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

项目总结 人类对流感的免疫反应主要是血凝素(HA)特异性的产生 抗体(Abs)。流感血凝素蛋白每年的变异率为1-2%，导致新病毒的产生 对先前的免疫有抵抗力的菌株。病毒粒子表面的另一种最主要的糖蛋白是 神经氨酸酶(NA)。虽然人NA特异性抗体具有免疫原性，但其优势远低于HA， 可能是因为NA的表达只有病毒粒子表面HA的四分之一。年增长率 NA的突变大约是HA的一半，而A型(IAV)的部分酶切位点保持保守 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 人单抗(HmAb)研制。针对NA的抗体反应已显示出保护作用 以及在动物和人类中对流感感染的治疗活性-抑制NA的血清抗体已经被 与有效保护、降低疾病严重性和病毒脱落持续时间相关，独立于或 比HA特异性抗体反应更强，证实NA是预防和治疗的有价值的靶点 人类流感的治疗。尽管季节性人类流感灭活疫苗(IIV)含有甲型流感病毒，但 疫苗免疫诱导的保护性人类NA特异性体液反应的作用范围和机制 没有得到很好的解决。我们的研究表明，IIV在人类体内确实会诱发IAV和IBV NA- 它们编码的抗体克隆谱系包括那些具有广泛和强大能力的 预防和治疗流感感染。此外，我们已经证明了这些保护性的NA特异性B细胞 在IVIV后，人类长寿的骨髓浆细胞中存在克隆性谱系，可能是 这是它们在流通中持续存在的来源。我们假设NA介导的普遍体液保护，如 HA依赖于B细胞受体/抗体的特异性，但在更大程度上也比HA具有高度的依赖性 关于NA特异性抗体谱系Fc/Ig G亚类的精确组成。我们的中心假设是 人类免疫缺陷病毒诱导具有广泛保护潜力的NA特异性B细胞反应，然而，那些既有 赋予普遍保护的适当特异性和抗病毒活性是次要的和零星诱导的， 因此，其丰度不足以提供最佳保护。通过精确地定义那些 保护性人类NA特异性B细胞克隆谱系，包括其诱导、频率、持续时间、精确度 特殊性和作用机制，我们希望获得关于如何为未来最佳地刺激它们的见解 人类通用疫苗策略。为此，我们建议1)定义人类NA特异性B细胞的进化 对季节性IIV反应的克隆系评估IIV诱导的人NA B细胞系的能力 抑制感染和传播；3)评估NA特异性hmAb保护的Fc依赖性。这个 将确定保护性人类NA特异性B细胞克隆谱系的发展过程和战略 将其转化为普遍的人类疫苗介导的预防流感感染已确定的保护措施。

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.