Immunogen Design for Induction of HIV distal gp41 broadly neutralizing antibodies

总体目标是开发能够启动和选择 HIV-1 广泛中和抗体的免疫原 (bnAb) 谱系针对 HIV Env gp41 的远端膜近端外部区域 (MPER)。远端 gp41 MPER 抗体类型（例如 10E8 和 DH511）是理想的选择，因为它们是最广泛的抗体类型之一 和分离出的强效 bnAb。 bnAb 免疫原设计谱系有两种策略。 (1) bnAb的定义 克隆谱系谱系，推断bnAb未突变共同祖先（UCA）并选择自体 结合的环境称为 B 细胞谱系免疫原设计。 (2) 基于结构的设计，使用结构 顺序谱系 Abs 用于设计与 bnAb 谱系成员结合的环境。这里我们建议结合 设计可以启动和诱导远端 MPER 的免疫原的两种策略的优点 bnAb。我们将使用新分离的 DH511 谱系 UCA、中间抗体 (IAs) 和 bnAbs 作为 设计连续免疫原的试剂将选择 DH511 样前体并导致 bnab 开发（项目 1，William Schief，PI），并在生理相关性中测试这些免疫原 bnAb 开发的敲入小鼠模型（项目 2（Munir Alam，PI，小动物模型核心， Ming Tian，PI，Fred Alt，Co-I）。计算程序，用于检测的抗原受体突变分析仪 低可能性发生率 (ARMADiLLO)（项目 2），允许定义关键抗体 诱导的体细胞突变将用于确定成功疫苗所需的关键 IAs 目标。 总体具体目标 1. 定义成功疫苗将实现的关键 IAs 和抗体体细胞突变 需要选择导致远端 MPER bnAb 诱导。 （项目1和2） 总体具体目标 2. 设计种系靶向 (GT) 初免和加强免疫原 DH511 前体与关键 IAs 和成熟 DH511 bnAb 具有最佳亲和力，并且可以选择 正确/所需的 IAs 和 bnAb。 （项目1） 总体具体目标 3. 解析 DH511 和 DH511 类谱系的共晶和冷冻电镜结构 具有 Env 免疫原的抗体可沿着 bnAb 成熟途径移动谱系，并使 设计额外的免疫原以完成远端 MPER bnAbs B 细胞谱系的诱导。 （项目1） 总体具体目标 4. 从 DH511 UCA 和 IA 免疫中选择最佳 Env 免疫原 VH 和 VL 敲入小鼠。这将通过使用新颖的 DH511 UCA VHDJH 重排来完成 哈佛大学的 Ming Tian 和 Fred Alt 最近开发了鼠标。 （小动物核心；项目 1 和 2）。 三个领先学术团队在艾滋病毒疫苗免疫原设计方面的合作将带来 结合基于结构和基于谱系的设计方面的专业知识，将成为实现 疫苗诱导不利抗体谱系（特别是远端 MPER bnAb）的问题。

The overall objective is to develop immunogens that will initiate and select HIV-1 broad neutralizing antibody (bnAb) lineages directed to the distal membrane proximal external region (MPER) of HIV Env gp41. Distal gp41 MPER antibody types such as 10E8 and DH511 are desirable because they are among the most broad and potent bnAbs isolated. There are two strategies for bnAb immunogen design lineages. (1) Define bnAb clonal lineage genealogies, infer the bnAb unmutated common ancestor (UCA) and select autologous Envs that bind—termed B cell lineage immunogen design. (2) Structural-based design, using structures of sequential lineage Abs to design Envs that bind to bnAb lineage members. Here we propose to combine the strengths of both strategies to design immunogens that can initiate and induce distal MPER bnAbs. We will use the newly isolated DH511 lineage UCA, intermediate antibodies (IAs) and bnAbs as reagents upon which to design sequential immunogens that will select DH511-like precursors and lead to bnab development (Project 1, William Schief, PI), and to test these immunogens in physiologically relevant knock-in mouse model of bnAb development (Project 2 (Munir Alam, PI, Small Animal Models Core, Ming Tian, PI, Fred Alt, Co-I). A computational program, Antigen Receptor Mutation Analyzer for Detection of Low Likelihood Occurrences (ARMADiLLO) (Project 2) that allows for definition of the critical antibody somatic mutations to be induced will be used to determine key IAs that a successful vaccine will need to target. Overall Specific Aim 1. Define the key IAs and antibody somatic mutations that a successful vaccine will need to select to lead to distal MPER bnAb induction. (Projects 1 and 2) Overall Specific Aim 2. Design of germline targeting (GT) prime and boost immunogens that bind to the DH511 precursors and to key IAs and mature DH511 bnAbs in optimal affinities and can select the correct/desired IAs and bnAbs. (Project 1) Overall Specific Aim 3. Solve co-crystal and cryoEM structures of DH511 and DH511-like lineage antibodies with Env immunogens that move the lineage along the bnAb maturation pathway and enable design of additional immunogens to complete the induction of distal MPER bnAbs B cell lineages. (Project 1) Overall Specific Aim 4. Selection of optimal Env immunogens from immunizations of DH511 UCA and IA VH and VL knock-in mice. This will be accomplished by use of the novel DH511 UCA VHDJH-rearranging mouse recently developed by Ming Tian and Fred Alt at Harvard. (Small Animal Core; Projects 1 and 2). This collaboration of three leading academic teams in HIV vaccine immunogen design will bring together expertise in structure-based and lineage-based design, and will be a powerful approach to the problem of vaccine induction of disfavored antibody lineages in general and distal MPER bnAbs in particular.