Critical neutralizing domain-based vaccines against new SARS-like virus hCoV-EMC

摘要 一种新的人类冠状病毒hCoV-EMC最近在中东地区被发现。确实是 据报告导致严重急性呼吸系统综合症(SARS)样疾病，已造成5人死亡 自2012年6月以来，已有5人死亡，4人患病。因为人类冠状病毒-EMC是遗传的 与SARS冠状病毒有关，SARS是致命SARS的病原体，造成774人死亡 2003年爆发期间的8,098例感染病例，引起了人们对 这种致命疾病的潜在大流行传播。因此，开发疫苗以预防 迫切需要控制hCoV-EMC感染的潜在暴发。我们之前已经展示了 SARS-CoV S蛋白(S)S1亚基受体结合域 关键中和域(CND)和基于RBD/CND的亚单位疫苗可以 SARS冠状病毒感染小鼠诱导有效的中和抗体应答和保护作用 动物模型。通过对SARS冠状病毒和人冠状病毒S蛋白序列的比较分析-- Emc，我们发现hCoV-emc S蛋白S1亚基还含有一个显示出 核心结构与SARS冠状病毒S蛋白中的RBD非常相似。我们还发现，一个 含人冠状病毒截短胞外结构域的重组蛋白与Fc的融合 诱导的S特异性抗体具有中和活性，提示人冠状病毒-EMC S蛋白 确实含有CND(S)。因此我们假设CND(S)可以从 人冠状病毒-EMC S蛋白，以此为基础的有效疫苗具有较强的诱导能力 抗hCoV-EMC感染的中和抗体应答和保护性免疫 可以被开发出来。这项建议的具体目的是：1)将新城疫(S)与人型冠状病毒- EMC S蛋白及其亚基，2)设计基于CND亚单位的hCoV-EMC疫苗，3)优化 用选定的hCoV-EMC疫苗接种动物的免疫方案 候选；4)评价所选hCoV-EMC疫苗的体内保护性免疫 在动物模型中抵抗病毒挑战的候选人。建议的长期目标是 研究旨在开发一种有效、安全的基于CND的亚单位疫苗，以对抗新城疫 确定了可能导致未来在人类中爆发的类似SARS的病毒hCoV-EMC。

Abstract A novel human coronavirus, hCoV-EMC, was recently identified in the Middle East. It was reported to cause severe acute respiratory syndrome (SARS)-like disease, having killed 5 persons and sickened 4 others since June of 2012. Because hCoV-EMC is genetically related to SARS-CoV, the causative agent of the deadly SARS that killed 774 people among 8,098 infected cases during the 2003 outbreak, it has raised great concerns about the potential pandemic spread of this lethal disease. Therefore, developing vaccines to prevent the potential outbreak of hCoV-EMC infection is urgently needed. We have previously shown that the receptor-binding domain (RBD) of SARS-CoV spike (S) protein S1 subunit contains critical neutralizing domain (CND) and that the subunit vaccine based on the RBD/CND can induce potent neutralizing antibody responses and protection against SARS-CoV infection in animal models. By comparing and analyzing the S protein sequences of SARS-CoV and hCoV- EMC, we found that hCoV-EMC S protein S1 subunit also contains a region that exhibited a core structure very similar to that of RBD in SARS-CoV S protein. We also found that a recombinant protein containing the truncated ectodomain of hCoV-EMC S protein fused to Fc induced S-specific antibodies with neutralizing activity, suggesting that hCoV-EMC S protein does contain CND(s). We therefore hypothesize that CND(s) can be identified from the hCoV-EMC S protein, based which an effective vaccine with ability to elicit strong neutralizing antibody responses and protective immunity against hCoV-EMC infection can be developed. The specific aims of this proposal are to: 1) identify CND(s) from hCoV- EMC S protein and its subunits, 2) design CND-based subunit hCoV-EMC vaccines, 3) optimize immunization regimens for vaccination of animals with a selected hCoV-EMC vaccine candidate, and 4) evaluate the in vivo protective immunity of the selected hCoV-EMC vaccine candidate against viral challenge in an animal model. The long-term goal of the proposed study is to develop an effective and safe CND-based subunit vaccine against the newly identified SARS-like virus hCoV-EMC that may cause a future outbreak in humans.