Clonal Dynamics of the antibody response

项目总结 产生适当的抗体反应对于预防再感染和有效治疗至关重要。 疫苗接种的重要性，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之外 例如抗体效价和亲和力，以及与克隆组成有关的其他更定性的参数 应答在抗体介导的保护中也起着关键作用。这些包括抗原和表位特异性， 这是病毒中和能力和抗体广度以及总体克隆多样性的关键，这一点非常重要 影响免疫优势程度，从而影响病毒通过变异逃避免疫的能力。 尽管它们很重要，但GC生物学的这些“生态”方面仍然知之甚少，也很不系统 在机械学层面上未完成学业。 我们的长期目标是发展一种机械性的理解，即B的竞争兴衰是如何 在免疫反应的不同阶段的细胞克隆形成了最终的成分、特异性和 血清抗体的保护作用。在我们之前的研究中，使用基于多色“脑弓”的B细胞命运- 映射模型，我们专注于生发中心(GC)和记忆阶段的反应，揭示了如何 高度多样化的早期应答者向寡克隆方向发展，首先通过GC选择(包括 在慢性胃肠道相关性GC中)，然后显著地通过二次增强。我们现在提议延长我们的工作 用同样的工具研究长寿命病毒诱导的GC中延长选择的克隆动力学 (目标1)以及从GC前体向浆母细胞和浆细胞的逐渐分化(目标2)。我们 我还提出了一个新的分子命运图谱系统来确定克隆动力学如何影响终极 血清抗体组成(目标3)。这使得我们能够研究血清水平现象的B细胞生物学现象 如抗原印迹/原始抗原SIN、免疫优势和病毒逃逸。 我们希望我们的发现将提供更好的机制理解如何组成和保护 血清抗体的有效性是由B细胞克隆竞争的动态决定的，这意味着 设计有效的流感、艾滋病毒和SARS-CoV-2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.