Immunogenicity of the newly identified V3 crown vulnerable site

新发现的 V3 冠脆弱位点的免疫原性

基本信息

批准号：
10548294
负责人：
XIANGPENG KONG
金额：
$ 27.06万
依托单位：
NEW YORK UNIVERSITY SCHOOL OF MEDICINE
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-07-05 至 2024-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10548294
关键词：
Animals Antibodies Antibody Response Antigens Area B-Lymphocytes Binding Biological Assay Blood specimen Categories Characteristics Cryoelectron Microscopy Dental crowns Enzyme-Linked Immunosorbent Assay Epitope Mapping Epitopes Foundations Future Genes Glycoproteins Goals HIV HIV Envelope Protein gp120 HIV vaccine HIV-1 Human Immunization Immunoglobulin A Immunoglobulin Class Switching Immunoglobulin G Location Maps Membrane Proteins Modeling Modification Molecular Target Monoclonal Antibodies Mus N-terminal Negative Staining Oryctolagus cuniculus Outcome Patients Polysaccharides Regimen Site Structure Surface Testing V3 Loop Vaccines Virus beta pleated sheet design disulfide bond immunogenic immunogenicity neutralizing antibody nonhuman primate novel pathogen purge rational design response scaffold screening vaccination strategy virus envelope

项目摘要

To be able to induce antibody (Ab) responses against the HIV-1 envelope (Env) spike vulnerable sites defined by broadly neutralizing antibodies (bnAbs) will likely lead to a protective vaccine. Many HIV bnAbs have been discovered and their epitopes have been carefully mapped on the surface of Env, and these epitopes have been categorized into a number of well characterized classes. However, a consistently induction of bnAb responses targeting any of those currently well characterized vulnerable sites is still extremely difficult because of the unusual features of these bnAbs and their associated vulnerable sites, such as the requirement of a long CDR H3 to penetrate the glycan shield of the Env spike. Thus, identification of additional vulnerable sites with more favorable characteristics for rational targeting may help to increase our capability of induction of bnAb responses. We have identified recently a new vulnerable site by mapping the epitope of bnAb M4008_N1 and characterizing its antibody-antigen interaction. M4008_N1 is a bnAb that can neutralize about 40% of the primary isolates tested and its lineage class-switched to both IgG and IgA. We showed that by cryo-EM the epitope of M4008_N1 is centered at the crown region of the third variable loop (V3) of gp120 in the prefusion Env trimer. The unique characteristics of the M4008_N1 epitope and its mode of interaction with the V3 crown suggest a strategy to induce M4008_N1-like Ab responses by a V3 priming and heterologous boosting with stabilized Env trimer. As we have demonstrated previously, the V3 crown Ab responses are relatively straightforward to elicit by V3 immunogens. We therefore hypothesize that, since the V3 crown -hairpin is a common structure and M4008_N1 can bind V3 loop itself, antibodies that engage the N-terminal strand by a β- sheet interaction, like that of M4008_N1, can be induced by V3 immunogens, and such M4008_N1-like antibody responses can then be boosted with a subsequent immunization with a V3-stabilized Env trimer, which harbors the whole epitope of bnAb M4008_N1. Early versions of the SOSIP immunogens were known to induce non-neutralizing V3 antibodies, but some V3-stabilized versions seemed to be able to purge non- neutralizing V3 antibody responses. These V3-stabilized SOSIP trimers can therefore be used for the heterologous boost to induce M4008_N1-like antibody responses. We will test our hypothesis in a rabbit model using a set of carefully selected to be optimal in the heterologous prime/boost strategy, and we have two Aims. (1) Selection of the best immunogen combination, (2): Rabbit immunization and characterization of the antibody responses. The expected outcome of this project is a proof of principle demonstration for the immunogenicity targeting the newly identified V3 crown vulnerable site and to lay a foundation for future extensive immunogenicity studies including potentially non-human primate studies.

能够诱导针对 HIV-1 尖峰 (Env) 脆弱定义位点的抗体 (Ab) 包膜反应通过广泛中和抗体 (bnAb) 可能会产生保护性疫苗许多 HIV bnAb 已被开发出来。发现了它们的表位，并已在 Env 表面仔细绘制了图谱，并且这些表位已然而，bnAb 的诱导始终如一。针对目前已明确描述的脆弱站点的响应仍然极其困难，因为这些 bnAb 的不寻常特征及其相关的脆弱位点，例如需要长 CDR H3 穿透 Env 刺突的聚糖屏蔽，从而识别其他易受攻击的位点。更有利的特征有利于合理靶向可能有助于提高 bnAb 的诱导能力我们最近通过绘制 bnAb M4008_N1 和的表位确定了一个新的易受攻击的位点。 M4008_N1 是一种 bnAb，可以中和约 40% 的抗体。测试的原代分离株及其谱系类别转换为 IgG 和 IgA，我们通过冷冻电镜证明了这一点。 M4008_N1 的表位集中在预融合中 gp120 的第三个可变环 (V3) 的顶部区域 Env三聚体。M4008_N1表位的独特特征及其与V3冠的相互作用模式。建议通过 V3 引发和异源加强来诱导 M4008_N1 样抗体反应的策略正如我们之前所证明的，V3 冠抗体反应相对稳定。因此，我们捕获了这一点，因为 V3 冠 -发夹是一个共同结构和 M4008_N1 可以结合 V3 环本身，抗体通过 β- 接合 N 端链像 M4008_N1 一样，片层相互作用可以由 V3 免疫原诱导，并且这种 M4008_N1 样然后可以通过使用 V3 稳定的 Env 三聚体进行后续免疫来增强抗体反应，已知早期版本的 SOSIP 免疫原包含 bnAb M4008_N1 的整个表位。诱导非中和性 V3 抗体，但一些 V3 稳定版本似乎能够清除非中和性 V3 抗体。因此，这些 V3 稳定的 SOSIP 三聚体可用于中和 V3 抗体反应。异源加强诱导 M4008_N1 样抗体反应我们将在兔子模型中检验我们的假设。使用一组精心选择的异源启动/增强策略中的最佳策略，我们有两个目标。 (1) 最佳免疫原组合的选择，(2)：兔免疫和表征该项目的预期结果是原理论证的证明。针对新发现的V3冠脆弱位点的免疫原性，为未来奠定基础广泛的免疫原性研究，包括潜在的非人类灵长类动物研究。