Immunogenicity of the newly identified V3 crown vulnerable site

新发现的 V3 冠脆弱位点的免疫原性

• 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
• 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

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包膜(Env)的抗体(Ab)反应定义的易受攻击的部位 通过广泛中和抗体(BNAbs)可能会产生保护性疫苗。许多HIV bNAb已经被 发现了它们的表位，并在Env表面仔细绘制了它们的表位，这些表位 被归类为许多具有良好特征的类别。然而，对bNab的持续诱导 针对目前特征良好的易受攻击站点中的任何一个进行响应仍然是极其困难的，因为 这些bNAb及其相关的易受攻击部位的不寻常特征，例如需要长时间的 CDR H3，以穿透Env刺激物的葡聚糖膜。因此，通过以下方式识别其他易受攻击站点 合理靶向的有利特性可能有助于提高我们诱导bNab的能力 回应。我们最近通过绘制bNab M4008_N1和bNab M4008_N1的表位发现了一个新的易受攻击部位 鉴定其抗体与抗原的相互作用。M4008_N1是一种bNab，可以中和大约40%的 测试的主要分离株及其谱系类别都转换为免疫球蛋白和免疫球蛋白A。我们通过冷冻-EM展示了 M4008_N1的表位集中在gp120的第三个可变环(V3)的冠区 Env Trimer。M4008_N1表位的独特特性及其与V3冠状结构的相互作用方式 建议一种策略，通过V3启动和异源增强来诱导M4008_N1样抗体应答 稳定的环境三聚体。正如我们之前已经证明的，V3冠状抗体的反应相对 由V3免疫原直接诱导。因此，我们假设，由于V3冠-发夹是一个 共同的结构和M4008_N1可以结合V3环本身，抗体通过β- 像M4008_N1一样的片状相互作用可以由V3免疫原和这种M4008_N1样物诱导 然后可以用V3稳定的Env三聚体进行后续免疫来增强抗体反应， 它包含了bNab M4008_N1的全部表位。已知SOSIP免疫原的早期版本 诱导非中和V3抗体，但一些V3稳定版本似乎能够清除非中和V3抗体 中和V3抗体反应。因此，这些V3稳定的SOSIP三聚体可用于 异源Boost诱导M4008_N1类抗体应答。我们将在兔子模型中验证我们的假设 在异质素数/升压策略中使用一套精心选择的最优策略，我们有两个目标。 (1)最佳免疫原组合的筛选；(2)兔免疫及其特性的研究 抗体反应。该项目的预期成果是对 针对新发现的V3冠状易损部位的免疫原性，为以后的研究奠定基础 广泛的免疫原性研究，包括潜在的非人类灵长类研究。