COVID-19: Significance of Fc properties and functions in antibody responses against SARS-CoV-2

项目摘要/摘要 新冠肺炎大流行是由SARS-CoV-2引起的，这种新型冠状病毒在 2019年11月至12月，已造成全球数百万人死亡。在美国，疫情正在影响 数以百万计的生命。退伍军人医院，包括布朗克斯的詹姆斯·J·彼得斯退伍军人医疗中心(JJP VAMC)， 纽约，已经迅速做出反应，为退伍军人和员工提供护理。退伍军人通常比 美国普通人口，使他们极易患上严重疾病。新冠肺炎疫苗也是 最初分发给老年人和其他高危人群。这为退伍军人管理局提供了一个独特的机会 研究SARS-CoV-2在最易感染人群中的感染和接种情况。 这项VA优点应用程序建议研究引起的抗体(Abs)对 疫苗接种或感染后SARS-CoV-2刺突蛋白及其受体结合域(RBD)。在……里面 特别是，我们将检查尚未很好理解的抗体Fc的属性和功能，以及 存在于血液和唾液中，作为病毒进入粘膜部位的抗体的替代品。建议的研究已完成 根据我们已发表的初步结果显示检测到不同的免疫球蛋白(Ig)亚型 新冠肺炎恢复期患者唾液与血浆中抗SARS-CoV-2尖峰和RBD及疫苗的研究 收件人。有趣的是，我们的初步数据表明，唾液中的特异性免疫球蛋白亚型缺乏相关性。 与来自感染和接种疫苗的受试者的血浆进行比较。数据进一步显示了第一个C1q的结合 经典补体级联中的成分，与感染和接种的受试者的抗体结合。值得注意的是， 唾液和血浆中抗体的C1q结合活性相关性较差，为 感染和免疫诱导的粘膜和循环中抗棘突抗体Fc功能的差异。 为了进一步研究抗SARS-CoV-2抗体的Fc性质和功能，我们假设 Fc亚型和糖基化是Fc依赖的抗体保护功能的关键决定因素 对阵新冠肺炎。一个研究团队，其中包括具有抗体和病毒专业知识的研究专家 免疫学(PI：JJP VAMC的Catarina Hioe；合作者：Susan Zolla-Pazner，Chitra Upadhyay，Ray Alvarez在西奈山医学院/MSSM)，质谱学和多糖生物学专家(回族 约翰霍普金斯大学的张)和一名传染病临床医生(Co-I：JJP VAMC的Juan Bandres)将会工作 共同检验这一假说。我们将利用我们在抗艾滋病毒信封方面的广泛专业知识 糖蛋白和我们过去一年研究SARS-CoV-2抗体反应的经验。在目标1中， 我们将收集纵向血浆和唾液样本，以确定抗体的亚型和持久性。 新冠肺炎门诊、住院患者及正常人不同体液中的SPEK和RBD 新冠肺炎核糖核酸疫苗未受感染的接受者。目标2将评估Fc区的糖链结构 SARS-CoV-2感染者和疫苗接种者抗尖峰抗体的检测AIM 3将评估FC中介的 这些抗体介导的破坏病毒颗粒和病毒感染细胞的活性，即补体 结合/激活和FcɣR介导的信号、细胞毒性和吞噬作用。不同Ig亚型和不同类型的ABS 对于实验修饰的Fc，还将检查其Fc依赖的活性。建议数 研究将产生对推进改进的基于抗体的诊断武器库的开发至关重要的数据， 新冠肺炎的预防和治疗。

Project Summary/Abstract The COVID-19 pandemic, which is caused by SARS-CoV-2, a novel coronavirus first detected in November-December 2019, has inflicted millions of deaths worldwide. In the US, the outbreak is affecting millions of lives. The VA hospitals, including the James J. Peters VA Medical Center (JJP VAMC) in the Bronx, NY, have responded promptly to provide care to Veterans and employees. Veterans are typically older than the general US population, making them highly susceptible to severe disease. COVID-19 vaccines are also distributed initially to the elderly and other high-risk individuals. This provides the VA a unique opportunity to study SARS-CoV-2 infection and vaccination in the most vulnerable individuals. This VA Merit application proposes to investigate the protective role of antibodies (Abs) elicited against the SARS-CoV-2 spike protein and its receptor-binding domain (RBD) following vaccination or infection. In particular, we will examine the Ab Fc properties and functions that are not well understood and the Abs that are present in blood and in saliva as a proxy of Abs at the mucosal site of virus entry. The proposed study is built upon our published and preliminary results showing the detection of different immunoglobulin (Ig) isotypes against SARS-CoV-2 spike and RBD in saliva vs plasma of convalescent COVID-19 patients and vaccine recipients. Interestingly, our preliminary data indicate a lack of correlation of spike-specific Ig isotypes in saliva vs plasma from infected and vaccinated subjects. The data further show the binding of C1q, the first component in the classical complement cascade, to Abs from both infected and vaccinated subjects. Notably, the C1q binding activities of Abs in saliva vs plasma correlated poorly, offering the initial evidence for differential Fc functions of mucosal vs circulating anti-spike Abs elicited by infection and vaccination. To investigate further the Fc properties and functions of Abs against SARS-CoV-2, we hypothesize that Fc isotype and glycosylation are the key determinants of Fc-dependent Ab functions in protection against COVID-19. A research team that include research specialists with expertise in Abs and viral immunology (PI: Catarina Hioe at JJP VAMC; collaborators: Susan Zolla-Pazner, Chitra Upadhyay, Ray Alvarez at Mount Sinai School of Medicine/MSSM), an expert in mass spectrometry and glycan biology (Hui Zhang at Johns Hopkins Univ), and an infectious disease clinician (Co-I: Juan Bandres at JJP VAMC) will work together to test this hypothesis. We will leverage our extensive expertise in Abs against HIV envelope glycoprotein and our experience investigating Ab responses against SARS-CoV-2 in the past year. In Aim 1, we will collect longitudinal plasma and saliva samples to determine the isotypes and durability of Abs against spike and RBD in different bodily fluids of ambulatory and hospitalized COVID-19 patients and healthy uninfected recipients of COVID-19 RNA vaccines. Aim 2 will evaluate the glycan structures on the Fc regions of Abs against spike from SARS-CoV-2-infected and vaccinated subjects. Aim 3 will assess the Fc-mediated activities that these Abs mediate to destroy virus particles and virus-infected cells, i.e. complement binding/activation and FcɣR-mediated signaling, cytotoxicity, and phagocytosis. Abs of different Ig isotypes and with experimentally modified Fc glycans will also be examined for their Fc-dependent activities. The proposed study will produce data critical to advance the development of improved Ab-based arsenals for diagnostics, prophylactics, and therapeutics against COVID-19.