo, Aiping You, Xiao Li, Xia Rong, Rong Zhou
doi: 10.1007/s12250-020-00307-1
Received: 29 June 2020 Accepted: 31 August 2020 Published: 09 November 2020
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Human adenoviruses (HAdVs) commonly cause many diseases such as respiratory diseases, gastroenteritis, cystitis worldwide. HAdV-3, -7, -4 and emergent HAdV-55 and HAdV-14 are the most important types causing severe respiratory diseases. There is no effective drug available for clinical treatment, and no vaccine available for the general population. Therefore, it is important to investigate the seroprevalence against HAdV for developing novel vaccines and vectors. In this study, we investigated the seroprevalence and titer levels of neutralizing antibodies (NAb) against HAdV-3, -4, -7, -14, -55, and -11 in total 278 healthy populations between 0 months and 49 years of age (228 children and 50 adults) from Guangzhou. In children under the age of 18 years, the seropositive rates were significantly increased against HAdV-3 at 12.07%, 33.96%, and 64.29% and against HAdV-7 at 0%, 18.87%, and 19.05% in age groups of 1–2, 3–5, and 6–17 years, respectively. The seroprevalence was very low (0%~8.1%) for all other four types. In adults aged between 18 and 49 years, HAdV-3, -4, and -7 (>50.00%) were the most common types, followed by HAdV-14 (38.00%), -55 (34.00%), and -11 (24.00%). Adults tended to have high NAb titers against HAdV-4 and -55. HAdV-55-seropositive donors tended to be HAdV-11- and HAdV-14-seropositive. These results indicated the low level of herd immunity against all six HAdV types in young children, and HAdV-14, -55, -11 in adults from Guangzhou City. Our findings demonstrate the importance of monitoring HAdV types and developing vaccines against HAdV for children and adults.
Repurposing of Antazoline Hydrochloride as an Inhibitor of Hepatitis B Virus DNA Secretion
Jing Li, Yangyang Hu, Yifei Yuan, Yinan Zhao, Qiqi Han, Canyu Liu, Xue Hu, Yuan Zhou, Yun Wang, Yu Guo, Chunchen Wu, Xinwen Chen, Rongjuan Pei
doi: 10.1007/s12250-020-00306-2
Received: 26 March 2020 Accepted: 16 September 2020 Published: 09 November 2020
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Hepatitis B virus (HBV) belongs to Hepadnaviridae family and mainly infects hepatocytes, which can cause acute or chronic hepatitis. Currently, two types of antiviral drugs are approved for chronic infection clinically: interferons and nucleos(t)ide analogues. However, the clinical cure for chronic infection is still rare, and it is a huge challenge for all researchers to develop high-efficiency, safe, non-tolerant, and low-toxicity anti-HBV drugs. Antazoline hydrochloride is a first-generation antihistamine with anticholinergic properties, and it is commonly used to relieve nasal congestion and in eye drops. Recently, an in vitro high-throughput evaluation system was constructed to screen nearly 800 compounds from the Food and Drug Administration (FDA)-approved Drug Library. We found that arbidol hydrochloride and antazoline hydrochloride can effectively reduce HBV DNA in the extracellular supernatant in a dose-dependent manner, with EC50 of 4.321 μmol/L and 2.910 μmol/L in HepAD38 cells, respectively. Moreover, the antiviral effects and potential mechanism of action of antazoline hydrochloride were studied in different HBV replication systems. The results indicate that antazoline hydrochloride also has a significant inhibitory effect on HBV DNA in the extracellular supernatant of Huh7 cells, with an EC50 of 2.349 μmol/L. These findings provide new ideas for screening and research related to HBV agents.
Loop-Mediated Isothermal Amplification Combined with Lateral Flow Dipstick for On-Site Diagnosis of African Swine Fever Virus
Lei Zuo, Zengxu Song, Yi Zhang, Xiwen Zhai, Yaru Zhai, Xueran Mei, Xin Yang, Hongning Wang
doi: 10.1007/s12250-020-00309-z
Received: 31 July 2020 Accepted: 18 September 2020 Published: 06 November 2020
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African Swine Fever Virus MGF360-12L Inhibits Type I Interferon Production by Blocking the Interaction of Importin α and NF-кB Signaling Pathway
Yisha Zhuo, Zeheng Guo, Tongtong Ba, Cheng Zhang, Lihua He, Cuiping Zeng, Hanchuan Dai
doi: 10.1007/s12250-020-00304-4
Received: 26 February 2020 Accepted: 13 July 2020 Published: 03 November 2020
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African swine fever (ASF) is an infectious transboundary disease of domestic pigs and wild boar and spreading throughout Eurasia. There is no vaccine and treatment available. Complex immune escape strategies of African swine fever virus (ASFV) are crucial factors affecting immune prevention and vaccine development. MGF360 genes have been implicated in the modulation of the IFN-I response. The molecular mechanisms contributing to innate immunity are poorly understood. In this study, we demonstrated that ASFV MGF360-12L (MGF360 families 12L protein) significantly inhibited the mRNA transcription and promoter activity of IFN-β and NF-кB, accompanied by decreases of IRF3, STING, TBK1, ISG54, ISG56 and AP-1 mRNA transcription. Also, MGF360-12L might suppress the nuclear localization of p50 and p65 mediated by classical nuclear localization signal (NLS). Additionally, MGF360-12L could interact with KPNA2, KPNA3, and KPNA4, which interrupted the interaction between p65 and KPNA2, KPNA3, KPNA4. We further found that MGF360-12L could interfere with the NF-кB nuclear translocation by competitively inhibiting the interaction between NF-кB and nuclear transport proteins. These findings suggested that MGF360-12L could inhibit the IFN-I production by blocking the interaction of importin a and NF-кB signaling pathway, which might reveal a novel strategy for ASFV to escape the host innate immune response.
Hantavirus Infection during Pregnancy
Deng-Hui Lu, Hong Jiang, Jian-Qi Lian
doi: 10.1007/s12250-020-00300-8
Received: 25 January 2020 Accepted: 07 August 2020 Published: 19 October 2020
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Hantavirus infection is a global health challenge, causing widespread public concern. In recent years, cases of hantavirus infection in pregnant women have been reported in many countries. The infected pregnant women and their fetuses appear to have more severe clinical symptoms and worse clinical outcomes. Hence, to study the prevalence of hantavirus infection in pregnant women, this study will focus on the epidemiological distribution of the virus, different virus species penetrating the placental barrier, and factors affecting the incidence and clinical outcome of the infection in pregnant women and their fetuses. In addition, this review will also discuss the diagnostic tools and treatments for pregnant patients and provide an overview of the relevant future research.
PTEN Lipid Phosphatase Activity Enhances Dengue Virus Production through Akt/FoxO1/Maf1 Signaling
Bin Liu, Ting-Ting Gao, Xiao-Yu Fu, Zhen-Hao Xu, Hao Ren, Ping Zhao, Zhong-Tian Qi, Zhao-Ling Qin
doi: 10.1007/s12250-020-00291-6
Received: 10 January 2020 Accepted: 31 July 2020 Published: 12 October 2020
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Dengue virus (DENV) is an arthropod-borne viral pathogen and a global health burden. Knowledge of the DENV-host interactions that mediate virus pathogenicity remains limited. Host lipid metabolism is hijacked by DENV for virus replication in which lipid droplets (LDs) play a key role during the virus lifecycle. In this study, we reveal a novel role for phosphatase and tensin homolog deleted on chromosome 10 (PTEN) in LDs-mediated DENV infection. We demonstrate that PTEN expression is downregulated upon DENV infection through post-transcriptional regulation and, in turn, PTEN overexpression enhances DENV replication. PTEN lipid phosphatase activity was found to decrease cellular LDs area and number through Akt/FoxO1/Maf1 signaling, which, together with autophagy, enhanced DENV replication and virus production. We therefore provide mechanistic insight into the interaction between lipid metabolism and the DENV replication cycle.
Inhibitory Activity of Honeysuckle Extracts against Influenza A Virus In Vitro and In Vivo
Mengwei Li, Yuxu Wang, Jing Jin, Jie Dou, Qinglong Guo, Xue Ke, Changlin Zhou, Min Guo
doi: 10.1007/s12250-020-00302-6
Received: 19 July 2019 Accepted: 11 September 2020 Published: 12 October 2020
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Honeysuckle has been used in the treatment of influenza virus infection for thousands of years in China. However, its main active components and the functional mechanisms remain to be elucidated. Here, four honeysuckle extracts, including acids extract, flavonoids extract, total extract and acids-flavonoids mixture, were prepared to clarify the main active antiviral components. The cytopathic effect reduction assay showed that all the four extracts inhibited the replication of influenza viruses H1N1, H3N2 and the oseltamivir-resistant mutant strain H1N1-H275Y. The acids-flavonoids mixture had the strongest inhibitory effects in vitro with EC50 values of 3.8, 4.1, and >20 μg/mL against H1N1, H3N2 and H1N1-H275Y, respectively, showing competitive antiviral activity with oseltamivir and ribavirin. Honeysuckle acids extract also showed the most significant antiviral activity in vivo. Oral administration of the acids extract at a dosage of 600 mg/kg/d effectively alleviated viral pneumonia, maintained body weight and improved the survival rate to 30% of the mice infected with a lethal dose of H1N1. The results of time-of-drug addition experiment and neuraminidase (NA) inhibition assay showed that honeysuckle extracts had a broad-spectrum inhibitory effect against influenza virus NAs. The flavonoid extract showed the strongest inhibitory effect on the NA of influenza virus H7N9 with an IC50 of 24.7 μg/mL. These results suggested that these extracts might exert their antiviral activity by suppressing the release of influenza viruses. Briefly, our findings demonstrate that acids and flavonoids extracts of honeysuckle are the major antiviral active components, and the acids extract has the potential to be developed into an antiviral agent against influenza virus, especially for oseltamivir-resistant viruses.
Application of Human Adenovirus Genotyping by Phylogenetic Analysis in an Outbreak to Identify Nosocomial Infection
Chuanyu Yang, Chunmei Zhu, Yuan Qian, Jie Deng, Baoyuan Zhang, Runan Zhu, Fang Wang, Yu Sun, Dongmei Chen, Qi Guo, Yutong Zhou, Lei Yu, Ling Cao, Linqing Zhao
doi: 10.1007/s12250-020-00299-y
Received: 14 May 2020 Accepted: 05 August 2020 Published: 01 October 2020
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Nosocomial infections are common in pediatric patients and can be fatal in infants and immunocompromised patients. In September 2018, a high positive rate of human adenovirus HAdV was occurred among hospitalized children in the Children's Hospital Affiliated to the Capital Institute of Paediatrics in Beijing. To investigate whether this outbreak of HAdV was related to nosocomial infections or the result of community infections, we collected respiratory specimens from patients with acute respiratory infections in a respiratory ward during June to December 2018, and screened for respiratory viruses. Among 1, 840 cases included, 95 (5.2%, 95/1840) were positive for HAdV and 81 were genotyped based on phylogenetic analysis, including seven as HAdV-1 (8.6%), 30 HAdV-3 (37.0%), two HAdV-6 (2.5%), and 42 HAdV-7 (51.9%). More HAdV-positive samples were collected in August (4.7%, 12/255), September (15.0%, 41/274) and October (6.9%, 17/247), with a peak in September 2018. By combining the results of HAdV phylogenetic analysis with clinical data of patients, there were 77 cases (4.2%, 77/1840; 81.1%, 77/95) excluded from nosocomial infections, eight cases representing possible infections transmitted by visitors or attending parents, three cases without sequences that might have been due to infection transmitted by roommates positive for HAdV, one case of a roommate without an HAdV sequence, and six cases that shared highly homologous sequences with those of their roommates, for which nosocomial infections might be considered. In conclusion, genotyping of HAdVs based on phylogenetic analysis combined with clinical information provides a powerful method to distinguish nosocomial infections from community acquired infection, especially when tracing the origins of nosocomial infections.
From Monovalent to Multivalent Vaccines, the Exploration for Potential Preventive Strategies Against Hand, Foot, and Mouth Disease (HFMD)
Xiangchuan He, Miaomiao Zhang, Chen Zhao, Peiyong Zheng, Xiaoyan Zhang, Jianqing Xu
doi: 10.1007/s12250-020-00294-3
Received: 22 April 2020 Accepted: 25 August 2020 Published: 30 September 2020
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Hand, foot, and mouth disease (HFMD) recently emerged as a global public threat. The licensure of inactivated enterovirus A71 (EV-A71) vaccine was the first step in using a vaccine to control HFMD. New challenges arise from changes in the pathogen spectrum while vaccines directed against other common serotypes are in the preclinical stage. The mission of a broad-spectrum prevention strategy clearly favors multivalent vaccines. The development of multivalent vaccines was attempted via the simple combination of potent monovalent vaccines or the construction of chimeric vaccines comprised of epitopes derived from different virus serotypes. The present review summarizes recent advances in HFMD vaccine development and discusses the next steps toward a safe and effective HFMD vaccine that is capable of establishing a cross-protective antibody response.
A Highly Attenuated Mumps Virus Strain of Genotype F Generated by Passaging in Vero Cells
Yajing Zhang, Lixia Xie, Benjie Chai, Juncheng Ruan, Yulin Gu, Biao Niu, Yachun Zhang, Zhenfang Fu, Qi An, Dayong Tian
doi: 10.1007/s12250-020-00292-5
Received: 24 February 2020 Published: 29 September 2020
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A Sensitive and High-Throughput Flow Cytometry-Based Assay for Measuring Antibody Neutralization of Human Adenovirus Type 3
Zhenwei Liu, Xingui Tian, Wenkuan Liu, Yuting Xian, Weilue Chen, Rong Zhou
doi: 10.1007/s12250-020-00295-2
Received: 18 January 2020 Accepted: 24 August 2020 Published: 29 September 2020
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The assessment of neutralization activity is an important step in the evaluation of neutralizing antibodies (NAbs). The traditional methods for measuring the antibody neutralization of human adenovirus type 3 (HAdV-3) are the microneu-tralization (MN) assay, which has insufficient sensitivity, and the plaque reduction neutralization test (PRNT), which is not suitable for high-throughput screening. Herein, we describe the development of a flow cytometry-based neutralization (FCN) assay for measuring the neutralization of sera, cell culture supernatants, and chimeric antibodies against HAdV-3 on the basis of a recombinant HAdV-3 (rHAdV-3) construct expressing the enhanced green fluorescent protein (EGFP). For flow cytometry-based assays, the optimal cell confluence was determined as 90%, and the virus was titrated using the assay. The established FCN assay follows the percentage law and an optimal MOI of not less than 5×10-4 was determined by using a purified chimeric antibody. In addition, comparison of the anti-HAdV-3 NAb titers of 72 human serum samples by the MN and FCN assays, showed that both assays correlated strongly with each other. Our FCN assay was an improvement over the MN assay because the observation period was reduced from 3 to 1 days and data analysis could be performed objectively and robotically. Importantly, the newly established FCN assay allows measurement of the neutralization activity of chimeric antibodies expressed in cell culture supernatants. Thus, this sensitive and high-throughput FCN assay is a useful alternative to the MN assay for measuring the antibody neutralization of HAdV-3 and for screening anti-HAdV-3 NAbs in cell culture supernatants.
Early Serum HBsAg Kinetics as Predictor of HBsAg Loss in Patients with HBeAg-Negative Chronic Hepatitis B after Treatment with Pegylated Interferonα-2a
Minghui Li, Lu Zhang, Yao Lu, Qiqi Chen, Huihui Lu, Fangfang Sun, Zhan Zeng, Gang Wan, Linqing Zhao, Yao Xie
doi: 10.1007/s12250-020-00290-7
Received: 19 January 2020 Accepted: 16 July 2020 Published: 25 September 2020
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Hepatitis B surface antigen (HBsAg) loss is an ideal treatment endpoint for patients with chronic hepatitis B (CHB). We investigated the predictive value of on-treatment HBsAg levels for HBsAg loss in hepatitis B e antigen (HBeAg)-negative CHB patients who received 120-week PEG-IFNα-2a treatment. Serum HBV DNA, HBsAg, and anti-HBs levels were assayed at baseline and every 3 months during the treatment. Of 81 patients, 12 achieved HBsAg loss, 20 achieved HBsAg < 100 IU/mL, and 49 maintained HBsAg≥100 IU/mL. HBsAg loss rate was only 3.7% at 48 weeks, while it reached to 11.1% and 14.8% after treatment of 96 weeks and 120 weeks. The cutoff HBsAg levels at 12 weeks predicting HBsAg loss at 96 weeks and 120 weeks of treatment were 400 IU/mL and 750 IU/mL, with AUC 0.725 and 0.722, positive predictive value (PPV) 29.41% and 30.56%, and negative predictive value (NPV) 93.75% and 97.78%, respectively. The cutoff HBsAg levels at 24 weeks predicting HBsAg loss at 96 weeks and 120 weeks of treatment were 174 IU/mL and 236 IU/mL respectively, with AUC 0.925 and 0.922, PPV 40.0% and 46.15%, and both NPV 100%. The predictive ability of the cutoff HBsAg levels at 24 weeks was better than that at 12 weeks for HBsAg loss at either 96 or 120 weeks (χ2=3.880, P=0.049 and χ2=4.412, P=0.036). These results indicate that extended therapy is critical to HBsAg loss in HBeAg-negative CHB patients during PEG-IFN treatment, and the HBsAg level at 24 weeks can be used to predict HBsAg loss during tailoring PEG-IFN therapy.
Novel SFTSV Phylogeny Reveals New Reassortment Events and Migration Routes
Xiaoli Wu, Mingyue Li, Yanfang Zhang, Boyun Liang, Junming Shi, Yaohui Fang, Zhengyuan Su, Mengmeng Li, Wenjing Zhang, Ling Xu, Jun Wang, Qiaoli Wu, Shuang Tang, Hualin Wang, Tao Zhang, Cheng Peng, Xin Zheng, Fei Deng, Shu Shen
doi: 10.1007/s12250-020-00289-0
Received: 08 May 2020 Accepted: 13 July 2020 Published: 22 September 2020
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Severe fever with thrombocytopenia syndrome virus (SFTSV), the causative agent of a febrile human disease, was first identified from central and eastern provinces in China, and later in Japan and South Korea. Hubei Province is one of the major SFTS epidemic areas in the central part of China. This study reported the isolation of 11 new SFTSV strains from patients in Hubei Province collected in 2017. Extensive phylogenetic analyses were conducted based on the complete coding sequences of SFTSV segments including the new strains. It was suggested that five different SFTSV genotypes were circulating in Hubei, and 15 reassortment patterns and migration pathways correlated with each genotype were identified, which was more than previously recognized. Hubei Province was more involved in the evolutionary events of SFTSV than that previously thought in which the evolutionary events of SFTSV were reported to be independent from those in other epidemic regions. Further divergence of SFTSV strains was suggested by pairwise comparison of SFTSV sequences from each genotype and sequence identity normalized to representative strain in genotype C1. Subsequently, amino acid variations specific for genotype(s), strain(s), or cluster(s) were inspected, which may be related to differential biological activity of SFTSV strains/genotypes. In conclusion, we analyzed the current status of SFTSV phylogeny in Hubei Province and discussed the possible events correlated to SFTSV evolution. It provided an in-depth insight into SFTSV evolution, raising concerns for the use of proper SFTSV strains in future studies.
Genetic and Molecular Characterization of H9N2 Avian Influenza Viruses Isolated from Live Poultry Markets in Hubei Province, Central China, 2013–2017
Zhibin Hu, Fuhu Peng, Zhenghui Xiong, Wanpo Zhang, Tingting Li, Yuejun Shi, Jun Xie, Xin Jin, Jingjing Huang, Hongde Xiao, Dingren Bi, Nianhua Song, Zili Li
doi: 10.1007/s12250-020-00260-z
Received: 17 January 2020 Accepted: 24 April 2020 Published: 14 September 2020
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H9N2 subtype avian influenza virus (AIV) is an influenza A virus that is widely spread throughout Asia, where it jeopardizes the poultry industry and provides genetic material for emerging human pathogens. To better understand the epidemicity and genetics of H9 subtype AIVs, we conducted active surveillance in live poultry markets (LPMs) in Hubei Province from 2013 to 2017. A total of 4798 samples were collected from apparent healthy poultry and environment. Real-time RT-PCR revealed that the positivity rate of influenza A was 26.6% (1275/4798), of which the H9 subtype accounted for 50.3% (641/1275) of the positive samples. Of the 132 H9N2 viral strains isolated, 48 representative strains were subjected to evolutionary analysis and genotyping. Phylogenetic analysis revealed that all H9N2 viral genes had 91.1%–100% nucleotide homology, clustered with genotype 57, and had high homology with human H9N2 viruses isolated from 2013 to 2017 in China. Using a nucleotide divergence cutoff of 95%, we identified ten distinct H9N2 genotypes that continued to change over time. Molecular analysis demonstrated that six H9N2 isolates had additional potential glycosylation sites at position 218 in the hemagglutinin protein, and all isolates had I155T and Q226L mutations. Moreover, 44 strains had A558V mutations in the PB2 protein and four had E627V mutations, along with H9N2 human infection strains A/Beijing/1/2016 and A/Beijing/1/2017. These results emphasize that the H9N2 influenza virus in Hubei continues to mutate and undergo mammalian adaptation changes, indicating the necessity of strengthening the surveillance of the AIV H9N2 subtype in LPMs.
Molecular Characterization of Human Respiratory Adenoviruses Infection in Xining City, China In 2018
Juan Yu, Shengcang Zhao, Huaxiang Rao
doi: 10.1007/s12250-020-00282-7
Received: 18 March 2020 Accepted: 05 August 2020 Published: 14 September 2020
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Porcine Immunoglobulin Fc Fused P30/P54 Protein of African Swine Fever Virus Displaying on Surface of S. cerevisiae Elicit Strong Antibody Production in Swine
Chen Chen, Deping Hua, Jingxuan Shi, Zheng Tan, Min Zhu, Kun Tan, Lilin Zhang, Jinhai Huang
doi: 10.1007/s12250-020-00278-3
Received: 06 December 2019 Accepted: 13 July 2020 Published: 11 September 2020
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African swine fever virus (ASFV) infects domestic pigs and European wild boars with strong, hemorrhagic and high mortality. The primary cellular targets of ASFV is the porcine macrophages. Up to now, no commercial vaccine or effective treatment available to control the disease. In this study, three recombinant Saccharomyces cerevisiae (S. cerevisiae) strains expressing fused ASFV proteins-porcine Ig heavy chains were constructed and the immunogenicity of the S. cerevisiae-vectored cocktail ASFV feeding vaccine was further evaluated. To be specific, the P30-Fcγ and P54-Fcα fusion proteins displaying on surface of S. cerevisiae cells were produced by fusing the Fc fragment of porcine immunoglobulin IgG1 or IgA1 with p30 or p54 gene of ASFV respectively. The recombinant P30-Fcγ and P54-Fcα fusion proteins expressed by S. cerevisiae were verified by Western blotting, flow cytometry and immunofluorescence assay. Porcine immunoglobulin Fc fragment fused P30/P54 proteins elicited P30/P54-specific antibody production and induced higher mucosal immunity in swine. The absorption and phagocytosis of recombinant S. cerevisiae strains in IPEC-J2 cells or porcine alveolar macrophage (PAM) cells were significantly enhanced, too. Here, we introduce a kind of cheap and safe oral S. cerevisiae-vectored vaccine, which could activate the specific mucosal immunity for controlling ASFV infection.
Seroprevalence of Dengue Virus among Young Adults in Beijing, China, 2019
Ran Wang, Dongying Fan, Lei Wang, Yueqi Li, Hongning Zhou, Na Gao, Jing An
doi: 10.1007/s12250-020-00285-4
Received: 16 May 2020 Accepted: 05 August 2020 Published: 11 September 2020
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Characterizing the Lassa Virus Envelope Glycoprotein Membrane Proximal External Region for Its Role in Fusogenicity
Junyuan Cao, Guangshun Zhang, Minmin Zhou, Yang Liu, Gengfu Xiao, Wei Wang
doi: 10.1007/s12250-020-00286-3
Received: 30 April 2020 Accepted: 22 July 2020 Published: 08 September 2020
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The membrane-proximal external region (MPER) of Lassa virus (LASV) glycoprotein complex (GPC) is critical in modulating its functionality. Till now, the high-resolution structure of the intact GPC, including MPER is not available. In this study, we used alanine substitution to scan all 16 residues located in LASV MPER. Western blotting and quantification fusion assay showed that the residues located at the C terminus of the HR2 (M414 and L415) and N terminus of the MPER (K417 and Y419) are critical for GPC-mediated membrane fusion function. Furthermore, cell surface biotinylation experiments revealed that M414A, K417A and Y419A expressed similar levels as WT, whereas L415A mutant led to a reduction of mature GPC on the cell surface. Moreover, substitution of these residues with the similar residue such as M414L, L415I, K417R and Y419F would partly compensate the loss of the fusion activity caused by the alanine mutant in these sites. Results from this study showed that several key residues in the MPER region are indispensable to promote the conformational changes that drive fusion events and shed light on the structure analysis of LASV GPC and anti-LASV therapeutics.
Termination of Transcription of LAT Increases the Amounts of ICP0 mRNA but Does Not Alter the Course of HSV-1 Infection in Latently Infected Murine Ganglia
Haifang Jiang, Jiaming Wu, Xianjie Liu, Ruitao Lu, Manling Zhou, Meiling Chen, Yonghong Liu, Grace Guoying Zhou, Wenmin Fu
doi: 10.1007/s12250-020-00287-2
Received: 20 May 2020 Accepted: 31 July 2020 Published: 07 September 2020
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On entering sensory ganglia, herpes simplex viruses 1 (HSV-1) establishes a latent infection with the synthesis of a latency associated transcript (LAT) or initiates productive infection with expression of a set of immediate early viral proteins. The precise mechanisms how expression of α genes is suppressed during the latency are unknown. One mechanism that has been proposed is illustrated in the case of ICP0, a key immediate early viral regulatory protein. Specifically, the 2 kb LAT intron is complementary to the 3′ terminal portion of ICP0 mRNA. To test the hypothesis that accumulation of LAT negatively affects the accumulation of ICP0 mRNA, we inserted a DNA fragment encoding two poly(A) sequences into LAT to early terminate LAT transcript without interrupting the complementary sequence of ICP0 transcript (named as SR 1603). Comparisons of the parent (SR 1601) and mutant (SR 1603) HSV-1 viruses showed the following: Neurons harboring latent SR1603 virus accumulated equivalent amounts of viral DNA but higher amounts of ICP0 mRNA and lower amounts of LAT, when compared to neurons harboring the SR1601 virus. One notable difference between the two viruses is that viral RNA accumulation in explanted ganglia harboring SR1603 virus initiated significantly sooner than that in neurons harboring SR1601 virus, suggesting that ICP0 may act as an activator of viral gene expression in permissive cells. Collectively, these data suggest that increased ICP0 mRNA by suppressed LAT did not affect the establishment of latency in latently infected murine ganglia.
Flu Universal Vaccines: New Tricks on an Old Virus
Ruikun Du, Qinghua Cui, Lijun Rong
doi: 10.1007/s12250-020-00283-6
Received: 06 June 2020 Accepted: 05 August 2020 Published: 01 September 2020
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Conventional influenza vaccines are based on predicting the circulating viruses year by year, conferring limited effectiveness since the antigenicity of vaccine strains does not always match the circulating viruses. This necessitates development of universal influenza vaccines that provide broader and lasting protection against pan-influenza viruses. The discovery of the highly conserved immunogens (epitopes) of influenza viruses provides attractive targets for universal vaccine design. Here we review the current understanding with broadly protective immunogens (epitopes) and discuss several important considerations to achieve the goal of universal influenza vaccines.
Identification of Aristolactam Derivatives That Act as Inhibitors of Human Immunodeficiency Virus Type 1 Infection and Replication by Targeting Tat-Mediated Viral Transcription
YoungHyun Shin, Chul Min Park, Hong Gi Kim, Dong-Eun Kim, Min Suk Choi, Jeong-ah Kim, Byeong-Sun Choi, Cheol-Hee Yoon
doi: 10.1007/s12250-020-00274-7
Received: 15 May 2020 Published: 10 August 2020
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Despite the success of antiretroviral therapy (ART), efforts to develop new classes of antiviral agents have been hampered by the emergence of drug resistance. Dibenzo-indole-bearing aristolactams are compounds that have been isolated from various plants species and which show several clinically relevant effects, including anti-inflammatory, antiplatelet, and anti-mycobacterial actions. However, the effect of these compounds on human immunodeficiency virus type 1 (HIV-1) infection has not yet been studied. In this study, we discovered an aristolactam derivative bearing dibenzo[cd, f]indol-4(5H)-one that had a potent anti-HIV-1 effect. A structure-activity relationship (SAR) study using nine synthetic derivatives of aristolactam identified the differing effects of residue substitutions on the inhibition of HIV-1 infection and cell viability. Among the compounds tested,1,2,8,9-tetramethoxy-5-(2-(piperidin-1-yl)ethyl)-dibenzo[cd, f]indol-4(5H)-one (Compound 2) exhibited the most potent activity by inhibiting HIV-1 infection with a half-maximal inhibitory concentration (IC50) of 1.03 μmol/L and a half-maximal cytotoxic concentration (CC50) of 16.91 μmol/L (selectivity index,16.45). The inhibitory effect of the compounds on HIV-1 infection was linked to inhibition of the viral replication cycle. Mode-of-action studies showed that the aristolactam derivatives did not affect reverse transcription or integration; instead, they specifically inhibited Tat-mediated viral transcription. Taken together, these findings show that several aristolactam derivatives impaired HIV-1 infection by inhibiting the activity of Tat-mediated viral transcription, and suggest that these derivatives could be antiviral drug candidates.
A Novel Vibriophage vB_VcaS_HC Containing Lysogeny-Related Gene Has Strong Lytic Ability against Pathogenic Bacteria
Chengcheng Li, Zengmeng Wang, Jiulong Zhao, Long Wang, Guosi Xie, Jie Huang, Yongyu Zhang
doi: 10.1007/s12250-020-00271-w
Received: 02 March 2020 Accepted: 08 June 2021 Published: 07 August 2020
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To avoid the negative effects of antibiotics, using phage to prevent animal disease becomes a promising method in aquaculture. Here, a lytic phage provisionally named vB_VcaS_HC that can infect the pathogen (i.e., Vibrio campbellii 18) of prawn was isolated. The phage has an isometric head and a non-contractile tail. During phage infection, the induced host mortality in 5.5 h reached ca. 96%, with a latent period of 1.5 h and a burst size of 172 PFU/cell. It has an 81, 566 bp circular dsDNA genome containing 121 open reading frames (ORFs), and ca. 71% of the ORFs are functionally unknown. Comparative genomic and phylogenetic analysis revealed that it is a novel phage belonging to Delepquintavirus, Siphoviridae, Caudovirales. In the phage genome, besides the ordinary genes related to structure assembly and DNA metabolism, there are 10 auxiliary metabolic genes. For the first time, the pyruvate phosphate dikinase (PPDK) gene was found in phages whose product is a key rate-limiting enzyme involving Embden-Meyerhof-Parnas (EMP) reaction. Interestingly, although the phage has a strong bactericidal activity and contains a potential lysogeny related gene, i.e., the recombinase (RecA) gene, we did not find the phage turned into a lysogenic state. Meanwhile, the phage genome does not contain any bacterial virulence gene or antimicrobial resistance gene. This study represents the first comprehensive characterization of a lytic V. campbellii phage and indicates that it is a promising candidate for the treatment of V. campbellii infections.
SRP54 Negatively Regulates IFN-Beta Production and Antiviral Response by Targeting RIG-I and MDA5
Dong-Peng Wang, Hong-Yan Zhang, Bo-Wei Liao, Zhen Tong, Zhi-Sheng Xu, Yan-Yi Wang, Yan Yang
doi: 10.1007/s12250-020-00267-6
Received: 11 April 2020 Accepted: 08 June 2020 Published: 07 August 2020
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During virus infection, RIG-I-like receptors (RLRs) recognize viral RNAs and recruit the adaptor protein VISA to activate downstream signaling, leading to activation of transcription factors NF-κB and IRF3, which collaborate to induce type I interferons (IFNs). IFNs further induce expression of hundreds of IFN-stimulated genes (ISGs) that suppress viral replication and facilitate the adaptive immune response. Dysregulated production of IFNs is implicated in various immune diseases. Here we identified Signal Recognition Particle 54 (SRP54) as a negative regulator of RLRs-induced antiviral signaling. Overexpression of SRP54 inhibited RNA virus-triggered induction of IFN-β and increased viral replication, whereas knockdown of SRP54 had opposite effects. Mechanistically, SRP54 interacted with both RIG-I and MDA5 and impaired their association with VISA. Our findings demonstrate that SRP54 acts as a negative regulator of RLRs-mediated innate immune response by disrupting the recruitment of VISA to RIG-I/MDA5.
Immune Responses to Varicella-Zoster Virus Glycoprotein E Formulated with Poly(Lactic-co-Glycolic Acid) Nanoparticles and Nucleic Acid Adjuvants in Mice
Yunfei Wang, Jialong Qi, Han Cao, Cunbao Liu
doi: 10.1007/s12250-020-00261-y
Received: 17 April 2020 Accepted: 01 June 2020 Published: 05 August 2020
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The subunit herpes zoster vaccine Shingrix is superior to attenuated vaccine Zostavax in both safety and efficacy, yet its unlyophilizable liposome delivery system and the limited supply of naturally sourced immunological adjuvant QS-21 still need to be improved. Based on poly(lactic-co-glycolic acid) (PLGA) delivery systems that are stable during the lyophilization and rehydration process and using a double-emulsion (w/o/w) solvent evaporation method, we designed a series of nanoparticles with varicella-zoster virus antigen glycoprotein E (VZV-gE) as an antigen and nucleic acids including polyinosinic-polycytidylic acid (Poly I:C) and phosphodiester CpG oligodeoxynucleotide (CpG ODN), encapsulated as immune stimulators. While cationic lipids (DOTAP) have more potential than neutral lipids (DOPC) for activating gE-specific cell-mediated immunity (CMI) in immunized mice, especially when gE is encapsulated in and presented on the surface of nanoparticles, PLGA particles without lipids have the greatest potential to induce not only the highest gE-specific IgG titers but also the strongest gE-specific CMI responses, including the highest proportions of interferon-γ (IFN-γ)- and interleukin-2 (IL-2)-producing CD4+/CD8+T cells according to a flow cytometry assay and the greatest numbers of IFN-γ- and IL-2-producing splenocytes according to an enzyme-linked immunospot (ELISPOT) assay. These results showed that immune-stimulating nucleic acids together with the PLGA delivery system showed promise as a safe and economical varicella and zoster vaccine candidate.
Human Cytomegalovirus Influences Host circRNA Transcriptions during Productive Infection
Jingui Deng, Yujing Huang, Qing Wang, Jianming Li, Yanping Ma, Ying Qi, Zhongyang Liu, Yibo Li, Qiang Ruan
doi: 10.1007/s12250-020-00275-6
Received: 26 April 2020 Accepted: 08 July 2020 Published: 05 August 2020
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Human cytomegalovirus (HCMV) is a double-strand DNA virus widely infected in human. Circular RNAs (circRNAs) are non-coding RNAs with most functions of which keep unknown, and the effects of HCMV productive infection on host circRNA transcriptions remain unclear. In this study, we profiled 283 host circRNAs that significantly altered by HCMV productive infection in human embryonic lung fibroblasts (HELF) by RNA deep sequencing and bioinformatics analysis. Among these, circSP100, circMAP3K1, circPLEKHM1, and circTRIO were validated for their transcriptions and sequences. Furthermore, characteristics of circSP100 were investigated by RT-qPCR and northern blot. It was implied that circSP100 was produced from the sense strand of the SP100 gene containing six exons. Kinetics of circSP100 and SP100 mRNA were significantly different after infection: circSP100 levels increased gradually along with infection, whereas SP100 mRNA levels increased in the beginning and dropped at 24 h post-infection (hpi). Meanwhile, a total number of 257 proteins, including 10 HCMV encoding proteins, were identified potentially binding to cytoplasmic circSP100 by RNA antisense purification (RAP) and mass spectrometry. Enrichment analysis showed these proteins were mainly involved in the spliceosome, protein processing, ribosome, and phagosome pathways, suggesting multiple functions of circSP100 during HCMV infection.
Prediction of the Receptorome for the Human-Infecting Virome
Zheng Zhang, Sifan Ye, Aiping Wu, Taijiao Jiang, Yousong Peng
doi: 10.1007/s12250-020-00259-6
Received: 13 April 2020 Accepted: 01 June 2020 Published: 28 July 2020
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The virus receptors are key for the viral infection of host cells. Identification of the virus receptors is still challenging at present. Our previous study has shown that human virus receptor proteins have some unique features including high N-glycosylation level, high number of interaction partners and high expression level. Here, a random-forest model was built to identify human virus receptorome from human cell membrane proteins with an accepted accuracy based on the combination of the unique features of human virus receptors and protein sequences. A total of 1424 human cell membrane proteins were predicted to constitute the receptorome of the human-infecting virome. In addition, the combination of the random-forest model with protein-protein interactions between human and viruses predicted in previous studies enabled further prediction of the receptors for 693 human-infecting viruses, such as the enterovirus, norovirus and West Nile virus. Finally, the candidate alternative receptors of the SARS-CoV-2 were also predicted in this study. As far as we know, this study is the first attempt to predict the receptorome for the human-infecting virome and would greatly facilitate the identification of the receptors for viruses.
Genetic Variation of Multiple Serotypes of Enteroviruses Associated with Hand, Foot and Mouth Disease in Southern China
Yonghong Zhou, Le Van Tan, Kaiwei Luo, Qiaohong Liao, Lili Wang, Qi Qiu, Gang Zou, Ping Liu, Nguyen To Anh, Nguyen Thi Thu Hong, Min He, Xiaoman Wei, Shuanbao Yu, Tommy Tsan-Yuk Lam, Jie Cui, H. Rogier van Doorn, Hongjie Yu
doi: 10.1007/s12250-020-00266-7
Received: 12 November 2019 Accepted: 06 July 2020 Published: 28 July 2020
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Enteroviruses (EVs) species A are a major public health issue in the Asia–Pacific region and cause frequent epidemics of hand, foot and mouth disease (HFMD) in China. Mild infections are common in children; however, HFMD can also cause severe illness that affects the central nervous system. To molecularly characterize EVs, a prospective HFMD virological surveillance program was performed in China between 2013 and 2016. Throat swabs, rectal swabs and stool samples were collected from suspected HFMD patients at participating hospitals. EVs were detected using generic real-time and nested reverse transcription-polymerase chain reactions (RT-PCRs). Then, the complete VP1 regions of enterovirus A71 (EV-A71), coxsackievirus A16 (CVA16) and CVA6 were sequenced to analyze amino acid changes and construct a viral molecular phylogeny. Of the 2836 enrolled HFMD patients, 2, 517 (89%) were EV positive. The most frequently detected EVs were CVA16 (32.5%, 819), CVA6 (31.2%, 785), and EV-A71 (20.4%, 514). The subgenogroups CVA16_B1b, CVA6_D3a and EV-A71_C4a were predominant in China and recombination was not observed in the VP1 region. Sequence analysis revealed amino acid variations at the 30, 29 and 44 positions in the VP1 region of EV-A71, CVA16 and CVA6 (compared to the respective prototype strains BrCr, G10 and Gdula), respectively. Furthermore, in 21 of 24 (87.5%) identified EV-A71 samples, a known amino acid substitution (D31N) that may enhance neurovirulence was detected. Our study provides insights about the genetic characteristics of common HFMD-associated EVs. However, the emergence and virulence of the described mutations require further investigation.
The Multifaceted Roles of TAM Receptors during Viral Infection
Zhao-Yang Wang, Pei-Gang Wang, Jing An
doi: 10.1007/s12250-020-00264-9
Received: 18 April 2020 Accepted: 08 June 2020 Published: 27 July 2020
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Tyro3, Axl, and Mertk (TAM) receptors play multiple roles in a myriad of physiological and pathological processes, varying from promoting the phagocytic clearance of apoptotic cells, sustaining the immune and inflammatory homeostasis, maintaining the blood-brain barrier (BBB) integrity and central nervous system (CNS) homeostasis, to mediating cancer malignancy and chemoresistance. Growth arrest-specific protein 6 (Gas6) and protein S (Pros1) are the two ligands that activate TAM receptors. Recently, TAM receptors have been reported to mediate cell entry and infection of multitudinous enveloped viruses in a manner called apoptotic mimicry. Moreover, TAM receptors are revitalized during viral entry and infection, which sequesters innate immune and inflammatory responses, facilitating viral replication and immune evasion. However, accumulating evidence have now proposed that TAM receptors are not required for the infection of these viruses in vivo. In addition, TAM receptors protect mice against the CNS infection of neuroinvasive viruses and relieve the brain lesions during encephalitis. These protective effects are achieved through maintaining BBB integrity, attenuating pro-inflammatory cytokine production, and promoting neural cell survival. TAM receptors also regulate the programmed cell death modes of virus-infected cells, which have profound impacts on the pathogenesis and outcome of infection. Here, we systematically review the functionalities and underlying mechanisms of TAM receptors and propose the potential application of TAM agonists to prevent severe viral encephalitis.
TAR DNA-Binding Protein 43 is Cleaved by the Protease 3C of Enterovirus A71
Xiaoman Wo, Yuan Yuan, Yong Xu, Yang Chen, Yao Wang, Shuoxuan Zhao, Lexun Lin, Xiaoyan Zhong, Yan Wang, Zhaohua Zhong, Wenran Zhao
doi: 10.1007/s12250-020-00262-x
Received: 21 March 2020 Accepted: 01 June 2020 Published: 21 July 2020
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Enterovirus A71 (EV-A71) is one of the etiological pathogens leading to hand, foot, and mouth disease (HFMD), which can cause severe neurological complications. The neuropathogenesis of EV-A71 infection is not well understood. The mislocalization and aggregation of TAR DNA-binding protein 43 (TDP-43) is the pathological hallmark of amyotrophic lateral sclerosis (ALS). However, whether TDP-43 was impacted by EV-A71 infection is unknown. This study demonstrated that TDP-43 was cleaved during EV-A71 infection. The cleavage of TDP-43 requires EV-A71 replication rather than the activated caspases due to viral infection. TDP-43 is cleaved by viral protease 3C between the residues 331Q and 332S, while mutated TDP-43 (Q331A) was not cleaved. In addition, mutated 3C which lacks the protease activity failed to induce TDP-43 cleavage. We also found that TDP-43 was translocated from the nucleus to the cytoplasm, and the mislocalization of TDP-43 was induced by viral protease 2A rather than 3C. Taken together, we demonstrated that TDP-43 was cleaved by viral protease and translocated to the cytoplasm during EV-A71 infection, implicating the possible involvement of TDP-43 in the pathogenesis of EV-A71infection.
Freeze-Drying Formulations Increased the Adenovirus and Poxvirus Vaccine Storage Times and Antigen Stabilities
Ye Chen, Qibin Liao, Tianyue Chen, Yuchao Zhang, Weien Yuan, Jianqing Xu, Xiaoyan Zhang
doi: 10.1007/s12250-020-00250-1
Received: 19 April 2020 Published: 21 July 2020
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Successful vaccines induce specific immune responses and protect against various viral and bacterial infections. Noninactivated vaccines, especially viral vector vaccines such as adenovirus and poxvirus vaccines, dominate the vaccine market because their viral particles are able to replicate and proliferate in vivo and produce lasting immunity in a manner similar to natural infection. One challenge of human and livestock vaccination is vaccine stability related to the antigenicity and infectivity. Freeze-drying is the typical method to maintain virus vaccine stability, while cold chain transportation is required for temperatures about 2 ℃–8 ℃. The financial and technological resource requirements hinder vaccine distribution in underdeveloped areas. In this study, we developed a freeze-drying formula consisting of bovine serum albumin (BSA), L-glutamic acid (L-Glu), polyethylene glycol (PEG), and dextran (DEX) to improve the thermal stability and activity of viral vaccines, including vaccinia recombinant vaccine (rTTV-OVA) and adenovirus vaccine (Ad5-ENV). We compared a panel of five different formulations (PEG: DEX: BSA: L-GLU=50:9:0:0(#1), 50:5:4:0(#2), 50:10:9:0(#3), 50:0:0:9(#4), and 50:1:0:8(#5), respectively) and optimized the freeze-drying formula for rTTV-OVA and Ad5-ENV. We found that the freeze-drying formulations #2 and #3 could maintain rTTV-OVA infectivity at temperatures of 4 ℃ and 25 ℃ and that rTTV-OVA immunogenicity was retained during lyophilization. However, formulations #4 and #5 maintained Ad5-ENV infectivity under the same conditions, and Ad5-ENV immunogenicity had maximum retention with freeze-drying formulation #4. In summary, we developed new freeze-drying formulations that increased virus vaccine storage times and retained immunogenicity at an ambient temperature.
Identification, Isolation, and Characterization of an Ectromelia Virus New Strain from an Experimental Mouse
Jun Wang, Xiaoping Liu, Qiong Zhu, Qiaoli Wu, Shuang Tang, Lei Zhang, Zhaojun Fan, Zhihong Hu, Hualin Wang, Fei Deng, Shu Shen
doi: 10.1007/s12250-020-00263-w
Received: 17 January 2020 Accepted: 15 June 2020 Published: 21 July 2020
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Identification and Molecular Characterization of a New Omono River Virus Isolated from Culex Tritaeniorhynchus in Yunnan, China
Yawei Zhang, Xin Qiang, Xiaofang Guo, Honghong Peng, Si Qin, Yujun Cui, Hang Fan, Hongning Zhou, Jiusong Zhang, Jinglin Wang, Yigang Tong
doi: 10.1007/s12250-020-00247-w
Received: 17 January 2020 Accepted: 28 April 2020 Published: 20 July 2020
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Perinatal Vertical Transmission of Chikungunya Virus in Ruili, a Town on the Border between China and Burma
Jia-Yuan Shen, Man Li, Lyu Xie, Jia-Rong Mao, Hong-Ning Zhou, Pei-Gang Wang, Jin-Yong Jiang, Jing An
doi: 10.1007/s12250-020-00245-y
Received: 20 January 2020 Accepted: 18 May 2020 Published: 16 July 2020
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The Prevalence, Genetic Characterization, and Evolutionary Analysis of Porcine Pegivirus in Guangdong, China
Yongsheng Xie, Xiaoru Wang, Junsen Feng, Liuming Wei, Gen Li, Guangbin Si, Yibo Chen, He Yan, Dongsheng He
doi: 10.1007/s12250-020-00240-3
Received: 07 December 2019 Accepted: 15 April 2020 Published: 08 July 2020
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Porcine pegivirus (PPgV) is a member of the Pegivirus genus in the Flaviviridae family. PPgV is an emerging virus that has been discovered in swine herds in Germany, the United States, China, Poland, Italy, and the United Kingdom, indicating a wide geographical distribution. In this retrospective study, 339 pig serum samples were collected from 20 different commercial swine farms located in nine cities in Guangdong Province, China, from 2016 to 2018, to investigate the prevalence and genetic diversity of PPgV in this geographical region. PPgV was detected in 55% (11/20) of the farms using nested reverse transcription PCR, with 6.2% (21/339) of pigs testing positive for PPgV. The yearly PPgV-positive rate increased from 2.6% to 7.5% between 2016 and 2018. Sequencing of PPgV-positive samples identified two complete polyprotein genes and seven partial NS5B genes from different farms. Comparative analysis of the polyprotein genes revealed that PPgV sequences obtained in this study showed 87.4%–97.2% similarity at the nucleotide level and 96.5%–99.4% similarity at the amino acid level with the reference sequences. Sequence alignment and phylogenetic analysis of the complete polyprotein gene and partial NS5B and NS3 genes demonstrated a high genetic similarity with the samples from the USA. The finding of the wide distribution of PPgV in swine herds in Guangdong Province will contribute to the understanding of the epidemiological characteristics and genetic evolution of PPgV in China.
Epidemiology and Genotypic Diversity of Eurasian Avian-Like H1N1 Swine Influenza Viruses in China
Zhaomin Feng, Wenfei Zhu, Lei Yang, Jia Liu, Lijuan Zhou, Dayan Wang, Yuelong Shu
doi: 10.1007/s12250-020-00257-8
Received: 24 April 2020 Accepted: 10 June 2020 Published: 07 July 2020
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Eurasian avian-like H1N1 (EA H1N1) swine influenza virus (SIV) outside European countries was first detected in Hong Kong Special Administrative Region (Hong Kong, SAR) of China in 2001. Afterwards, EA H1N1 SIVs have become predominant in pig population in this country. However, the epidemiology and genotypic diversity of EA H1N1 SIVs in China are still unknown. Here, we collected the EA H1N1 SIVs sequences from China between 2001 and 2018 and analyzed the epidemic and phylogenic features, and key molecular markers of these EA H1N1 SIVs. Our results showed that EA H1N1 SIVs distributed in nineteen provinces/municipalities of China. After a long-time evolution and transmission, EA H1N1 SIVs were continuously reassorted with other co-circulated influenza viruses, including 2009 pandemic H1N1 (A(H1N1)pdm09), and triple reassortment H1N2 (TR H1N2) influenza viruses, generated 11 genotypes. Genotype 3 and 5, both of which were the reassortments among EA H1N1, A(H1N1)pdm09 and TR H1N2 viruses with different origins of M genes, have become predominant in pig population. Furthermore, key molecular signatures were identified in EA H1N1 SIVs. Our study has drawn a genotypic diversity image of EA H1N1 viruses, and could help to evaluate the potential risk of EA H1N1 for pandemic preparedness and response.
Controversial: Early Innate Responses to Hepatitis B Virus Infection, an Explanation for Viral Persistence?
Ruth Broering, Xufeng Luo, Jia Liu, Mengji Lu
doi: 10.1007/s12250-020-00235-0
Received: 11 February 2020 Accepted: 03 April 2020 Published: 06 July 2020
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Recovery and Genetic Characterization of a West Nile Virus Isolate from China
Yan Guo, Hongjiang Wang, Songtao Xu, Hangyu Zhou, Chao Zhou, Shihong Fu, Mengli Cheng, Fan Li, Yongqiang Deng, Xiaofeng Li, Huanyu Wang, Cheng-Feng Qin
doi: 10.1007/s12250-020-00246-x
Received: 09 May 2020 Accepted: 25 May 2020 Published: 06 July 2020
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West Nile virus (WNV) is an important neurotropic flavivirus that is widely distributed globally. WNV strain XJ11129 was first isolated in Xinjiang, China, and its genetic and biological characteristics remain largely unknown. In this study, phylogenetic and sequence analyses revealed that XJ11129 belongs to lineage 1a and shares high genetic identity with the highly pathogenic strain NY99. Then, the full-length genomic cDNA of XJ11129 was amplified and assembled using a modified Gibson assembly (GA) method. The virus (named rXJ11129) was successfully rescued in days following this method. Compared with other wild-type WNV isolates, rXJ11129 exhibited virulence indistinguishable from that of the NY99 strain in vivo. In summary, the genomic and virulence phenotypes of rXJ11129 were characterized in vivo and in vitro, and these data will improve the understanding of the spread and pathogenesis of this reemerging virus.
GTPase Activity of MxB Contributes to Its Nuclear Location, Interaction with Nucleoporins and Anti-HIV-1 Activity
Linlin Xie, Zhao Ju, Chaojie Zhong, Yingjun Wu, Yuxing Zan, Wei Hou, Yong Feng
doi: 10.1007/s12250-020-00249-8
Received: 08 March 2020 Accepted: 27 April 2020 Published: 06 July 2020
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The human myxovirus resistance 2 (Mx2/MxB) protein, a member of interferon (IFN)-inducible dynamin-like large GTPases, restricts a number of virus infections. Inhibition of these viruses occurs at poorly-defined steps after viral entry and has a common requirement for MxB oligomerization. However, the GTPase activity is essential for the anti-viral effects of MxB against herpesviruses and HBV but not HIV-1. To understand the role of MxB GTPase activity, including GTP binding and GTP hydrolysis, in restriction of HIV-1 infection, we genetically separated these two functions and evaluated their contributions to restriction. We found that both the GTP binding and hydrolysis function of MxB involved in the restriction of HIV-1 replication. The GTPase activity of MxB contributed to its nuclear location, interaction with nucleoporins (NUPs) and HIV-1 capsids. Furthermore, MxB disrupted the association between NUPs and HIV-1 cores dependently upon its GTPase activity. The function of GTPase activity was therefore multi-faceted, led to fundamentally distinct mechanisms employed by wild-type MxB and GTPase activity defective MxB mutations to restrict HIV-1 replication.
Differential CircRNA Expression Profiles in PK-15 Cells Infected with Pseudorabies Virus Type Ⅱ
Haimin Li, Wen Tang, Yulan Jin, Weiren Dong, Yan Yan, Jiyong Zhou
doi: 10.1007/s12250-020-00255-w
Received: 08 November 2019 Accepted: 26 May 2020 Published: 02 July 2020
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Circular RNAs (circRNAs) belong to a class of non-coding RNAs with diverse biological functions. However, little is known about their roles in case of pseudorabies virus (PrV) infection. Here, we analyzed the expression profile of host circRNAs from a virulent PrV type Ⅱ strain DX (PrV-DX) infected and an attenuated gE/TK deficient (gE-TK-PrV) strain of PrV infected PK-15 cells. CircRNAs were identified by find_circ and analyzed with DESeq 2. Compared with the mock cells, 449 differentially expressed (DE) circRNAs (233 down-regulated and 216 up-regulated) from PrV-DX infected and 578 DE circRNAs (331 down-regulated and 247 up-regulated) from gE-TK-PrV infected PK-15 cells were identified. In addition, 459 DE circRNAs (164 down-regulated and 295 up-regulated) between the PrV-DX and gE-TK-PrV infected cells were identified. The expression patterns of 13 circRNAs were validated by reverse transcription quantitative real-time PCR (RT-qPCR) and results were similar as of RNA-seq. The putative target miRNA binding sites of DE circRNAs were predicted by using miRanda and psRobot. The circRNA-miRNA-mRNA network was constructed and certain miRNAs that have possible roles in antiviral immune response, such as miR-210 and miR-340, were predicted. GO and KEGG pathway analysis demonstrated that DE circRNAs were enriched in the processes such as cellular metabolism, protein binding, RNA degradation and regulation of actin cytoskeleton. Collectively, these findings might provide the useful information for a better understanding of mechanisms underlying the interaction between PrV-Ⅱ and host cells.
Novel HCV-Like Virus Detected in Avian Livers in Southern China and Its Implications for Natural Recombination Events
Gang Lu, Jiawei Zhao, Jiajun Ou, Shoujun Li
doi: 10.1007/s12250-020-00256-9
Received: 12 March 2020 Accepted: 26 April 2020 Published: 02 July 2020
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Emergence of Zika Virus in Culex tritaeniorhynchus and Anopheles sinensis Mosquitoes in China
Jing Wang, Hongbin Xu, Song Song, Rui Cheng, Na Fan, Shihong Fu, Shaozai Zhang, Xu Ziqian, Ying He, Wenwen Lei, Fan Li, Huanyu Wang, Xiaoqing Lu, Guodong Liang
doi: 10.1007/s12250-020-00239-w
Received: 11 October 2019 Accepted: 08 April 2020 Published: 02 July 2020
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Zika virus (ZIKV) has been isolated from mosquitoes such as Aedes, Mansonia uniformis, and Culex perfuscus; However, the isolation of ZIKV from Anopheles sinensis and Culex tritaeniorhynchus has not yet been reported. In June and July 2018, 22, 985 mosquitoes and 57, 500 midges were collected in Jiangxi Province in southeastern China. Among them, six strains of ZIKV were isolated from mosquitoes: four from An. sinensis and two from Cx. tritaeniorhynchus. Molecular genetic analysis showed that the ZIKV isolated from An. sinensis and Cx. tritaeniorhynchus belonged to genotype 2 in the Asian evolutionary branch of ZIKV. In addition, the ZIKV strains isolated from An. sinensis and Cx. tritaeniorhynchus had amino acid substitutions identical to ZIKV strains prevalent in South America since 2015. This study is the first to isolate ZIKV from mosquito specimens collected in the wild of Jiangxi Province, China; This is also the first time that ZIKV has been isolated from An. sinensis and Cx. tritaeniorhynchus. Given that An. sinensis and Cx. tritaeniorhynchus have a very wide geographical distribution in China and even in eastern and southern Asia, the isolation of several strains of ZIKV from these two mosquitoes poses new challenges for the prevention and control of ZIKV infection in the mainland of China and countries and regions with the same distribution of mosquitoes.
Fur Seal Feces-Associated Circular DNA Virus Identified in Pigs in Anhui, China
Zhibin Shi, Chunguo Liu, Huanliang Yang, Yan Chen, Hua Liu, Lili Wei, Zaisi Liu, Yongping Jiang, Xijun He, Jingfei Wang
doi: 10.1007/s12250-020-00232-3
Received: 11 October 2019 Accepted: 07 March 2020 Published: 02 June 2020
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Fur seal feces-associated circular DNA virus (FSfaCV) is an unclassified circular replication-associated protein (Rep)-encoding single-stranded (CRESS) DNA virus that has been detected in mammals (fur seals and pigs). The biology and epidemiology of the virus remain largely unknown. To investigate the virus diversity among pigs in Anhui Province, China, we pooled 600 nasal samples in 2017 and detected viruses using viral metagenomic methods. From the assembled contigs, 12 showed notably high nucleotide acid sequence similarities to the genome sequences of FSfaCVs. Based on these sequences, a full-length genome sequence of the virus was then obtained using overlapping PCR and sequencing, and the virus was designated as FSfaCV-CHN (GenBank No. MK462122). This virus shared 91.3% and 90.9% genome-wide nucleotide sequence similarities with the New Zealand fur seal strain FSfaCV-as50 and the Japanese pig strain FSfaCV-JPN1, respectively. It also clustered with the two previously identified FSfaCVs in a unique branch in the phylogenetic tree based on the open reading frame 2 (ORF2), Rep-coding gene, and the genome of the reference CRESS DNA viruses. Further epidemiological investigation using samples collected in 2018 showed that the overall positive rate for the virus was 56.4% (111/197) in Anhui Province. This is the first report of FSfaCVs identified in pigs in China, and further epidemiological studies are warranted to evaluate the influence of the virus on pigs.
Concerns on Vaccine against Varicella Caused by Varicella-Zoster Virus Infection
Wen-Bo Zeng, Fukun Zhang, Shuang Cheng, Jin-yan Sun, Hongjie Shen, Min-Hua Luo
doi: 10.1007/s12250-020-00231-4
Received: 08 January 2020 Accepted: 17 April 2020 Published: 28 May 2020
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On the Calculation of TCID50 for Quantitation of Virus Infectivity
Chengfeng Lei, Jian Yang, Jia Hu, Xiulian Sun
doi: 10.1007/s12250-020-00230-5
Received: 10 March 2020 Accepted: 15 April 2020 Published: 26 May 2020
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Construction and Characterization of a Novel Recombinant Attenuated and Replication-Deficient Candidate Human Adenovirus Type 3 Vaccine: "Adenovirus Vaccine Within an Adenovirus Vector"
Yuqian Yan, Shuping Jing, Liqiang Feng, Jing Zhang, Zhiwei Zeng, Min Li, Shan Zhao, Junxian Ou, Wendong Lan, Wenyi Guan, Xiaowei Wu, Jianguo Wu, Donald Seto, Qiwei Zhang
doi: 10.1007/s12250-020-00234-1
Received: 22 February 2020 Accepted: 13 April 2020 Published: 26 May 2020
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Human adenoviruses (HAdVs) are highly contagious and result in large number of acute respiratory disease (ARD) cases with severe morbidity and mortality. Human adenovirus type 3 (HAdV-3) is the most common type that causes ARD outbreaks in Asia, Europe, and the Americas. However, there is currently no vaccine approved for its general use. The hexon protein contains the main neutralizing epitopes, provoking strong and lasting immunogenicity. In this study, a novel recombinant and attenuated adenovirus vaccine candidate against HAdV-3 was constructed based on a commercially-available replication-defective HAdV-5 gene therapy and vaccine vector. The entire HAdV-3 hexon gene was integrated into the E1 region of the vector by homologous recombination using a bacterial system. The resultant recombinants expressing the HAdV-3 hexon protein were rescued in AD293 cells, identified and characterized by RT-PCR, Western blots, indirect immunofluorescence, and electron microscopy. This potential vaccine candidate had a similar replicative efficacy as the wild-type HAdV-3 strain. However, and importantly, the vaccine strain had been rendered replication-defective and was incapable of replication in A549 cells after more than twenty-generation passages in AD293 cells. This represents a significant safety feature. The mice immunized both intranasally and intramuscularly by this vaccine candidate raised significant neutralizing antibodies against HAdV-3. Therefore, this recombinant, attenuated, and safe adenovirus vaccine is a promising HAdV-3 vaccine candidate. The strategy of using a clinically approved and replication-defective HAdV-5 vector provides a novel approach to develop universal adenovirus vaccine candidates against all the other types of adenoviruses causing ARDs and perhaps other adenovirus-associated diseases.
Potential m6A and m5C Methylations within the Genome of A Chinese African Swine Fever Virus Strain
Lijia Jia, Jianjun Chen, Haizhou Liu, Wenhui Fan, Depeng Wang, Jing Li, Di Liu
doi: 10.1007/s12250-020-00217-2
Received: 05 January 2020 Accepted: 07 March 2020 Published: 08 April 2020
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Monitoring Neutralization Property Change of Evolving Hantaan and Seoul Viruses with a Novel Pseudovirus-Based Assay
Tingting Ning, Ling Wang, Shuo Liu, Jian Ma, Jianhui Nie, Weijin Huang, Xuguang Li, Yuhua Li, Youchun Wang
doi: 10.1007/s12250-020-00237-y
Received: 20 December 2019 Accepted: 03 April 2020 Published: 12 June 2019
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The Hantaan virus (HTNV) and Seoul virus (SEOV) mutants have accumulated over time. It is important to determine whether their neutralizing epitopes have evolved, thereby making the current vaccine powerless. However, it is impossible to determine by using traditional plaque reduction neutralization test (PRNT), because it requires large numbers of live mutant strains. Pseudovirus-based neutralization assays (PBNA) were developed by employing vesicular stomatitis virus (VSV) backbone incorporated with HTNV or SEOV glycoproteins (VSVΔG*-HTNVG or VSVΔG*-SEOVG). 56 and 51 single amino acid substitutions of glycoprotein (GP) in HTNV and SEOV were selected and introduced into the reference plasmid. Then the mutant pseudoviruses were generated and tested by PBNA. The PBNA results were highly correlated with PRNT ones with R2 being 0.91 for VSVΔG*-HTNVG and 0.82 for VSVΔG*-SEOVG. 53 HTNV mutant pseudoviruses and 46 SEOV mutants were successfully generated. Importantly, by using PBNA, we found that HTNV or SEOV immunized antisera could neutralize all the corresponding 53 HTNV mutants or the 46 SEOV mutants respectively. The novel PBNA enables us to closely monitor the effectiveness of vaccines against large numbers of evolving HTNV and SEOV. And the current vaccine remains to be effective for the naturally occurring mutants.
First Fatal Infection and Phylodynamic Analysis of Severe Fever with Thrombocytopenia Syndrome Virus in Jilin Province, Northeastern China
Xu Zhang, Nina Wang, Zedong Wang, Lihe Che, Chen Chen, Wen-Zhong Zhao, Quan Liu
doi: 10.1007/s12250-020-00228-z
Received: 30 October 2019 Accepted: 16 March 2020 Published: 26 May 2019
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Review
A Crowned Killer's Résumé: Genome, Structure, Receptors, and Origin of SARS-CoV-2
Shichuan Wang, Mirko Trilling, Kathrin Sutter, Ulf Dittmer, Mengji Lu, Xin Zheng, Dongliang Yang, Jia Liu
2020, 35(6): 673-684.  doi: 10.1007/s12250-020-00298-z
Received: 20 July 2020 Accepted: 31 August 2020 Published: 17 October 2020
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The recent emergence and rapid global spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pose an unprecedented medical and socioeconomic crisis, and the disease caused by it, Coronavirus disease 2019 (COVID-19), was declared a pandemic by the World Health Organization (WHO) on March 11, 2020. Chinese scientists and physicians rapidly identified the causative pathogen, which turned out to be a novel betacoronavirus with high sequence similarities to bat and pangolin coronaviruses. The scientific community has ignited tremendous efforts to unravel the biological underpinning of SARS-CoV-2, which constitutes the foundation for therapy and vaccine development strategies. Here, we summarize the current state of knowledge on the genome, structure, receptor, and origin of SARS-CoV-2.
COVID-19: Antiviral Agents, Antibody Development and Traditional Chinese Medicine
Wenyi Guan, Wendong Lan, Jing Zhang, Shan Zhao, Junxian Ou, Xiaowei Wu, Yuqian Yan, Jianguo Wu, Qiwei Zhang
2020, 35(6): 685-698.  doi: 10.1007/s12250-020-00297-0
Received: 03 July 2020 Accepted: 31 August 2020 Published: 30 September 2020
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The World Health Organization (WHO) has declared coronavirus disease 2019 (COVID-19) is the first pandemic caused by coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Currently, there is no effective anti-SARS-CoV-2 drug approved worldwide for treatment of patients with COVID-19. Therapeutic options in response to the COVID-19 outbreak are urgently needed. To facilitate the better and faster development of therapeutic COVID-19 drugs, we present an overview of the global promising therapeutic drugs, including repurposing existing antiviral agents, network-based pharmacology research, antibody development and traditional Chinese medicine. Among all these drugs, we focus on the most promising drugs (such as favipiravir, tocilizumab, SARS-CoV-2 convalescent plasma, hydroxychloroquine, Lianhua Qingwen, interferon beta-1a, remdesivir, etc.) that have or will enter the final stage of human testing—phase III–IV clinical trials.
Summary of the Detection Kits for SARS-CoV-2 Approved by the National Medical Products Administration of China and Their Application for Diagnosis of COVID-19
Ruhan A, Huijuan Wang, Wenling Wang, Wenjie Tan
2020, 35(6): 699-712.  doi: 10.1007/s12250-020-00331-1
Received: 23 July 2020 Accepted: 25 November 2020 Published: 22 December 2020
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The on-going global pandemic of coronavirus disease 2019 (COVID-19) caused by a novel coronavirus called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been underway for about 11 months. Through November 20,2020,51 detection kits for SARS-CoV-2 nucleic acids (24 kits), antibodies (25 kits), or antigens (2 kits) have been approved by the National Medical Products Administration of China (NMPA). Convenient and reliable SARS-CoV-2 detection assays are urgently needed worldwide for strategic control of the pandemic. In this review, the detection kits approved in China are summarised and the three types of tests, namely nucleic acid, serological and antigen detection, which are available for the detection of COVID-19 are discussed in detail. The development of novel detection kits will lay the foundation for the control and prevention of the COVID-19 pandemic globally.
Human Monoclonal Antibodies: On the Menu of Targeted Therapeutics Against COVID-19
Junsen Chen, Rui Huang, Yiwen Nie, Xinyue Wen, Ying Wu
2020, 35(6): 713-724.  doi: 10.1007/s12250-020-00327-x
Received: 24 August 2020 Accepted: 11 November 2020 Published: 04 January 2021
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Coronavirus disease 2019 (COVID-19), reminiscent of the severe acute respiratory syndrome (SARS) outbreak in 2003, has been a tragic disaster to people all over the world. As there is no specific drug for COVID-19, neutralizing antibodies are attracting more and more attention as one of the most effective means to combat the pandemic. Here, we introduced the etiological and serological characteristics of COVID-19, discussed the current stage of development of human monoclonal antibodies against SARS-CoV-2 and summarized the antigenic epitopes in the S glycoprotein, which may deepen the understanding of the profile of immune recognition and response against SARS-CoV-2 and provide insight for the design of effective vaccines and antibody-based therapies.
Research Article
A Small-Scale Medication of Leflunomide as a Treatment of COVID-19 in an Open-Label Blank-Controlled Clinical Trial
Ke Hu, Mengmei Wang, Yang Zhao, Yunting Zhang, Tao Wang, Zhishui Zheng, Xiaochen Li, Shaolin Zeng, Dong Zhao, Honglin Li, Ke Xu, Ke Lan
2020, 35(6): 725-733.  doi: 10.1007/s12250-020-00258-7
Received: 03 June 2020 Accepted: 16 June 2020 Published: 21 July 2020
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We recently reported that inhibitors against human dihydroorotate dehydrogenase (DHODH) have broad-spectrum antiviral activities including their inhibitory efficacies on SARS-CoV-2 replication in infected cells. However, there are limited data from clinical studies to prove the application of DHODH inhibitors in Coronavirus disease 2019 (COVID-19) patients. In the present study, we evaluated Leflunomide, an approved DHODH inhibitor widely used as a modest immune regulator to treat autoimmune diseases, in treating COVID-19 disease with a small-scale of patients. Cases of 10 laboratory-confirmed COVID-19 patients of moderate type with obvious opacity in the lung were included. Five of the patients were treated with Leflunomide, and another five were treated as blank controls without a placebo. All the patients accepted standard supportive treatment for COVID-19. The patients given Leflunomide had a shorter viral shedding time (median of 5 days) than the controls (median of 11 days, P=0.046). The patients given Leflunomide also showed a significant reduction in C-reactive protein levels, indicating that immunopathological inflammation was well controlled. No obvious adverse effects were observed in Leflunomide-treated patients, and they all discharged from the hospital faster than controls. This preliminary study on a small-scale compassionate use of Leflunomide provides clues for further understanding of Leflunomide as a potential antiviral drug against COVID-19.
Mild Cytokine Elevation, Moderate CD4+ T Cell Response and Abundant Antibody Production in Children with COVID-19
Ran Jia, Xiangshi Wang, Pengcheng Liu, Xiaozhen Liang, Yanling Ge, He Tian, Hailing Chang, Hao Zhou, Mei Zeng, Jin Xu
2020, 35(6): 734-743.  doi: 10.1007/s12250-020-00265-8
Received: 02 July 2020 Accepted: 06 July 2020 Published: 22 July 2020
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Children with Coronavirus Disease 2019 (COVID-19) were reported to show milder symptoms and better prognosis than their adult counterparts, but the difference of immune response against SARS-CoV-2 between children and adults hasn't been reported. Therefore we initiated this study to figure out the features of immune response in children with COVID-19. Sera and whole blood cells from 19 children with COVID-19 during different phases after disease onset were collected. The cytokine concentrations, SARS-CoV-2 S-RBD or N-specific antibodies and T cell immune responses were detected respectively. In children with COVID-19, only 3 of 12 cytokines were increased in acute sera, including interferon (IFN)-γ-induced protein 10 (IP10), interleukin (IL)-10 and IL-16. We observed an increase in T helper (Th)-2 cells and a suppression in regulatory T cells (Treg) in patients during acute phase, but no significant response was found in the IFN-γ-producing or tumor necrosis factor (TNF)-α-producing CD8+ T cells in patients. S-RBD and N IgM showed an early induction, while S-RBD and N IgG were prominently induced later in convalescent phase. Potent S-RBD IgA response was observed but N IgA seemed to be inconspicuous. Children with COVID-19 displayed an immunophenotype that is less inflammatory than adults, including unremarkable cytokine elevation, moderate CD4+ T cell response and inactive CD8+ T cell response, but their humoral immunity against SARS-CoV-2 were as strong as adults. Our finding presented immunological characteristics of children with COVID-19 and might give some clues as to why children develop less severe disease than adults.
Dynamic Changes of Antibodies to SARS-CoV-2 in COVID-19 Patients at Early Stage of Outbreak
Huaqing Shu, Shuzhen Wang, Shunan Ruan, Yaxin Wang, Jiancheng Zhang, Yin Yuan, Hong Liu, Yongran Wu, Ruiting Li, Shangwen Pan, Yaqi Ouyang, Shiying Yuan, Peng Zhou, You Shang
2020, 35(6): 744-751.  doi: 10.1007/s12250-020-00268-5
Received: 11 May 2020 Accepted: 15 June 2020 Published: 27 July 2020
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The coronavirus disease 2019 (COVID-19), caused by SARS-CoV-2, has spread around the world with high mortality. To diagnose promptly and accurately is the vital step to effectively control its pandemic. Dynamic characteristics of SARS-CoV-2-specific antibodies which are important for diagnosis of infection have not been fully demonstrated. In this retrospective, single-center, observational study, we enrolled the initial 131 confirmed cases of COVID-19 at Jin-Yin-Tan Hospital who had at least one-time antibody tested during their hospitalization. The dynamic changes of IgM and IgG antibodies to SARS-CoV-2 nucleocapsid protein in 226 serum samples were detected by ELISA. The sensitivities of IgM and IgG ELISA detection were analyzed. Result showed that the sensitivity of the IgG ELISA detection (92.5%) was significantly higher than that of the IgM (70.8%) (P < 0.001). The meantimes of seroconversion for IgM and IgG were 6 days and 3 days, respectively. The IgM and IgG antibody levels peaked at around 18 days and 23 days, and then IgM fell to below the baseline level at about day 36, whereas IgG maintained at a relatively high level. In conclusion, antibodies should be detected to aid in diagnosis of COVID-19 infection. IgG could be a sensitive indicator for retrospective diagnosis and contact tracing, while IgM could be an indicator of early infection.
Serologic Response to SARS-CoV-2 in COVID-19 Patients with Different Severity
Wen-Hua Kong, Rong Zhao, Jun-Bo Zhou, Fang Wang, De-Guang Kong, Jian-Bin Sun, Qiong-Fang Ruan, Man-Qing Liu
2020, 35(6): 752-757.  doi: 10.1007/s12250-020-00270-x
Received: 31 May 2020 Accepted: 07 July 2020 Published: 23 July 2020
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The immense patient number caused by coronavirus disease 2019 (COVID-19) global pandemic brings the urge for more knowledge about its immunological features, including the profile of basic immune parameters. In this study, eighty-eight reported COVID-19 patients in Wuhan were recruited from January to February, 2020, including 32 severe/critical cases and 56 mild/moderate cases. Their mean age was 56.43 years (range 17-83) and gender ratio (male/female) was 43:45. We tested SARS-CoV-2 RNA with commercial kits, investigated the level of serologic IgM and IgG antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) using magnetic particle chemiluminescence immunoassays, and compared the results of serologic tests and nucleic acid test (NAT). Among 88 patients, 95.45% were confirmed as positive by the combination of NAT and antibody test, which was significantly higher (P < 0.001) than by single nucleic acid test (73.86%) or serologic test (65.91%). Then the correlation between temporal profile and the level of antibody response was analyzed. It showed that seroconversion started on day 5 after disease onset and IgG level was rose earlier than IgM. Comparison between patients with different disease severity suggested early seroconversion and high antibody titer were linked with less severe clinical symptoms. These results supported the combination of serologic testing and NAT in routine COVID-19 diagnosis and provided evidence on the temporal profile of antibody response in patients with different disease severity.
Discrimination of False Negative Results in RT-PCR Detection of SARS-CoV-2 RNAs in Clinical Specimens by Using an Internal Reference
Yafei Zhang, Changtai Wang, Mingfeng Han, Jun Ye, Yong Gao, Zhongping Liu, Tengfei He, Tuantuan Li, Mengyuan Xu, Luping Zhou, Guizhou Zou, Mengji Lu, Zhenhua Zhang
2020, 35(6): 758-767.  doi: 10.1007/s12250-020-00273-8
Received: 25 May 2020 Accepted: 15 July 2020 Published: 04 August 2020
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Reverse transcription-polymerase chain reaction (RT-PCR) is an essential method for specific diagnosis of SARS-CoV-2 infection. Unfortunately, false negative test results are often reported. In this study, we attempted to determine the principal causes leading to false negative results of RT-PCR detection of SARS-CoV-2 RNAs in respiratory tract specimens. Multiple sputum and throat swab specimens from 161 confirmed COVID-19 patients were tested with a commercial fluorescent RT-PCR kit targeting the ORF1ab and N regions of SARS-CoV-2 genome. The RNA level of a cellular housekeeping gene ribonuclease P/MRP subunit p30 (RPP30) in these specimens was also assessed by RT-PCR. Data for a total of 1052 samples were retrospectively re-analyzed and a strong association between positive results in SARS-CoV-2 RNA tests and high level of RPP30 RNA in respiratory tract specimens was revealed. By using the ROC-AUC analysis, we identified Ct cutoff values for RPP30 RT-PCR which predicted false negative results for SARS-CoV-2 RT-PCR with high sensitivity (95.03%–95.26%) and specificity (83.72%–98.55%) for respective combination of specimen type and amplification reaction. Using these Ct cutoff values, false negative results could be reliably identified. Therefore, the presence of cellular materials, likely infected host cells, are essential for correct SARS-CoV-2 RNA detection by RT-PCR in patient specimens. RPP30 could serve as an indicator for cellular content, or a surrogate indicator for specimen quality. In addition, our results demonstrated that false negativity accounted for a vast majority of contradicting results in SARS-CoV-2 RNA test by RT-PCR.
Patients with Prolonged Positivity of SARS-CoV-2 RNA Benefit from Convalescent Plasma Therapy: A Retrospective Study
Yongran Wu, Ke Hong, Lianguo Ruan, Xiaobo Yang, Jiancheng Zhang, Jiqian Xu, Shangwen Pan, Lehao Ren, Lu Chen, Chaolin Huang, You Shang
2020, 35(6): 768-775.  doi: 10.1007/s12250-020-00281-8
Received: 09 July 2020 Accepted: 03 August 2020 Published: 31 August 2020
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Convalescent plasma therapy has been implemented in a few cases of severe coronavirus disease 2019. No report about convalescent plasma therapy in treating patients with prolonged positivity of SARS-CoV-2 RNA has been published. In this study, we conducted a retrospective observational study in 27 patients with prolonged positivity of SARS-CoV-2 RNA, the clinical benefit of convalescent plasma therapy were analyzed. qRT-PCR test of SARS-CoV-2 RNA turned negative (≤ 7 days) in a part of patients (early negative group, n = 15) after therapy, others (late negative group, n = 12) turned negative in more than 7 days. Pulmonary imaging improvement was confirmed in 7 patients in early negative group and 8 in late negative group after CP therapy. Viral load decreased in early negative group compared with late negative group at day 3, 5, 7 after implementing convalescent plasma therapy. Patients in early negative group had a shorter median length of hospital stay. In conclusion, convalescent plasma therapy might help eliminate virus and shorten length of hospital stay in patients with prolonged positivity of SARS-CoV-2 RNA.
Comparative Antiviral Efficacy of Viral Protease Inhibitors against the Novel SARS-CoV-2 In Vitro
Leike Zhang, Jia Liu, Ruiyuan Cao, Mingyue Xu, Yan Wu, Weijuan Shang, Xi Wang, Huanyu Zhang, Xiaming Jiang, Yuan Sun, Hengrui Hu, Yufeng Li, Gang Zou, Min Zhang, Lei Zhao, Wei Li, Xiaojia Guo, Xiaomei Zhuang, Xing-Lou Yang, Zheng-Li Shi, Fei Deng, Zhihong Hu, Gengfu Xiao, Manli Wang, Wu Zhong
2020, 35(6): 776-784.  doi: 10.1007/s12250-020-00288-1
Received: 04 August 2020 Accepted: 14 August 2020 Published: 10 September 2020
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The recent outbreak of novel coronavirus pneumonia (COVID-19) caused by a new coronavirus has posed a great threat to public health. Identifying safe and effective antivirals is of urgent demand to cure the huge number of patients. Virus-encoded proteases are considered potential drug targets. The human immunodeficiency virus protease inhibitors (lopinavir/ritonavir) has been recommended in the global Solidarity Trial in March launched by World Health Organization. However, there is currently no experimental evidence to support or against its clinical use. We evaluated the antiviral efficacy of lopinavir/ritonavir along with other two viral protease inhibitors in vitro, and discussed the possible inhibitory mechanism in silico. The in vitro to in vivo extrapolation was carried out to assess whether lopinavir/ritonavir could be effective in clinical. Among the four tested compounds, lopinavir showed the best inhibitory effect against the novel coronavirus infection. However, further in vitro to in vivo extrapolation of pharmacokinetics suggested that lopinavir/ritonavir could not reach effective concentration under standard dosing regimen [marketed as Kaletra®, contained lopinavir/ritonavir (200 mg/50 mg) tablets, recommended dosage is 400 mg/10 mg (2 tablets) twice daily]. This research concluded that lopinavir/ritonavir should be stopped for clinical use due to the huge gap between in vitro IC50 and free plasma concentration. Nevertheless, the structure–activity relationship analysis of the four inhibitors provided further information for de novel design of future viral protease inhibitors of SARS-CoV-2.
Identifying the Risk of SARS-CoV-2 Infection and Environmental Monitoring in Airborne Infectious Isolation Rooms (AIIRs)
Zhi-Gang Song, Yan-Mei Chen, Fan Wu, Lin Xu, Bang-Fang Wang, Lei Shi, Xiao Chen, Fa-Hui Dai, Jia-Lei She, Jian-Min Chen, Edward C. Holmes, Tong-Yu Zhu, Yong-Zhen Zhang
2020, 35(6): 785-792.  doi: 10.1007/s12250-020-00301-7
Received: 28 May 2020 Accepted: 31 August 2020 Published: 28 September 2020
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Healthcare workers (HCWs) are at high risk of occupational exposure to the new pandemic human coronavirus, SARS-CoV-2, and are a source of nosocomial transmission in airborne infectious isolation rooms (AIIRs). Here, we performed comprehensive environmental contamination surveillance to evaluate the risk of viral transmission in AIIRs with 115 rooms in three buildings at the Shanghai Public Health Clinical Center, Shanghai, during the treatment of 334 patients infected with SARS-CoV-2. The results showed that the risk of airborne transmission of SARS-CoV-2 in AIIRs was low (1.62%, 25/1544) due to the directional airflow and strong environmental hygiene procedures. However, we detected viral RNA on the surface of foot-operated openers and bathroom sinks in AIIRs (viral load: 55.00–3154.50 copies/mL). This might be a source of contamination to connecting corridors and object surfaces through the footwear and gloves used by HCWs. The risk of infection was eliminated by the use of disposable footwear covers and the application of more effective environmental and personal hygiene measures. With the help of effective infection control procedures, none of 290 HCWs was infected when working in the AIIRs at this hospital. This study has provided information pertinent for infection control in AIIRs during the treatment of COVID-19 patients.