Structure-function analysis of infection- and vaccine-induced B-cell repertoires

描述（由申请人提供）：抗原变异是目前疫苗开发面临的大量最关键问题的基础。流感病毒是解决这一问题的理想主题：它是我们可以有效接种的最易变的病原体，但其主要表面抗原变化如此之快，以至于几乎每年都必须引入新的疫苗。我们建议使用b细胞谱的创新分析和结构研究中的新可能性来了解交叉反应性和免疫优势的结构和免疫机制，作为设计免疫原的基础，这些免疫原将引起比目前使用的免疫原更广泛的中和反应。我们将测试以下三个假设，每个项目的三个目标与之对应。(1)灭活疫苗和感染诱导的b细胞库在多克隆活化程度和中和广度上存在差异；佐剂和非佐剂TIV免疫引起的反应谱不同，因为佐剂增加了识别表位的宽度。(2)广泛反应性抗体，包括识别异亚型茎表位的抗体，在真正一次免疫后比二次免疫后较少出现，这是由于多次HA刺激扩大了反应。(3)有效诱导抗体对抗所需表位需要：(a)有利的种系抗体增殖和(b)达到所需最终特异性的亲和成熟途径；针对特定表位的抗体有首选的种系前体和成熟途径。参与本提案的研究小组汇集了免疫学、病毒学、结构生物学和疫苗开发方面的优势。在过去的合作中，主要研究人员密切而有效地合作。

DESCRIPTION (provided by applicant): Antigenic variation underlies a large number of the most critical problems now facing vaccine development. Influenza virus is an ideal subject for tackling this issue: it is the most variable pathogen against which we can effectively vaccinate, but its principal surface antigen varies so rapidly that new vaccines must be introduced almost yearly. We propose to use innovative analyses of B-cell repertoires and new possibilities in structural studies to understand the structural and immunological mechanisms underlying cross reactivity and immunodominance, as a foundation for designing immunogens that will elicit a more broadly neutralizing response than those currently in use. We will test the following three hypotheses, to which the three Aims of each Project correspond. (1) The B-cell repertoires elicited by inactivated vaccines and by infection differ in degree of polyclonal activation and breadth of neutralization; the repertoires elicited by immunization with adjuvanted and non-adjuvanted TIV differ because adjuvant increases the breadth of recognized epitopes. (2) Broadly reactive Abs, including those recognizing the heterosubtypic stem epitope, are less frequent after true primary than after secondary TIV immunization due to broadening of the response by multiple HA stimulations. (3) Efficient induction of Abs against a desired epitope requires: (a) proliferation of a favorable germline Ab and (b) an affinity maturation pathway to a desired final specificity; there are preferred germline precursors and maturation pathways for Abs targeting particular epitopes. The group of investigators that joins in this proposal brings together strengths in immunology, virology, structural biology, and vaccine development. The principal investigators have worked closely and effectively together in past collaborations.