Sequence-function relationship of influenza broadly neutralizing antibodies

项目总结 由于抗原性的漂移和变化，甲型流感病毒仍然是一个主要的全球卫生问题。快速 由点引起的人类流行性感冒亚型(H1N1和H3N2型)的抗原漂移 突变，会极大地阻碍疫苗的有效性，尽管季节性流感每年都会更新 疫苗。另一方面，抗原转移是由抗原之间的基因重新组合引起的 不同的毒株可能导致毁灭性的大流行，1918年的西班牙流感就是例证。人类感染 还报告了不同的人畜共患病亚型，如H5N1、H6N1、H7N9、H9N2和H10N8。AS 结果，一种通用的流感疫苗可以引起对不同流感的广泛保护性抗体反应 迫切需要菌株和亚型。广谱中和抗体(BNAbs)的发现 流感血凝素(HA)保守的茎区域增加了发展普遍的 流感疫苗。许多HA茎bNAb由免疫球蛋白重链胚系基因编码 IGHV6-1。由于这些IGHV6-1 HA干细胞bNAb可在多个个体中发现，并可与 组1具有(H1、H2、H5、H6、H8、H9、H11、H12、H13和H16)和组2具有(H3、H4、H7、H10、H14， 和H15)，它们代表了需要由通用流感诱导的抗体反应的类型 疫苗。这项拟议的研究将使用创新的高通量实验来定义序列特征 重链互补决定区3、轻链和体细胞超突变，使 IGHV6-1抗体是一种跨群HA干细胞bNAbs。潜在的分子机制将是 进一步以结构生物学方法为特征。这一结果将有助于准确估计生殖系 IGHV6-1 HA茎bNAbs的频率，并了解其亲和力成熟途径，进而 有利于通用流感疫苗的设计。此外，建立的实验框架 这项研究将适用于鉴定任何感兴趣的抗体。

PROJECT SUMMARY Influenza A virus continues to be a major global health concern due to antigenic drifts and shifts. Rapid antigenic drifts of circulating human influenza subtypes (H1N1 and H3N2), which are caused by point mutations, can drastically hamper vaccine effectiveness despite annual update of the seasonal influenza vaccine. On the other hand, antigenic shifts, which are caused by genetic reassortment between antigenically distinct strains, can result in devastating pandemic as exemplified by the 1918 Spanish flu. Human infections with different zoonotic subtypes, such as H5N1, H6N1, H7N9, H9N2, and H10N8 have also been reported. As a result, a universal influenza vaccine that can elicit broadly protective antibody responses to diverse influenza strains and subtypes is urgently needed. The discovery of broadly neutralizing antibodies (bnAbs) that target the conserved stem region of influenza hemagglutinin (HA) has raised the possibility of developing a universal influenza vaccine. A number of HA stem bnAbs are encoded by immunoglobulin heavy chain germline gene IGHV6-1. Since these IGHV6-1 HA stem bnAbs can be found in multiple individuals and can cross-react with both group 1 HAs (H1, H2, H5, H6, H8, H9, H11, H12, H13, and H16) and group 2 HAs (H3, H4, H7, H10, H14, and H15), they represent the type of antibody response that needs to be induced by a universal influenza vaccine. This proposed study will use innovative high-throughput experiments to define sequence features in the heavy-chain complementarity-determining region 3, light chain, and somatic hypermutations, that enable an IGHV6-1 antibody to be a cross-group HA stem bnAbs. The underlying molecular mechanisms will be further characterized by structural biology approach. The results will help accurately estimate the germline frequency of IGHV6-1 HA stem bnAbs and understand their affinity maturation pathway, which in turn will benefit the design of a universal influenza vaccine. Furthermore, the experimental framework established in this study will be applicable to characterize any antibody of interest.