Dynamics of the protective vaccine-induced human influenza neuraminidase B cell response

项目摘要 人类对流感的免疫应答主要是产生血凝素（HA）特异性抗体。 抗体（Abs）。流感HA蛋白的年突变率为1 - 2%，导致新病毒的发展。 对先前免疫力有抵抗力的菌株。病毒体表面上另一种最主要的糖蛋白是 神经氨酸酶（NA）。尽管具有免疫原性，但人NA特异性Ab的优势远低于HA， 可能是因为NA表达量仅为病毒体表面HA量的四分之一。年增长率 NA的突变约为HA的一半，而部分酶位点在A型（IAV）中保持保守 和B（IBV）流感病毒，使NA成为通用疫苗和治疗的潜在有效靶点 人单克隆抗体（hmAb）开发。靶向NA的抗体应答已证明具有保护性 以及在动物和人类中抗流感感染的治疗活性， 与有效保护、降低疾病严重程度和病毒脱落持续时间相关，独立于 比HA特异性Ab应答更强，证实NA是预防的有价值靶点， 治疗人类流感。尽管季节性人流感灭活疫苗（IIV）含有NA， 疫苗接种诱导的保护性人NA特异性体液应答的作用程度和机制 解决得不好。我们的研究表明，人类中的IIV确实诱导IAV和IBV NA- 特异性B细胞，并且它们编码的Ab克隆谱系包括具有广泛和有效能力的那些 预防和治疗流感感染。此外，我们已经证明，这些保护性NA特异性B细胞 克隆谱系存在于IIV后人类的长寿命骨髓浆细胞中， 来源于其持续存在的流通。我们证实NA介导的普遍体液保护作用，如 HA依赖于B细胞受体/Ab特异性，然而，在更大程度上HA也高度依赖于 对NA特异性Ab库的精确Fc/IgG亚类组成的影响。我们的核心假设是， 人IIV诱导具有广泛保护潜力的NA特异性B细胞应答，然而， 赋予普遍保护的适当特异性和抗病毒活性是亚显性的和零星诱导的， 因此其丰度不足以提供最佳保护。通过精确地定义那些 保护性人NA特异性B细胞克隆谱系，包括它们的诱导、频率、持续性、精确性、 特异性和作用机制，我们希望了解如何最佳地刺激它们， 人类通用疫苗策略。为此，我们建议：1）定义人NA特异性B细胞的进化 2）评估IV诱导的人NA B细胞谱系的能力， 抑制感染和传播和3）评估NA特异性hmAb保护的Fc依赖性。的 保护性人NA特异性B细胞克隆谱系的开发过程将被定义， 将其转化为鉴定的普遍的人类疫苗介导的流感感染保护。

PROJECT SUMMARY The human immune response against influenza is dominated by the production of hemagglutinin (HA)-specific antibodies (Abs). The yearly mutation rate in influenza HA proteins is 1-2% leading to development of new viral strains that are resistant to previous immunity. The other most predominant glycoprotein on the virion surface is neuraminidase (NA). Although immunogenic, predominance of human NA-specific Abs is much lower than HA, probably because NA expression is only one fourth the amount of HA on the virion surface. The yearly rate of mutation of NA is about half that of HA while part of the enzymatic site remains conserved across type A (IAV) and B (IBV) influenza viruses, making NA a potentially effective target for universal vaccine and therapeutic human monoclonal Ab (hmAb) development. Antibody responses targeting NA have demonstrated protective and therapeutic activity against influenza infection in animals, and in humans NA-inhibiting serum Abs have been correlated with effective protection, reduced disease severity, and duration of viral shedding, independent of or more strongly than HA-specific Ab responses, substantiating NA as a valuable target for the prevention and treatment of influenza in humans. Although seasonal human inactivated influenza vaccines (IIV) contain NA, the extent and mechanisms of action of protective human NA-specific humoral responses induced by vaccination are poorly resolved. Our research has demonstrated that IIV in humans does induce both IAV and IBV NA- specific B cells, and that the Ab clonal lineages they encode for include those that have broad and potent ability to protect and treat influenza infection. Further, we have demonstrated that these protective NA-specific B cell clonal lineages are present in long-lived bone marrow plasma cells in humans following IIV and are the likely source for their sustained presence in circulation. We posit that NA-mediated universal humoral protection, like HA, is dependent on B cell receptor/Ab specificity, however, to a greater extent than HA is also highly dependent on the precise Fc/IgG subclass composition of the NA-specific Ab repertoire. Our central hypothesis is that human IIV induces NA-specific B cell responses with broad protective potential, however, those with both the proper specificity and anti-viral activity to confer universal protection are subdominant and sporadically induced, hence at insufficient abundance to confer optimal protection. Through precisely defining the dynamics of those protective human NA-specific B cell clonal lineages, including their induction, frequency, persistence, precise specificity, and mechanisms of action, we expect to obtain insight on how to optimally stimulate them for future human universal vaccine strategies. To that end, we propose 1) define the evolution of human NA-specific B cell clonal lineages in response to seasonal IIV 2) assess the ability of IIV-induced human NA B cell lineages to inhibit infection and transmission and 3) evaluate the Fc-dependence of NA-specific hmAb protection. The process for the development of protective human NA-specific B cell clonal lineages will be defined and strategies to translate this to universal human vaccine-mediated protection from influenza infection identified.