Clonal Dynamics of the antibody response

项目摘要 产生适当的抗体反应对于防止再感染和有效地预防再感染至关重要。 接种疫苗，特别是在病毒性疾病的情况下。除了经过充分研究的定量参数外， 例如抗体滴度和亲和力，其它的，更多的与克隆组成相关的定性参数， 应答也在抗体介导的保护中起关键作用。这些包括抗原和表位特异性， 这是病毒中和能力和抗体宽度以及整体克隆多样性的关键， 影响免疫优势的程度，从而影响病毒通过突变逃避免疫的能力。 尽管它们的重要性，GC生物学的这些“生态”方面仍然知之甚少， 在机械层面上被忽视了。 我们的长期目标是对B的竞争力的消长有一个机械的理解 在免疫反应的各个阶段的细胞克隆形成了最终的组成，特异性， 血清抗体的保护效力。在我们之前的研究中，使用基于“Brainbow”的B细胞命运- 映射模型，我们专注于反应的生发中心（GC）和记忆阶段，揭示了如何 高度多样化的早期应答者向寡克隆性汇集，首先通过GC选择（包括 在慢性肠道相关GC中），然后通过二次加强显著增加。我们现在建议将我们的工作 使用这些相同的工具来研究长寿病毒诱导的GC中延长选择的克隆动力学 (Aim 1）和浆母细胞和浆细胞从GC前体的进行性分化（目的2）。我们 我还提出了一个新的“分子命运映射”系统，以确定克隆动态如何影响最终的 血清抗体组成（目的3）。这使我们能够研究血清水平现象的B细胞生物学 例如抗原印记/原始抗原印记、免疫显性和病毒逃逸。 我们希望我们的研究结果将提供更多的机械理解如何组成和保护 血清抗体的有效性是由B细胞克隆竞争的动力学决定的，其含义是： 设计针对流感、艾滋病毒和SARS-CoV-2的有效疫苗接种策略。

PROJECT SUMMARY Generating an appropriate antibody response is critical for protection against reinfection and for the effectiveness of vaccination, particularly in the context of viral diseases. In addition to well-studied quantitative parameters such as antibody titer and affinity, other, more qualitative parameters related to the clonal composition of the response also play critical roles in antibody-mediated protection. These include antigen and epitope specificity, which is key to viral neutralization capacity and antibody breadth, and overall clonal diversity, which strongly influences the degree of immunodominance and therefore the ability of viruses to escape immunity by mutation. Despite their importance, such “ecological” aspects of GC biology remain poorly understood and systematically understudied at the mechanistic level. Our long-term goal is to develop a mechanistic understanding of how the competitive waxing and waning of B cell clones at the various stages of the immune response shapes the ultimate composition, specificity, and protective efficacy of serum antibody. In our previous studies, using multicolor “Brainbow”-based B cell fate- mapping models, we focused on the germinal center (GC) and memory phases of the response, revealing how highly diverse early responders are funneled towards oligoclonality, first progressively by GC selection (including in chronic gut-associated GC) and then dramatically by secondary boosting. We now propose to extend our work using these same tools to investigate the clonal dynamics of prolonged selection in long-lived virus-induced GCs (Aim 1) and of the progressive differentiation of plasmablasts and plasma cells from GC precursors (Aim 2). We also propose a new “molecular fate-mapping” system to determine how clonal dynamics impact the ultimate composition of serum antibody (Aim 3). This allows us to investigate the B cell biology of serum-level phenomena such as antigenic imprinting/original antigenic sin, immunodominance, and viral escape. We expect our findings will provide greater mechanistic understanding of how the composition and protective effectiveness of serum antibody is determined by the dynamics of B cell clonal competition, with implications for the design of effective vaccination strategies for influenza, HIV, and SARS-CoV-2.