Project 2: B Cells

项目2：概要 产生血清和粘膜抗体的B细胞和浆细胞群将最终决定 个体对SARS-CoV-2感染的体液免疫反应的有效性和持续时间。我们将 在博伊德实验室中，我使用几种相互支持的策略来分析这些细胞：单B细胞表型，B 细胞受体（BCR）深度测序和用DNA条形码化抗原测定抗原特异性 四聚体;大部分B细胞免疫球蛋白基因库测序;以及从 抗原特异性B细胞。在互补策略中，Jardetzky实验室将利用酵母展示文库， 患者来源的单链抗体可变片段（ScFv）富集天然重链-轻链配对， 确定每个患者数百至数千个抗原特异性克隆的抗原特异性。在纵向 外周血样本和鼻活检样本，我们将彻底表征抗原特异性B细胞 患者对SARS-CoV-2的反应中的克隆。我们假设有了这些数据我们就能确定 B细胞对SARS-CoV-2的克隆应答的哪些特征与COVID-19疾病的差异相关 严重程度和按年龄、性别、种族和既存疾病分层的人群组之间的差异 条件，或在检查点阻断治疗的背景下免疫失调。我们进一步假设 对记忆B细胞群和血清学反应的分析可以预测哪些个体 将对再次暴露于SARS-CoV-2有更持久的体液保护作用。最后，我们将评估B 与接种疫苗相比，自然感染刺激的细胞应答，从Covaxx肽开始， 基于疫苗队列，但预计将批准在期间使用更多疫苗 这个项目的资金来源。除了研究B细胞反应的不同方面， 在临床场景中，我们将搜索高度相似的“收敛”病毒特异性BCR等特征， 不同个体之间共享的可能具有预后价值的序列，例如通过揭示 个体对SARS-CoV-2具有有效的中和抗体应答。我们的目标如下： 具体目标1：分析急性COVID-19疾病中的B细胞反应。 具体目标2：评价B细胞对SARS-CoV-2记忆的形成。 具体目标3：分析粘膜B细胞和浆细胞对SARS-CoV-2的反应， 血液中的B细胞

PROJECT 2: SUMMARY The B cell and plasma cell populations that give rise to serum and mucosal antibodies will ultimately determine the effectiveness and duration of an individual’s humoral immune response to SARS-CoV-2 infection. We will use several mutually-supporting strategies to analyze these cells in the Boyd lab: single B cell phenotyping, B cell receptor (BCR) deep sequencing and determination of antigen specificity with DNA-barcoded antigen tetramers; bulk B cell immunoglobulin gene repertoire sequencing; and monoclonal antibody production from antigen-specific B cells. In complementary strategy, the Jardetzky lab will make use of yeast display libraries of patient-derived single-chain antibody variable fragments (ScFv) enriched for native heavy-light chain pairing to determine the antigen specificity of hundreds to thousands of antigen-specific clones per patient. In longitudinal peripheral blood samples and nasal biopsy samples we will thoroughly characterize antigen-specific B cell clones in patient responses to SARS-CoV-2. We hypothesize that with these data we will be able to determine which features of B cell clonal responses to SARS-CoV-2 are associated with differences in COVID-19 disease severity and differences between populations groups stratified by age, sex, ethnicity and pre-existing conditions, or dysregulated immunity in the context of checkpoint blockade treatment. We further hypothesize that analysis of memory B cell populations together with serological responses may predict which individuals will have longer-lasting humoral protection against reexposure to SARS-CoV-2. Finally, we will evaluate the B cell responses stimulated by natural infection compared to vaccination, beginning with the Covaxx peptide- based vaccine cohort, but with the expectation that additional vaccines will be approved for use during the period of this project funding. In addition to studying aspects of the B cell responses that differ among these clinical scenarios, we will search for features such as “convergent” virus-specific BCRs of highly similar sequences shared between different individuals that may have prognostic value, for example by revealing that an individual has a potent neutralizing antibody response to SARS-CoV-2. Our Aims are the following: Specific Aim 1: Analyze B cell responses in acute COVID-19 disease. Specific Aim 2: Evaluate the formation of B cell memory to SARS-CoV-2. Specific Aim 3: Analyze mucosal B cell and plasma cell responses to SARS-CoV-2 compared to responses of B cells in the blood.