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.

摘要 鉴于HIV-1病毒结构的复杂性，开发预防性艾滋病疫苗是一项艰巨的任务 免疫驱动的病毒准种间的包膜蛋白及广泛的抗原变异 逃生机制。此外，对环境三聚体上非中和表位的免疫优势 病毒粒子表面唯一的病毒抗原，通过诱导广谱中和抗体(BNab) 接种疫苗尤其困难。尽管如此，分离的bNAbs的免疫学和结构特征 来自HIV-1感染的捐赠者已经指导了更多的中和靶位以及新的方法 疫苗策略。Gp41亚基的膜近端外区(MPER)是一个很有吸引力的bNab 靶标给出其线性和保守的表位序列，如4E10、10E8和DH511和2F5 单抗。然而，MPER免疫原疫苗包括多肽、蛋白支架或MPER/脂质体 所有这些都未能引发中和活性，这表明病毒粒子上的第四级结构模仿不完整。 浮出水面。此外，mper的可及性是有限的，被gp160三聚体胞外结构域屏蔽，不受 引起的MPER免疫原性较差。 三聚体免疫原。一种封闭而不是开放的gp140三聚体免疫原构型已被证明是 对于针对gp120表位的bNAbs的激发很重要。同样，我们最近的MPER/脂质体结果 提示目前疫苗制剂提供给B细胞受体的不受限制的接近角度是 有问题的，导致诱导的大多数抗体没有中和活性或gp160三聚体反应。 因此，MPER免疫原必须模拟空间闭塞，并强制执行MPER有限的抗体可及性 以类似于gp160的四元结构构型强加于病毒粒子的方式 浮出水面。鉴于MPER N-末端区域的序列变异，我们将制定策略来 增强针对AIM中MPER C-末端区域的亚显性抗体反应1.敲入(KI)小鼠 具有CDRH3长环、环状双GMP佐剂、ICOSL等外在因素的抗体生成模型 和持久性抗原供应将单独或联合测试它们对增强 MPER C-终端区域特定的Abs。在目标2中，我们将利用作为平台的纳米盘技术 用于将gp160组装到天然的膜状环境中以启动或增强MPER特异性抗体 具有理想的接近角度的响应，并消除偏离目标的矢量响应。与 优化疫苗方案在目标1中，我们将在 小鼠和兔模型，促进4E10/10E8样bNAbs的诱导。DNA C粒子和 MPERTM/脂质体免疫原将进一步不利于gp120-41定向显性不良的扩展 由gp160/纳米盘诱导的AB反应，同时促进诱导足够的血清滴度的bNAbs 有必要的进场角度。将确定MPER特异性bNAbs的遗传和生物物理特征。