Triggering germline-encoded broadly neutralizing antibody responses against influenza virus

项目摘要/摘要 这是拉贡研究所的丹尼尔·林伍德博士和法昆多·巴蒂斯塔博士的申请 麻省理工学院和哈佛大学。两位研究人员都定义了B细胞抗原识别原理来告知抗体 疫苗设计，并为此，开发了两个正交转基因小鼠模型，概括了人类 体内的抗体反应。研究人员建议将这些模型应用于评估生殖系刺激。 已知可产生抗甲型流感广谱中和抗体(BNAbs)的人类B细胞系 病毒(IAV)，这是流感住院和大流行威胁的主要原因。大多数抗体 对IAV的反应主要是非靶标、非中和活动，然而，来自调查人员的工作 表明由抗体VH基因IGHV1-69组装的人BCR具有天然的特异性。 I型IAV血凝素刺突蛋白的保守脆弱部位--茎-bNab表位 (IAV亚型：H1、H2、H5、H6、H8、H9、H11、H12、H12、H16)。以测试这是否具有疫苗的遗传特性- 可扩增的bNab发育途径，研究人员设计了Lingwood小鼠系统， 抗体随着人类抗体VH基因(例如IGHV1-69)和完全人类CDRH3多样性而产生。 该系统的基因操作使体内B细胞滴定能够与IGHV1-69 B细胞频率匹配 在人类身上发现。依次用SS-NP免疫这些小鼠，SS-NP是一种展示bNab靶标的纳米颗粒， 已经成功地对IGVH1-69bNab前体进行了胚系刺激，并成功地依赖IGHV1-69扩增了 BNab反应；第一个通过接种疫苗诱导高滴度IAV bNAb的例子。这一回应也 提供广泛的保护，预防第1组禽流感，包括大流行禽流感，支持调查人员的 核心假设是，胚系抗体靶向疫苗可以诱导出广泛保护性的bNAbs。在……里面 目标1，调查人员将确定SS-NP是否为IGHV1-69编码的通用助推器 B细胞记忆对模拟人类免疫的不同IAV“群”的bNab反应 流感病史。在目标2中，研究人员将定义如何重新聚焦血清抗体以对抗这种特定的 BNab靶标还增强了抗体Fc效应器的功能，可能通过激活共同实现保护 先天免疫力。在目标3中，巴蒂斯塔小鼠系统将用于评估疫苗的扩展 IGHV1-69 bNAbs与人IGHV1-18和IGHV6-1类bNab谱系一起，中和 其余第2组IAV亚型(H3、H4、H7、H10、H14、H15)。在该系统中，小鼠IgM B细胞携带 每条途径的单个人bNab前体被共同转移到单个受体小鼠。跟随 免疫，通过B细胞生发中心的进展来单独跟踪谱系扩张 然后进入免疫记忆。将用SS-NP、SS-np2和SS-np3联合免疫这些动物； 几何形状相同的纳米颗粒对每个bNab前体具有不同的亲和力。选择性集体 扩大这些bNab谱系的目的是克服传统流感疫苗方法的失败。

Project Summary / Abstract This is an application by Dr. Daniel Lingwood and Dr. Facundo Batista, faculty members of the Ragon Institute of MGH, MIT and Harvard. Both investigators define B cell-antigen recognition principles to inform antibody vaccine design, and for this, have developed two orthogonal transgenic mouse models that recapitulate human antibody responses in vivo. The investigators propose to apply these models to evaluate germline stimulation of human B cell lineages known to give rise to broadly neutralizing antibody (bnAbs) against influenza A viruses (IAV), which account for the majority of flu-hospitalizations and pandemic threats. Most antibody responses to IAV are dominated by off-target, non-neutralizing activities, however, work from the investigators indicates that human BCRs assembled from the antibody VH gene, IGHV1-69, possess natural specificity for a conserved site of vulnerability, the stem-bnAb epitope on the hemagglutinin spike proteins from Group 1 IAV (IAV subtypes: H1, H2, H5, H6, H8, H9, H11, H12, H12, H16). To test if this genetically endows for vaccine- amplifiable bnAb development pathways, the investigators have engineered the LINGWOOD mouse system, where antibodies develop with human antibody VH genes (e.g. IGHV1-69) and full human CDRH3 diversity. Genetic manipulation of this system enables in vivo B cell titration to match the IGHV1-69 B cell frequency found in humans. Sequentially immunizing these mice with SS-np, a nanoparticle displaying the bnAb target, has succeeded in germline stimulation of IGVH1-69 bnAb precursors and IGHV1-69-dependent expansion of bnAb responses; the first example of eliciting high titer IAV bnAbs through vaccination. This response also provided broad protection against Group 1 IAV, including pandemic bird flu, supporting the investigators' central hypothesis that broadly protective bnAbs can be elicited by germline antibody-targeting vaccines. In Aim 1, the investigators will define whether SS-np stands as a universal booster of the IGHV1-69-encoded bnAb response after introduction of B cell memory to diverse IAV `swarms' that simulate human immune history to influenza. In Aim 2, the investigators will define how refocusing serum antibodies against this specific bnAb target also enhances antibody Fc effector functions, potentially co-enabling protection through activation of innate immunity. In Aim 3, the BATISTA mouse system will be used to evaluate vaccine-expansion of IGHV1-69 bnAbs alongside the human IGHV1-18- and IGHV6-1-class bnAb lineages, which neutralize the remaining Group 2 IAV subtypes (H3, H4, H7, H10, H14, H15). In this system, murine IgM B cells bearing individual human bnAb precursors of each pathway are co-transferred to a single recipient mouse. Following immunization, lineage expansions are individually tracked via their progression through B cell germinal centers and then into immune memory. The animals will be co-immunized with SS-np, SS-np2, and SS-np3; three geometrically identical nanoparticles bearing distinct affinities for each bnAb precursor. Selective + collective expansion of these bnAb lineages aims to overcome failure of traditional influenza vaccine approaches.