COVID19: Respiratory SARS-CoV-2 seroprevalence and the association of humoral immune responses with clinical outcomes in veterans and employees in the Cleveland VA Medical Center

SARS-CoV-2的全球大流行对卫生保健工作者和研究人员提出了迫切的要求。 在4月3日至5月1日期间，全球COVID 19病例从约100万增至300多万，几乎增加了两倍。 万随着SARS-CoV-2在秋季再次出现的可能性， 具有本质意义本申请旨在研究退伍军人对SARS-CoV-2的体液免疫应答 以及克利夫兰退伍军人医疗中心的员工该提案有三个目标。目标1）快速发展， 高通量检测COVID 19中SARS-CoV-2蛋白的总抗体和功能抗体 感染的人。目的一：建立一种基于磁珠的抗体检测方法 在一个血清样本中对多达50种不同的SARS-CoV-2表位的反应。该分析还将能够 检测干扰SARS刺突蛋白受体结合结构域（RBD）结合的Ab- CoV-2与其受体ACE 2。可阻断肺上皮细胞上RBD和ACE 2之间结合的抗体 细胞将阻止病毒进入并可能中和。目的2）确定是否有强大的体液免疫和 较高的中和抗体滴度保护VA医疗保健员工免受临床COVID 19的影响， 低水平或无SAR 2-CoV-2特异性抗体。在aim 2中，我们将使用快速抗体测试来筛选 克利夫兰弗吉尼亚州的卫生保健员工在高风险感染COVID 19（第一反应，紧急 部门工作人员、重症监护室工作人员、COVID 19病房工作人员）。我们会要求他们提供血清样本 检测COVID-19抗体阳性，以更深入地检测SARS-CoV-2抗体反应。我们将研究 一般Ab滴度、中和Ab滴度和抗体同种型。如果COVID 19在秋季卷土重来， 我们将确定那些具有强烈体液反应的卫生保健工作人员是否能更好地防止再感染， 感染者的抗体反应弱或无抗体反应的雇员。目的3）研究 COVID 19诱导的淋巴细胞减少症，能够产生体液免疫应答。年纪大了，非典- CoV-1和SARS-COV-2感染都与白色血细胞减少或淋巴细胞减少有关。在 目的3我们将检测淋巴细胞减少症对COVID 19的体液Ab应答的发展的影响。 我们预计，这些人与严重的淋巴细胞减少症将有很少的T滤泡辅助细胞在他们的淋巴 节点，这将导致不良的Ab亲和力成熟、同种型转换和B细胞记忆发育。在 总之，该项目的结果将提供一种快速的SARS-CoV-2特异性血清检测方法，能够检测 中和抗体，可用于筛选VA医护人员暴露于SARS-CoV-2。我们将 调查感染了高风险卫生保健工作者的体液抗体反应， COVID 19，并试图确定什么是保护免受再感染，如果有一个复苏， COVID 19在秋天最后，我们将了解B细胞亲和力成熟、同种型转换 以及B细胞记忆和中和抗体滴度的产生，并确定淋巴细胞减少症如何在 对COVID 19的体液免疫功能障碍。这些知识将有助于开发更好的治疗方法 未来的疫苗

The global pandemic of SARS-CoV-2 is placing urgent demands on health care workers and researchers. Between April 3rd and May 1st global cases of COVID19 nearly tripled from approximately 1 million to over 3 million. With the possibility of a reemergence of SARS-CoV-2 in the fall, rapid specific antibody assays are essential. This application proposes to investigate the humoral immune responses to SARS-CoV-2 in veterans and employees at the Cleveland VA Medical Center. The proposal has three aims. Aim 1) To develop rapid, high throughput assays to measure total and functional antibodies to SARS-CoV-2 proteins in COVID19 infected individuals. In aim 1, we will establish a magnet bead-based assay that can detect antibody (Ab) responses to up to 50 different epitopes of SARS-CoV-2 in one serum sample. This assay will also be able to detect Abs that interfere with the binding of the receptor binding domain (RBD) of the spike protein of SARS- CoV-2 to its receptor, ACE2. Antibodies that can block binding between the RBD and ACE2 on lung epithelial cells will prevent viral entry and will likely be neutralizing. Aim 2) To determine if robust humoral immunity and higher neutralizing Ab titers protect VA health care employees from clinical COVID19 compared to their colleagues with low or no SAR2-CoV-2 specific antibodies. In aim 2 we will use a rapid antibody test to screen Cleveland VA health care employees at high-risk for infection with COVID19 (first responders, emergency department staff, intensive care unit staff, COVID19 ward staff). We will ask for a serum sample from those that are Ab positive for COVID19 to examine the SARS-CoV-2 Ab response in more depth. We will examine general Ab titers, neutralizing Ab titers, and antibody isotypes. If there is a resurgence of COVID19 in the fall, we will determine if those health care employees with a robust humoral response are better protected from re- infection than those employees who had a weak or no Ab response. Aim 3) To examine the association of COVID19-induced lymphopenia with the ability to generate a humoral immune response. Older age, SARS- CoV-1 and SARS-COV-2 infection are all associated with a decrease of white blood cells or lymphopenia. In aim 3 we will examine the effect of lymphopenia on the development of the humoral Ab response to COVID19. We expect that those individuals with severe lymphopenia will have few T follicular helper cells in their lymph nodes and this will lead to poor Ab affinity maturation, isotype switching, and B cell memory development. In summary, results from this project will provide a rapid SARS-CoV-2 specific serum assay able to detect neutralizing Ab that can be used to screen VA healthcare workers for exposure to SARS-CoV-2. We will investigate the humoral antibody responses of high-risk health care employees that were infected with COVID19 and try to determine what constitutes protection from re-infection if there is a resurgence of COVID19 in the fall. Lastly, we will gain an understanding of the B cell affinity maturation, isotype switching and generation of B cell memory and neutralizing Ab titers and determine how lymphopenia may play a role in the dysfunction of humoral immunity to COVID19. This knowledge will aid in development of better treatment and future vaccines.