Approaches to inducing broadly neutralizing antibodies with immunogens mimicking steric occlusion of the MPER as configured on the HIV-1virion surface

使用模拟 HIV-1 病毒粒子表面配置的 MPER 空间封闭的免疫原诱导广泛中和抗体的方法

• 批准号: 10452514
• 负责人: Mikyung Kim
• 金额: $ 44.5万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-08-01 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10452514
• 关键词: AIDS Vaccines; Acquired Immunodeficiency Syndrome; Adjuvant; Adopted; Affinity; Antibodies; Antibody Affinity; Antibody Formation; Antibody Response; Antibody-Producing Cells; Antigenic Variation; Antigens; B-Cell Antigen Receptor; B-Lymphocytes; Binding; Biophysics; C-terminal; Cells; Characteristics; DNA; Development; Environment; Epitopes; Exhibits; Fostering; Generations; Genetic; HIV; HIV Envelope Protein gp120; HIV-1; Human; IGH@ gene cluster; Immune; Immune Tolerance; Immunization; Immunologics; Infection; Knock-in; Knock-in Mouse; Length; Link; Liposomes; Locales; Membrane; Membrane Proteins; Modeling; Monoclonal Antibodies; Mus; N-terminal; Oryctolagus cuniculus; Peptides; Periodicity; Preventive; Production; Recombinant Antibody; Regimen; Scaffolding Protein; Serum; Specificity; Structure; Structure of germinal center of lymph node; Surface; Testing; Time; Vaccination; Vaccines; Variant; Viral; Viral Antigens; Viral Vector; Virion; design; efficacy evaluation; env Gene Products; fight against; gp160; humanized mouse; immunogenicity; improved; mimicry; mouse model; nanodisc technology; nanodisk; neutralizing antibody; novel strategies; particle; response; vaccination strategy; vaccine development; vaccine formulation; vaccine strategy; vector; vector vaccine

ABSTRACT Development of a preventive AIDS vaccine is a daunting task given the structural complexity of the HIV-1 envelope (Env) protein as well as extensive antigenic variation among viral quasispecies driven by immune escape mechanisms. Moreover, immunodominance toward non-neutralizing epitopes on the Env trimer, the sole viral antigen on the virion surface, makes the elicitation of broadly neutralizing antibody (bnAb) by vaccination particularly difficult. Nonetheless, immunological and structural characterizations of isolated bnAbs from HIV-1 infected donors have guided additional neutralizing target epitopes along with new approaches in vaccine strategies. The membrane proximal external region (MPER) of gp41 subunit is an attractive bnAb target given its linear and conserved epitope sequences as exemplified by 4E10, 10E8 and DH511 and 2F5 mAbs. However, MPER immunogen vaccines including peptides, protein scaffolds or MPER/liposomes have all failed to elicit neutralizing activities, suggesting incomplete mimicry of the quaternary structure on the virion surface. Furthermore, the accessibility of the MPER is limited, being shielded by gp160 trimer ectodomain from above and the viral membrane from below, contributing to the poor immunogenicity of the MPER elicited by trimer immunogens. A closed rather than open configuration of gp140 trimer immunogens has proven to be important for elicitation of bnAbs directed to epitopes in gp120. Likewise, our recent MPER/liposome results suggest that the unrestricted approach angle afforded to the B cell receptor with current vaccine formulation is problematic, resulting in induction of a majority of Abs without neutralizing activity or gp160 trimer reactivity. Therefore, MPER immunogens must mimic spatial occlusion and enforce limited Ab accessibility to the MPER in a manner analogous to that imposed by the quaternary structural configuration of gp160 on the virion surface. Given sequence variations in the N-terminal region of the MPER, we will develop strategies to augment subdominant Ab responses directed to the MPER C-terminal region in Aim 1. A knock-in (KI) mouse model generating antibodies with long CDRH3 loops, extrinsic factors such as cyclic di-GMP adjuvant, ICOSL and persistent antigen supply will be tested independently or in combination for their impact on augmenting MPER C-terminal region-specific Abs. In Aim 2, we shall exploit nanodisc technology that serves as a platform for the assembly of gp160 into a native membrane-like environment to prime or boost MPER-specific Ab responses with a desirable approach angle and to eliminate off-target vector responses. In conjunction with optimized vaccine regimen in Aim 1, we shall pursue complementary heterologous immunization strategies in mouse and rabbit models to foster the induction of 4E10/10E8-like bnAbs. DNA C-particle and MPERTM/liposome immunogens will further disfavor expansion of gp120-41 directed dominant undesirable Ab responses elicited by the gp160/nanodisc, while facilitating the induction of sufficient serum titers of bnAbs with requisite approach angles. Genetic and biophysical features of MPER-specific bnAbs will be determined.

抽象的 鉴于 HIV-1 结构的复杂性，开发预防性艾滋病疫苗是一项艰巨的任务 包膜（Env）蛋白以及免疫驱动的病毒准种之间广泛的抗原变异 逃逸机制。此外，针对 Env 三聚体上的非中和表位的免疫显性， 病毒颗粒表面唯一的病毒抗原，通过以下方式引发广泛中和抗体（bnAb） 疫苗接种特别困难。尽管如此，分离的 bnAb 的免疫学和结构特征 来自 HIV-1 感染捐献者的捐赠者指导了额外的中和目标表位以及新方法 疫苗策略。 gp41 亚基的膜近端外部区域 (MPER) 是一种有吸引力的 bnAb 给定其线性和保守表位序列的目标，如 4E10、10E8 和 DH511 和 2F5 所示 单克隆抗体。然而，包括肽、蛋白质支架或MPER/脂质体在内的MPER免疫原疫苗已 所有这些都未能引发中和活性，表明对病毒体四级结构的模仿不完全 表面。此外，MPER 的可及性受到限制，受到 gp160 三聚体胞外域的屏蔽 上面的病毒膜和下面的病毒膜，导致 MPER 的免疫原性较差 三聚体免疫原。已证明 gp140 三聚体免疫原的封闭构型而非开放构型 对于诱导针对 gp120 中表位的 bnAb 非常重要。同样，我们最近的 MPER/脂质体结果 表明当前疫苗配方为 B 细胞受体提供的不受限制的接近角度是 有问题，导致诱导大多数抗体而没有中和活性或 gp160 三聚体反应性。 因此，MPER 免疫原必须模拟空间闭塞并强制限制抗体对 MPER 的可及性 以类似于 gp160 四级结构构型对病毒颗粒施加的方式 表面。鉴于 MPER N 端区域的序列变异，我们将制定策略 增强针对目标 1 中 MPER C 末端区域的次优势抗体反应。敲入 (KI) 小鼠 模型生成具有长 CDRH3 环的抗体、环二 GMP 佐剂、ICOSL 等外在因素 和持久的抗原供应将被独立或组合测试其对增强的影响 MPER C 末端区域特异性抗体。在目标 2 中，我们将利用纳米圆盘技术作为平台 用于将 gp160 组装到天然膜样环境中，以启动或增强 MPER 特异性抗体 以理想的接近角进行响应并消除偏离目标的矢量响应。结合 目标1中优化疫苗方案，我们将在以下方面寻求互补的异源免疫策略： 小鼠和兔子模型促进 4E10/10E8 样 bnAb 的诱导。 DNA C 粒子和 MPERTM/脂质体免疫原将进一步不利于 gp120-41 定向显性的不良扩增 gp160/nanodisc 引发抗体反应，同时促进足够的 bnAb 血清滴度的诱导 具有必要的接近角。 MPER 特异性 bnAb 的遗传和生物物理特征将被确定。