Sequence-function relationship of influenza broadly neutralizing antibodies

项目摘要 由于抗原漂移和转变，甲型流感病毒仍然是一个主要的全球健康问题。快速 流行的人流感亚型（H1N1和H3 N2）的抗原漂移，这是由点 尽管季节性流感每年都有更新， 疫苗另一方面，抗原性转变，这是由抗原性之间的遗传重配引起的， 不同的菌株，可以导致毁灭性的大流行，如1918年西班牙流感。人类感染 与不同的人畜共患病亚型，如H5 N1，H6 N1，H7N9，H9 N2和H10 N8也有报道。作为 因此，一种通用流感疫苗，可以引发对不同流感的广泛保护性抗体反应， 菌株和亚型。发现了靶向靶向的广泛中和抗体（bnAb）， 流感病毒血凝素（HA）的保守干细胞区提高了开发通用 流感疫苗。许多HA茎bnAb由免疫球蛋白重链种系基因编码， IGHV6-1。由于这些IGHV 6 -1 HA干bnAb可以在多个个体中发现，并且可以与IGHV 6 - 1 HA干bnAb交叉反应， 第1组HA（H1，H2，H5，H6，H8，H9，H11，H12，H13和H16）和第2组HA（H3，H4，H7，H10，H14， 和H15），它们代表了需要由通用流感病毒诱导的抗体应答类型 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， IGHV 6 -1抗体是交叉组HA茎bnAb。潜在的分子机制将是 进一步通过结构生物学方法表征。这些结果将有助于准确估计生殖系 IGHV 6 -1 HA干bnAb的频率，并了解其亲和力成熟途径，这反过来将 有利于设计通用流感疫苗。此外，建立的实验框架， 本研究将适用于表征任何感兴趣的抗体。

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.