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 populations1. Using the SARS-CoV reverse genetics system2, 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.

Main

The emergence of SARS-CoV heralded a new era in the cross-species transmission of severe respiratory illness with globalization leading to rapid spread around the world and massive economic impact3,4. Since then, several strains—including influenza A strains H5N1, H1N1 and H7N9 and MERS-CoV—have emerged from animal populations, causing considerable disease, mortality and economic hardship for the afflicted regions5. Although public health measures were able to stop the SARS-CoV outbreak4, recent metagenomics studies have identified sequences of closely related SARS-like viruses circulating in Chinese bat populations that may pose a future threat1,6. However, sequence data alone provides minimal insights to identify and prepare for future prepandemic viruses. Therefore, to examine the emergence potential (that is, the potential to infect humans) of circulating bat CoVs, we built a chimeric virus encoding a novel, zoonotic CoV spike protein—from the RsSHC014-CoV sequence that was isolated from Chinese horseshoe bats1—in the context of the SARS-CoV mouse-adapted backbone. The hybrid virus allowed us to evaluate the ability of the novel spike protein to cause disease independently of other necessary adaptive mutations in its natural backbone. Using this approach, we characterized CoV infection mediated by the SHC014 spike protein in primary human airway cells and in vivo, and tested the efficacy of available immune therapeutics against SHC014-CoV. Together, the strategy translates metagenomics data to help predict and prepare for future emergent viruses.

抽象的

嚴重急性呼吸綜合徵冠狀病毒 (SARS-CoV) 和中東呼吸綜合徵 (MERS)-CoV 的出現凸顯了導致人類爆發的跨物種傳播事件的威脅。在這裡，我們研究了一種 SARS 樣病毒 SHC014-CoV 的疾病潛力，該病毒目前在中國馬蹄蝠種群1 中傳播。使用 SARS-CoV 反向遺傳學系統2，我們生成並表徵了一種嵌合病毒，該病毒在小鼠適應的 SARS-CoV 骨架中表達蝙蝠冠狀病毒 SHC014 的尖峰。結果表明，在野生型骨架中編碼 SHC014 尖峰的 2b 組病毒可以有效地使用 SARS 受體人血管緊張素轉化酶 II (ACE2) 的多個直向同源物，在原代人氣道細胞中有效複製，並實現與流行病相當的體外滴度SARS-CoV 病毒株。此外，體內實驗證明嵌合病毒在小鼠肺中的複製具有顯着的發病機制。對現有的基於 SARS 的免疫治療和預防方法的評估顯示療效不佳；使用新型刺突蛋白，單克隆抗體和疫苗方法均未能中和並保護其免受 CoV 感染。在這些發現的基礎上，我們重新合成了一種傳染性全長 SHC014 重組病毒，並在體外和體內證明了強大的病毒複製。我們的工作表明，目前在蝙蝠種群中傳播的病毒存在重新出現 SARS-CoV 的潛在風險。

主要的

SARS-CoV 的出現預示着嚴重呼吸道疾病跨物種傳播的新時代，全球化導致了全球範圍內的快速傳播和巨大的經濟影響3、4。從那時起，動物種群中出現了幾種毒株，包括甲型流感毒株 H5N1、H1N1 和 H7N9 以及 MERS-CoV，給受災地區造成了相當大的疾病、死亡率和經濟困難5。儘管公共衛生措施能夠阻止 SARS-CoV 的爆發4，但最近的宏基因組學研究已經確定了在中國蝙蝠種群中傳播的密切相關的 SARS 樣病毒序列，這些病毒可能對未來構成威脅1 , 6. 然而，僅憑序列數據就無法識別和準備未來的大流行前病毒。因此，為了檢查循環蝙蝠 CoV 的出現潛力（即感染人類的潛力），我們構建了一種嵌合病毒，該病毒編碼一種新型的人畜共患 CoV 刺突蛋白——來自從中國馬蹄蝠中分離的 RsSHC014-CoV 序列1 ——在 SARS-CoV 小鼠適應骨幹的背景下。雜交病毒使我們能夠獨立於其天然骨架中其他必要的適應性突變來評估新型刺突蛋白引起疾病的能力。使用這種方法，我們在原代人類呼吸道細胞和體內表徵了由 SHC014 刺突蛋白介導的 CoV 感染，並測試了現有免疫療法對 SHC014-CoV 的功效。該策略共同轉化宏基因組學數據，以幫助預測和準備未來出現的病毒。