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: 10220687
• 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 2023-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10220687
• 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; vaccine development; 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的结构复杂性，预防艾滋病疫苗的开发是一项艰巨的任务 信封（Env）蛋白质以及由免疫驱动的病毒式蛋白质之间的广泛抗原变异 逃生机制。此外，对env trimer上的非中和表位的免疫主持， 在病毒体表面上唯一的病毒抗原，从而使广泛中和抗体（BNAB）的诱导 疫苗接种特别困难。但是，孤立的BNAB的免疫学和结构特征 来自HIV-1感染的供体从引导了其他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）是一个有吸引力的BNAB 鉴于其线性和保守的表位序列的目标，如4E10，10E8和DH511和2F5所示 mabs。但是，包括肽，蛋白质支架或MPER/脂质体在内的MPER免疫原子疫苗具有 所有这些都无法引起中和活动，这表明病毒座上的第四纪结构的模仿不完整 表面。此外，MPER的可访问性受到限制，被GP160 Trimer Ectodobain屏蔽 从下方开始和病毒膜，导致MPER的免疫原性不良。 三聚体免疫原。事实证明 对于在GP120中针对表位的BNAB启发至关重要。同样，我们最近的MPER/脂质体结果 表明具有电流疫苗配方的B细胞受体提供的无限制接近角度是 有问题，导致大多数ABS诱导而没有中和活性或GP160三聚体反应性。 因此，MPER免疫原子必须模仿空间阻塞，并强制执行有限的AB可访问性 类似于gp160在病毒体上的第四纪结构构型所施加的方式类似 表面。给定MPER的N末端区域的序列变化，我们将制定策略 在AIM 1中针对MPER C末端区域的增强亚辅助AB反应。敲入（Ki）小鼠 模型生成具有长CDRH3环的抗体，外部因素，例如环状DI-GMP佐剂，ICOSL 持续的抗原供应将进行独立测试或结合起来的影响 MPer C末端特异性ABS。在AIM 2中，我们将利用作为平台的纳米轴技术 将GP160组装成类似于本地膜的环境，以促进或增强MPer特异性AB 具有理想的方法角度的响应并消除靶向矢量反应。结合 AIM 1中优化的疫苗方案，我们将采取互补的异源免疫策略 小鼠和兔模型，以促进4E10/10E8样bnabs的诱导。 DNA C粒子和 MPERTM/脂质体免疫原子将进一步不利于GP120-41的膨胀指向不良的占主导地位 AB反应是由GP160/纳米盘引起的，同时促进了足够的BNAB的血清滴度 具有必要的方法角度。将确定MPer特异性BNAB的遗传和生物物理特征。