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A SARS-like cluster of circulating bat coronaviruses shows potential for human emergence



The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome (MERS)-CoV underscores the threat of cross-species transmission events leading to outbreaks in humans. Here we examine the disease potential of a SARS-like virus, SHC014-CoV, which is currently circulating in Chinese horseshoe bat populations. Using the SARS-CoV reverse genetics system, we generated and characterized a chimeric virus expressing the spike of bat coronavirus SHC014 in a mouse-adapted SARS-CoV backbone. The results indicate that group 2b viruses encoding the SHC014 spike in a wild-type backbone can efficiently use multiple orthologs of the SARS receptor human angiotensin converting enzyme II (ACE2), replicate efficiently in primary human airway cells and achieve in vitro titers equivalent to epidemic strains of SARS-CoV. Additionally, in vivo experiments demonstrate replication of the chimeric virus in mouse lung with notable pathogenesis. Evaluation of available SARS-based immune-therapeutic and prophylactic modalities revealed poor efficacy; both monoclonal antibody and vaccine approaches failed to neutralize and protect from infection with CoVs using the novel spike protein. On the basis of these findings, we synthetically re-derived an infectious full-length SHC014 recombinant virus and demonstrate robust viral replication both in vitro and in vivo. Our work suggests a potential risk of SARS-CoV re-emergence from viruses currently circulating in bat populations.
Corrigendum: Multiphoton imaging reveals a new leukocyte recruitment
paradigm in the glomerulus
Sapna Devi, Anqi Li, Clare L V Westhorpe, Camden Y Lo, Latasha D Abeynaike, Sarah L Snelgrove, Pam Hall, Joshua D Ooi,
Christopher G Sobey, A Richard Kitching & Michael J Hickey
Nat. Med. 19, 107–112 (2013); published online 16 December 2012; corrected after print 12 August 2015
In the published article, in the Online Methods section, it is stated that the dose of DHE used is 20 mg/kg, when in fact DHE was administered at
2 mg/kg. The error has been corrected in the HTML and PDF versions of the article.
Corrigendum: PAR1 signaling regulates the retention and recruitment of
EPCR-expressing bone marrow hematopoietic stem cells
Shiri Gur-Cohen, Tomer Itkin, Sagarika Chakrabarty, Claudine Graf, Orit Kollet, Aya Ludin, Karin Golan, Alexander Kalinkovich,
Guy Ledergor, Eitan Wong, Elisabeth Niemeyer, Ziv Porat, Ayelet Erez, Irit Sagi, Charles T Esmon, Wolfram Ruf & Tsvee Lapidot
Nat. Med. 21, 1307–1317 (2015); published online 12 October 2015; corrected after print 18 November 2015
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of the article.
Corrigendum: Myeloid-derived growth factor (C19orf10) mediates cardiac
repair following myocardial infarction
Mortimer Korf-Klingebiel, Marc R Reboll, Stefanie Klede, Torben Brod, Andreas Pich, Felix Polten, L Christian Napp, Johann Bauersachs,
Arnold Ganser, Eva Brinkmann, Ines Reimann, Tibor Kempf, Hans W Niessen, Jacques Mizrahi, Hans-Joachim Schönfeld,
Antonio Iglesias, Maria Bobadilla, Yong Wang & Kai C Wollert
Nat. Med. 21, 140–149 (2015); published online 12 January 2015; corrected after print 19 November 2015
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error has been corrected in the HTML and PDF versions of the article.
Corrigendum: A SARS-like cluster of circulating bat coronaviruses shows
potential for human emergence
Vineet D Menachery, Boyd L Yount Jr, Kari Debbink, Sudhakar Agnihothram, Lisa E Gralinski, Jessica A Plante, Rachel L Graham,
Trevor Scobey, Xing-Yi Ge, Eric F Donaldson, Scott H Randell, Antonio Lanzavecchia, Wayne A Marasco, Zhengli-Li Shi & Ralph S Baric
Nat. Med.; doi:10.1038/nm.3985; corrected 20 November 2015
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EcoHealth Alliance, to Z.-L.S. The error has been corrected for the print, PDF and HTML versions of this article.
Corrigendum: Long-term glycemic control using polymer-encapsulated
human stem cell–derived beta cells in immune-competent mice
Arturo J Vegas, Omid Veiseh, Mads Gürtler, Jeffrey R Millman, Felicia W Pagliuca, Andrew R Bader, Joshua C Doloff, Jie Li,
Michael Chen, Karsten Olejnik, Hok Hei Tam, Siddharth Jhunjhunwala, Erin Langan, Stephanie Aresta-Dasilva, Srujan Gandham,
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npg © 2016 Nature America, Inc. All rights reserved.
... Typical symptoms of MERS include fever, cough, diarrhea, and shortness of breath. Some patients with MERS exhibit serious respiratory disease which may result in death [1][2][3][4][5][6][7][8][9][10][11][12][13]. Molecular investigation indicated that bats in Saudi Arabia are infected with several corona viruses and virus from one bat showed 100% nucleotide identity to virus from the human index case-patient indicating that bats might play a role in human infection [7]. ...
... SARS-related corona viruses are thought to be transmitted from bats to humans in origin. Furthermore, some bat SARS-related corona viruses have been previously shown to have the potential to infect humans [5][6][7][8][9][10]. SARS-CoV-2 is transmitted to human directly through respiratory droplets of infected people or indirectly through contact with virus-contaminated surfaces and substances [8]. ...
... The relationship between humans and bats is small. In 2015, a report was published in the Chinese media claiming the addition of the s-co-14 gene to sars-cov could infect humans in addition to mice, but no scientific source supported the report [8,[12][13][14], but Corona virus with the help of an RNA genome has a high potential for mutation and transmission to humans [15]. However, there is speculation that the sars-cov-2 virus is of laboratory origin and was released from a laboratory in Wuhan, China. ...
... A small region within the spike proteins of sarbecoviruses, known as the receptor binding domain (RBD), contains all of the structural information necessary to engage with the host receptor. We and others have experimentally classified the majority of published sarbecovirus RBDs into different clades based on sequence and functional data: clade 1, identified in Asian bats, contains no deletions and binds to host receptor, Angiotensin-Converting Enzyme 2 (ACE2), whereas clade 2, also identified in Asian bats, contains 2 deletions and does not use ACE2 and clade 3 viruses, found more widely in African and European bats, contain 1 deletion and have recently been shown can infect using primarily bat ACE2 [1][2][3][4][5][6][7][8][9][10]. In 2021, several viruses were identified in China that comprise a fourth clade that also interact with ACE2 [11]. ...
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Spillover of sarbecoviruses from animals to humans has resulted in outbreaks of severe acute respiratory syndrome SARS-CoVs and the ongoing COVID-19 pandemic. Efforts to identify the origins of SARS-CoV-1 and -2 has resulted in the discovery of numerous animal sarbecoviruses–the majority of which are only distantly related to known human pathogens and do not infect human cells. The receptor binding domain (RBD) on sarbecoviruses engages receptor molecules on the host cell and mediates cell invasion. Here, we tested the receptor tropism and serological cross reactivity for RBDs from two sarbecoviruses found in Russian horseshoe bats. While these two viruses are in a viral lineage distinct from SARS-CoV-1 and -2, the RBD from one virus, Khosta 2, was capable of using human ACE2 to facilitate cell entry. Viral pseudotypes with a recombinant, SARS-CoV-2 spike encoding for the Khosta 2 RBD were resistant to both SARS-CoV-2 monoclonal antibodies and serum from individuals vaccinated for SARS-CoV-2. Our findings further demonstrate that sarbecoviruses circulating in wildlife outside of Asia also pose a threat to global health and ongoing vaccine campaigns against SARS-CoV-2
... Subunit 1 is responsible for binding the virus to host cell receptors; therefore, it is a determining factor of pathogenicity and tropism in coronavirus. It is likely that the recombination identified in subunit 1 had an adaptive impact in BtMf-Yunnan2020, as has been suggested for other coronaviruses [121][122][123][124]. Finally, both BtMf-Yunnan2020 and MlYN20 presented an ORF7 unlike the other myotacoviruses; however, these proteins had a low reciprocal identity. ...
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Significant efforts have been made to characterize viral diversity in bats from China. Many of these studies were prospective and focused mainly on Rhinolophus bats that could be related to zoonotic events. However, other species of bats that are part of ecosystems identified as virus diversity hotspots have not been studied in-depth. We analyzed the virome of a group of Myotis fimbriatus bats collected from the Yunnan Province during 2020. The virome of M. fimbriatus revealed the presence of families of pathogenic viruses such as Coronavirus, Astrovirus, Mastadenovirus, and Picornavirus, among others. The viral sequences identified in M. fimbriatus were characterized by significant divergence from other known viral sequences of bat origin. Complex phylogenetic landscapes implying a tendency of co-specificity and relationships with viruses from other mammals characterize these groups. The most prevalent and abundant virus in M. fimbriatus individuals was an alphacoronavirus. The genome of this virus shows evidence of recombination and is likely the product of ancestral host-switch. The close phylogenetic and ecological relationship of some species of the Myotis genus in China may have played an important role in the emergence of this alphacoronavirus.
... Surprisingly, we are now even expecting to see the eradication of HCV from the planet by antiviral drugs. We have witnessed the frequent emergence of highly pathogenic coronaviruses since the year 2002, and yet more coronavirus outbreaks could potentially occur in the future due to spillover events [36]. Thus, preparing for future pandemics is not an option that we can afford any longer, and therefore, drug development for broadspectrum antiviral agents (or at least pan-coronavirus inhibitors) should be the main focus of efforts to respond to current and future global challenges. ...
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The placenta is a captivating multifunctional organ of fetal origin and plays an essential role during pregnancy by intimately connecting mother and baby. This study explicates placental pathology and information about 25 placentas collected from the mothers infected with novel coronavirus (SARS-COV-2). So far, congenital transmission of SARS-CoV-2 seems to be remarkably uncommon in spite of many cases of COVID-19 during pregnancy. Out of the 25 placental tissue samples collected, none has shown gene expression of SARS-CoV-2 when confirmed by RT-PCR. At the same time, nasal and throat swab samples collected from newborns of SARS-CoV-2-positive mothers correspondingly tested negative by RT-PCR. The shielding properties of placental barriers against viral infections from mothers to newborns remains a mystery. Major histopathological findings have been recorded as choriodecidual tissue with necrosis, intramural fibrin deposition, chorionic villi with fibrosis, and calcification. Moreover, although recent findings are insufficient to prove direct placental transmission of COVID-19, the abundance of angiotensin-converting enzymes-2 (ACE-2) on the placental surface could potentially contribute to unpleasant outcomes during pregnancy as SARSCoV- 2 gains access to human cells via ACE-2. Finally, the significance of these findings is vague and needs further study.
... Coronavirus evolution and emergence in new hosts is driven by different factors such as recombination, horizontal gene transfer, gene duplication and alternative open reading frames which expand their functional and adaptative capacity for the current and new host. During the high viral shedding season, bats are carriers of quasi-species pools of viruses which contribute to their genetic diversity and increase their potential to jump and emerge in a new species [56]. Due to the great genetic diversity observed at both sites as well as the important RNA bat CoV prevalence during the reproductive season, our sites could be potential hotspots of new CoV spillover and potential zoonotic emergence. ...
Background: Studies have linked bats to outbreaks in human populations such as SARS-CoV-1 and MERS-CoV and the ongoing SARS-CoV-2 pandemic. Method: We carried out a longitudinal survey from August 2020 to July 2021 at two sites in Zimbabwe with bat-human interactions: Magweto cave and Chirundu farm. A total 1732 and 1866 individual bat faecal samples were collected respectively. Coronaviruses and bat species were amplified using PCR systems respectively. Results: Analysis of the coronavirus sequences revealed a high genetic diversity and we identified different sub-viral groups in the Alphacoronavirus and Betacoronavirus genus. The established sub-viral groups fell within the described Alphacoronavirus sub-genera: Decacovirus, Duvinacovirus, Rhinacovirus, Setracovirus and Minunacovirus and for Betacoronavirus sub-genera: Sarbecoviruses, Merbecovirus and Hibecovirus. Our results showed an overall proportion for CoV positive PCR tests of 23.7% at Chirundu site, 16.5% and 38.9% at Magweto site for small insectivorous bats and Macronycteris gigas respectively. Conclusion: The higher risk of bat coronaviruses exposure for humans ranged from December to March in relation to higher viral shedding peaks of coronaviruses in the parturition, lactation and weaning months of the bat populations at both sites. We also highlight the need to further document viral infectious risk in human/domestic animal populations surrounding bat habitats in Zimbabwe.
... In 2013, a coronavirus (SHC014) with a close relationship to SARS-CoV, which uses human angiotensinconverting enzyme II (ACE2) in the receptor-binding domain of spike proteins to enter cells, was isolated from the horseshoe bat (Ge et al., 2013). Then, in 2015, using reverse genetics, a chimeric virus expressing this SHC014 spike in the backbone of a mouse-adapted SARS-CoV was created, which was shown to efficiently replicate in primary human airway cells by efficiently utilizing the SARS receptor, ACE2 (Menachery et al., 2015). This result was taken as proof of the existence of a virus that could cause a reemergence of SARS and was featured in Nature Review Microbiology's Research Highlights under the heading "The next SARS?" ...
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The dual-use risk of infectious disease research using enhanced potential pandemic pathogens (ePPP), particularly gain-of-function (GOF) research, has been debated since 2011. As of now, research is supported on the condition that the research plan is reviewed and the actual experiment is supervised. However, the kinds of research conducted and what benefits they have brought to our society have not been adequately verified. Nevertheless, due to the COVID-19 pandemic that began at the end of 2019 and caused numerous deaths and wide economic disruption, the importance of infectious disease control from an international perspective has been recognized. Although complete control of the pandemic is still far off, positive signs include generating epidemiological trends based on genome analysis, therapeutic drug and vaccine development, clinical patient management, and public health policy interventions. In this context, the time has come to reconsider the true significance of GOF research on ePPP and the state of research governance in the post-COVID-19 era. In particular, the risks of such research are clearer than before, whereas its benefits seem less apparent. In this paper, we summarize the history of discussions on such GOF research, its significance in the light of the current COVID-19 pandemic, and the direction we shall take in the future.
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With severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as an emergent human virus since December 2019, the world population is susceptible to coronavirus disease 2019 (COVID-19). SARS-CoV-2 has higher transmissibility than the previous coronaviruses, associated by the ribonucleic acid (RNA) virus nature with high mutation rate, caused SARS-CoV-2 variants to arise while circulating worldwide. Neutralizing antibodies are identified as immediate and direct-acting therapeutic against COVID-19. Single-domain antibodies (sdAbs), as small biomolecules with non-complex structure and intrinsic stability, can acquire antigen-binding capabilities comparable to conventional antibodies, which serve as an attractive neutralizing solution. SARS-CoV-2 spike protein attaches to human angiotensin-converting enzyme 2 (ACE2) receptor on lung epithelial cells to initiate viral infection, serves as potential therapeutic target. sdAbs have shown broad neutralization towards SARS-CoV-2 with various mutations, effectively stop and prevent infection while efficiently block mutational escape. In addition, sdAbs can be developed into multivalent antibodies or inhaled biotherapeutics against COVID-19.
This essay explores the ways in which notions of ‘expert’-driven authenticity are being interrogated in the post-COVID-19 media sphere. I argue that the intensification of pathogenic virality has instantiated a generative ‘contamination’ of scientific disciplines such as immunology and virology with the networked openness of digital image cultures. It is through this contamination that we are able to see media forms as central to viral matter and not merely as repositories of its causes and effects. It is in the actions of a growing community of networked media user-producers and amateur scientists that a new lexicon of authenticity and truth can be imagined for our post-pandemic world.
Coccidioides immitis and Coccidioides posadasii are the etiological agents of coccidioidomycosis (Valley fever [VF]). Disease manifestation ranges from mild pneumonia to chronic or extrapulmonary infection. If diagnosis is delayed, the risk of severe disease increases. In this report, we investigated the intersection of pathogen, host, and environment for VF cases in Northern Arizona (NAZ), where the risk of acquiring the disease is much lower than in Southern Arizona. We investigated reported cases and assessed pathogen origin by comparing genomes of NAZ clinical isolates to isolates from other regions. Lastly, we surveyed regional soils for presence of Coccidioides. We found that cases of VF increased in NAZ in 2019, and Coccidioides NAZ isolates are assigned to Arizona populations using phylogenetic inference. Importantly, we detected Coccidioides DNA in NAZ soil. Given recent climate modeling of the disease that predicts that cases will continue to increase throughout the region, and the evidence presented in this report, we propose that disease awareness outreach to clinicians throughout the western United States is crucial for improving patient outcomes, and further environmental sampling across the western U.S. is warranted. IMPORTANCE Our work is the first description of the Valley fever disease triangle in Northern Arizona, which addresses the host, the pathogen, and the environmental source in the region. Our data suggest that the prevalence of diagnosed cases rose in 2019 in this region, and some severe cases necessitate hospitalization. We present the first evidence of Coccidioides spp. in Northern Arizona soils, suggesting that the pathogen is maintained in the local environment. Until disease prevention is an achievable option via vaccination, we predict that incidence of Valley fever will rise in the area. Therefore, enhanced awareness of and surveillance for coccidioidomycosis is vital to community health in Northern Arizona.
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Unlabelled: The receptor binding domain (RBD) of the spike (S) glycoprotein of severe acute respiratory syndrome coronavirus (SARS-CoV) is a major target of protective immunity in vivo. Although a large number of neutralizing antibodies (nAbs) have been developed, it remains unclear if a single RBD-targeting nAb or two in combination can prevent neutralization escape and, if not, attenuate viral virulence in vivo. In this study, we used a large panel of human nAbs against an epitope that overlaps the interface between the RBD and its receptor, angiotensin-converting enzyme 2 (ACE2), to assess their cross-neutralization activities against a panel of human and zoonotic SARS-CoVs and neutralization escape mutants. We also investigated the neutralization escape profiles of these nAbs and evaluated their effects on receptor binding and virus fitness in vitro and in mice. We found that some nAbs had great potency and breadth in neutralizing multiple viral strains, including neutralization escape viruses derived from other nAbs; however, no single nAb or combination of two blocked neutralization escape. Interestingly, in mice the neutralization escape mutant viruses showed either attenuation (Urbani background) or increased virulence (GD03 background) consistent with the different binding affinities between their RBDs and the mouse ACE2. We conclude that using either single nAbs or dual nAb combinations to target a SARS-CoV RBD epitope that shows plasticity may have limitations for preventing neutralization escape during in vivo immunotherapy. However, RBD-directed nAbs may be useful for providing broad neutralization and prevention of escape variants when combined with other nAbs that target a second conserved epitope with less plasticity and more structural constraint. Importance: The emergence of severe acute respiratory syndrome coronavirus (SARS-CoV) in 2002 and Middle East respiratory syndrome coronavirus (MERS-CoV) in 2012 has resulted in severe human respiratory disease with high death rates. Their zoonotic origins highlight the likelihood of reemergence or further evolution into novel human coronavirus pathogens. Broadly neutralizing antibodies (nAbs) that prevent infection of related viruses represent an important immunostrategy for combating coronavirus infections; however, for this strategy to succeed, it is essential to uncover nAb-mediated escape pathways and to pioneer strategies that prevent escape. Here, we used SARS-CoV as a research model and examined the escape pathways of broad nAbs that target the receptor binding domain (RBD) of the virus. We found that neither single nAbs nor two nAbs in combination blocked escape. Our results suggest that targeting conserved regions with less plasticity and more structural constraint rather than the SARS-CoV RBD-like region(s) should have broader utility for antibody-based immunotherapy.
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Without an approved vaccine or treatment, Ebola outbreak management has been limited to palliative care and barrier methods to prevent transmission. These approaches, however, have yet to end the 2014 outbreak of Ebola after its prolonged presence in West Africa. Here we show that a combination of monoclonal antibodies (ZMapp), optimized from two previous antibody cocktails, is able to rescue 100% of rhesus macaques when treatment is initiated up to 5 days post-challenge. High fever, viraemia and abnormalities in blood count and blood chemistry were evident in many animals before ZMapp intervention. Advanced disease, as indicated by elevated liver enzymes, mucosal haemorrhages and generalized petechia could be reversed, leading to full recovery. ELISA and neutralizing antibody assays indicate that ZMapp is cross-reactive with the Guinean variant of Ebola. ZMapp exceeds the efficacy of any other therapeutics described so far, and results warrant further development of this cocktail for clinical use.
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Unlabelled: Although many severe acute respiratory syndrome-like coronaviruses (SARS-like CoVs) have been identified in bats in China, Europe, and Africa, most have a genetic organization significantly distinct from human/civet SARS CoVs in the receptor-binding domain (RBD), which mediates receptor binding and determines the host spectrum, resulting in their failure to cause human infections and making them unlikely progenitors of human/civet SARS CoVs. Here, a viral metagenomic analysis of 268 bat rectal swabs collected from four counties in Yunnan Province has identified hundreds of sequences relating to alpha- and betacoronaviruses. Phylogenetic analysis based on a conserved region of the RNA-dependent RNA polymerase gene revealed that alphacoronaviruses had diversities with some obvious differences from those reported previously. Full genomic analysis of a new SARS-like CoV from Baoshan (LYRa11) showed that it was 29,805 nucleotides (nt) in length with 13 open reading frames (ORFs), sharing 91% nucleotide identity with human/civet SARS CoVs and the most recently reported SARS-like CoV Rs3367, while sharing 89% with other bat SARS-like CoVs. Notably, it showed the highest sequence identity with the S gene of SARS CoVs and Rs3367, especially in the RBD region. Antigenic analysis showed that the S1 domain of LYRa11 could be efficiently recognized by SARS-convalescent human serum, indicating that LYRa11 is a novel virus antigenically close to SARS CoV. Recombination analyses indicate that LYRa11 is likely a recombinant descended from parental lineages that had evolved into a number of bat SARS-like CoVs. Importance: Although many severe acute respiratory syndrome-like coronaviruses (SARS-like CoVs) have been discovered in bats worldwide, there are significant different genic structures, particularly in the S1 domain, which are responsible for host tropism determination, between bat SARS-like CoVs and human SARS CoVs, indicating that most reported bat SARS-like CoVs are not the progenitors of human SARS CoV. We have identified diverse alphacoronaviruses and a close relative (LYRa11) to SARS CoV in bats collected in Yunnan, China. Further analysis showed that alpha- and betacoronaviruses have different circulation and transmission dynamics in bat populations. Notably, full genomic sequencing and antigenic study demonstrated that LYRa11 is phylogenetically and antigenically closely related to SARS CoV. Recombination analyses indicate that LYRa11 is a recombinant from certain bat SARS-like CoVs circulating in Yunnan Province.
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Cross-species transmission of zoonotic coronaviruses (CoVs) can result in pandemic disease outbreaks. Middle East respiratory syndrome CoV (MERS-CoV), identified in 2012, has caused 182 cases to date, with ~43% mortality, and no small animal model has been reported. MERS-CoV and Pipistrellus bat coronavirus (BtCoV) strain HKU5 of Betacoronavirus (β-CoV) subgroup 2c share >65% identity at the amino acid level in several regions, including nonstructural protein 5 (nsp5) and the nucleocapsid (N) protein, which are significant drug and vaccine targets. BtCoV HKU5 has been described in silico but has not been shown to replicate in culture, thus hampering drug and vaccine studies against subgroup 2c β-CoVs. We report the synthetic reconstruction and testing of BtCoV HKU5 containing the severe acute respiratory syndrome (SARS)-CoV spike (S) glycoprotein ectodomain (BtCoV HKU5-SE). This virus replicates efficiently in cell culture and in young and aged mice, where the virus targets airway and alveolar epithelial cells. Unlike some subgroup 2b SARS-CoV vaccines that elicit a strong eosinophilia following challenge, we demonstrate that BtCoV HKU5 and MERS-CoV N-expressing Venezuelan equine encephalitis virus replicon particle (VRP) vaccines do not cause extensive eosinophilia following BtCoV HKU5-SE challenge. Passage of BtCoV HKU5-SE in young mice resulted in enhanced virulence, causing 20% weight loss, diffuse alveolar damage, and hyaline membrane formation in aged mice. Passaged virus was characterized by mutations in the nsp13, nsp14, open reading frame 5 (ORF5) and M genes. Finally, we identified an inhibitor active against the nsp5 proteases of subgroup 2c β-CoVs. Synthetic-genome platforms capable of reconstituting emerging zoonotic viral pathogens or their phylogenetic relatives provide new strategies for identifying broad-based therapeutics, evaluating vaccine outcomes, and studying viral pathogenesis.
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The 2002-3 pandemic caused by severe acute respiratory syndrome coronavirus (SARS-CoV) was one of the most significant public health events in recent history. An ongoing outbreak of Middle East respiratory syndrome coronavirus suggests that this group of viruses remains a key threat and that their distribution is wider than previously recognized. Although bats have been suggested to be the natural reservoirs of both viruses, attempts to isolate the progenitor virus of SARS-CoV from bats have been unsuccessful. Diverse SARS-like coronaviruses (SL-CoVs) have now been reported from bats in China, Europe and Africa, but none is considered a direct progenitor of SARS-CoV because of their phylogenetic disparity from this virus and the inability of their spike proteins to use the SARS-CoV cellular receptor molecule, the human angiotensin converting enzyme II (ACE2). Here we report whole-genome sequences of two novel bat coronaviruses from Chinese horseshoe bats (family: Rhinolophidae) in Yunnan, China: RsSHC014 and Rs3367. These viruses are far more closely related to SARS-CoV than any previously identified bat coronaviruses, particularly in the receptor binding domain of the spike protein. Most importantly, we report the first recorded isolation of a live SL-CoV (bat SL-CoV-WIV1) from bat faecal samples in Vero E6 cells, which has typical coronavirus morphology, 99.9% sequence identity to Rs3367 and uses ACE2 from humans, civets and Chinese horseshoe bats for cell entry. Preliminary in vitro testing indicates that WIV1 also has a broad species tropism. Our results provide the strongest evidence to date that Chinese horseshoe bats are natural reservoirs of SARS-CoV, and that intermediate hosts may not be necessary for direct human infection by some bat SL-CoVs. They also highlight the importance of pathogen-discovery programs targeting high-risk wildlife groups in emerging disease hotspots as a strategy for pandemic preparedness.
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Revolutionary advances in DNA sequencing technology are radically changing the approach for studying and characterizing the microbial world. The sequencing of a microbial genome, which can now be achieved in preliminary form in hours, provides a wealth of information about the functional potential of the organism, its evolutionary relationships with other organisms, and clues about niche adaptation, and without the need for microbial cultivation or isolation.1 Likewise, so-called shotgun or metagenomic sequencing, which is the high-throughput simultaneous sequencing of random fragments from complex mixes of different genomes, provides insights into the potential activities of a microbial community, possible interactions between microbial community members, and the nature of their relationships with their environment (eg, a human host).
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The severe acute respiratory syndrome coronavirus accessory protein ORF6 antagonizes interferon signaling by blocking karyopherin-mediated nuclear import processes. Viral nuclear import antagonists, expressed by several highly pathogenic RNA viruses, likely mediate pleiotropic effects on host gene expression, presumably interfering with transcription factors, cytokines, hormones, and/or signaling cascades that occur in response to infection. Using bioinformatic and systems biology approaches, we evaluated the impact of nuclear import antagonism on host expression networks using human lung epithelial cells infected with either wild type virus or a mutant that does not express ORF6 protein. Microarray analysis revealed significant changes in differential gene expression with approximately twice as many upregulated genes in the mutant virus samples by 48 hours post-infection, despite identical viral titers. Our data demonstrate that ORF6 protein expression attenuates the activity of numerous karyopherin-dependent host transcription factors (VDR, CREB1, SMAD4, p53, EpasI, and Oct3/4), which are critical for establishing antiviral responses and regulating key host responses during virus infection. Results were confirmed by proteomic and chromatin immunoprecipitation assay analyses and in parallel microarray studies using infected primary human airway epithelial cell cultures. The data strongly support the hypothesis that viral antagonists of nuclear import actively manipulate host responses in specific hierarchical patterns, contributing to viral pathogenic potential in vivo. Importantly, these studies and modeling approaches not only provide templates for evaluating virus antagonism of nuclear import processes, but revealed candidate cellular genes and pathways that may significantly influence disease outcomes following severe acute respiratory syndrome coronavirus infection in vivo.
Several new viral respiratory tract infectious diseases with epidemic potential that threaten global health security have emerged in the past 15 years. In 2003, WHO issued a worldwide alert for an unknown emerging illness, later named severe acute respiratory syndrome (SARS). The disease caused by a novel coronavirus (SARS-CoV) rapidly spread worldwide, causing more than 8000 cases and 800 deaths in more than 30 countries with a substantial economic impact. Since then, we have witnessed the emergence of several other viral respiratory pathogens including influenza viruses (avian influenza H5N1, H7N9, and H10N8; variant influenza A H3N2 virus), human adenovirus-14, and Middle East respiratory syndrome coronavirus (MERS-CoV). In response, various surveillance systems have been developed to monitor the emergence of respiratory-tract infections. These include systems based on identification of syndromes, web-based systems, systems that gather health data from health facilities (such as emergency departments and family doctors), and systems that rely on self-reporting by patients. More effective national, regional, and international surveillance systems are required to enable rapid identification of emerging respiratory epidemics, diseases with epidemic potential, their specific microbial cause, origin, mode of acquisition, and transmission dynamics.
Two novel coronaviruses have emerged in humans in the twenty-first century: severe acute respiratory syndrome coronavirus (SARS-CoV) and Middle East respiratory syndrome coronavirus (MERS-CoV), both of which cause acute respiratory distress syndrome (ARDS) and are associated with high mortality rates. There are no clinically approved vaccines or antiviral drugs available for either of these infections; thus, the development of effective therapeutic and preventive strategies that can be readily applied to new emergent strains is a research priority. In this Review, we describe the emergence and identification of novel human coronaviruses over the past 10 years, discuss their key biological features, including tropism and receptor use, and summarize approaches for developing broadly effective vaccines.
Receptor recognition is a major determinant of the host range, cross-species infections, and pathogenesis of the severe acute respiratory syndrome coronavirus (SARS-CoV). A defined receptor-binding domain (RBD) in the SARS-CoV spike protein specifically recognizes its host receptor, angiotensin-converting enzyme 2 (ACE2). This article reviews the latest knowledge about how RBDs from different SARS-CoV strains interact with ACE2 from several animal species. Detailed research on these RBD/ACE2 interactions has established important principles on host receptor adaptations, cross-species infections, and future evolution of SARS-CoV. These principles may apply to other emerging animal viruses, including the recently emerged Middle East respiratory syndrome coronavirus (MERS-CoV). This paper forms part of a series of invited articles in Antiviral Research on "From SARS to MERS: 10years of research on highly pathogenic human coronaviruses".