Maximizing germinal centers and somatic hypermutation to HIV Env immunogens

摘要 我们认为生发中心的生物学特征对于将高亲和力的B细胞发展成非常重要的 困难的表位，如HIV env三聚体上的二级NAB表位，与特征良好的表位有很大的不同 常规抗原的GC生物学特征，如半抗原。我们已经证明了缓慢的交付 免疫接种改变了免疫反应的基本方面，这可能导致戏剧性的 NAB反应的改进(单元2019)。常规免疫策略很可能不足以满足 由于免疫障碍，针对艾滋病毒或其他困难病原体的bNab疫苗的开发， 包括B细胞免疫优势和GC的数量和质量。我们发现有两种独立的方法 RMS缓慢传递免疫导致更健壮的TFH细胞和更多与Env结合的GC B细胞， 通过纵向淋巴结(LN)细针抽吸物(FNA)追踪1.改善的GCs与 开发效价高20倍的自体第二层中和抗体(NAB)。BCR测序和抗体 常规推注定位免疫优势非中和(NNAB)表位 免疫动物，而缓慢递送免疫动物针对更多样化的一组表位，包括 多个二级NAB表位。我们将继续这些开创性的研究，使用新的缓释 探索与针对困难的HIV三聚体的亲和力成熟相关的生发中心生物学的技术 非人灵长类动物(NHP、恒河猴)的免疫原。

Abstract We propose that the features of germinal center biology important for developing high affinity B cells to a very difficult epitope, such as a tier 2 nAb epitope on HIV Env trimer, are very different than the well characterized features of GC biology for conventional antigens, such as haptens. We have demonstrated that slow delivery immunization changes fundamental aspects of the immune response, which can result in dramatic improvements in nAb responses (Cell 2019). Conventional immunization strategies will likely be insufficient for the development of a bnAb vaccine to HIV or other difficult pathogens due to the immunological hurdles posed, including B cell immunodominance and GC quantity and quality. We found that two independent methods of slow delivery immunization of RMs resulted in more robust Tfh cells and more GC B cells with Env-binding, tracked by longitudinal lymph node (LN) fine needle aspirates (FNA) 1. Improved GCs correlated with the development of > 20-fold higher titers of autologous tier 2 neutralizing Abs (nAbs). BCR sequencing and Ab mapping demonstrated targeting of immunodominant non-neutralizing (nnAb) epitopes by conventional bolus immunized animals, while slow delivery immunized animals targeted a more diverse set of epitopes, including multiple tier 2 nAb epitopes. We will continue these groundbreaking studies to use novel slow release technologies to probe the biology of germinal centers relevant to affinity maturation against a difficult HIV trimer immunogen in non-human primates (NHP, rhesus macaques).