Structure and immunogenicity of novel trimeric HIV-1 Env immunogens

新型三聚体 HIV-1 Env 免疫原的结构和免疫原性

• 批准号: 10020934
• 负责人: XIANGPENG KONG
• 金额: $ 76.7万
• 依托单位: NEW YORK UNIVERSITY SCHOOL OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-09-19 至 2024-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10020934
• 关键词: Acquired Immunodeficiency Syndrome; Animals; Antibody Formation; Antibody Response; Antigens; Binding Sites; Biological Assay; Complex; Computer Models; Cryoelectron Microscopy; DNA; Dental crowns; Development; Engineering; Epitopes; Extracellular Domain; Generations; Glycoproteins; Goals; HIV; HIV Envelope Protein gp120; HIV vaccine; HIV-1; Immune; Immunize; Immunologics; Individual; Macaca mulatta; Masks; Molecular Conformation; Oryctolagus cuniculus; Polysaccharides; Property; Protein Engineering; Proteins; Regimen; Resolution; Scaffolding Protein; Site; Specificity; Structure; Testing; Vaccine Design; Vaccines; Visualization; Work; base; design; immunogenic; immunogenicity; improved; infection risk; neutralizing antibody; novel; novel strategies; pandemic disease; scaffold; success; three-dimensional visualization; trimer core; vaccine development; virus envelope

A vaccine is needed to stop the HIV-1/AIDS pandemic, however, the development of a protective vaccine remains a great challenge and requires novel strategies. Various approaches to stabilize the whole extracellular domain of the HIV-1 envelope (Env) has led to greatly improved vaccine designs, e.g., the development of the SOSIP trimer, which, in addition to having provided a refined structural understanding of the Env trimer, is considered as a promising immunogen because it harbors all the known vulnerable sites on the Env trimer targeted by bnAbs. However, SOSIP-based immunogens have achieved only limited success due to unwanted distracting epitope sites that divert Ab responses to strain-specific ones. Unlike whole Env extracellular domain approaches, we have been using a divide-and-conquer strategy by starting with individual domains of the Env trimer to develop domain-specific immunogens which have the advantage of immune- focusing Ab responses to selected Env domains and epitopes and of avoiding induction of Abs to unwanted epitope regions. We started with the V1V2 domain, not only for its domain structure spatially located at the Env apex but also its Abs inversely correlate with the risk of infection in the RV144 trial, have developed a panel of trimeric V1V2 domain immunogens by scaffolding V1V2 of gp120 on trimeric non-HIV proteins, and demonstrated that they can induce V1V2-focused Ab responses. Moreover, further design efforts have resulted in a single chain tandem V1V2 trimer showing antigenic reactivity with trimer-specific bnAbs. We hypothesize that such V1V2-domain immunogens can be improved to present the native Env apex configuration by further structural characterization and engineering. To expand from the Env apex, we have then designed a ‘re-cored’ Env trimer immunogen by replacing the gp120 inner domain and gp41 in the prefusion trimer structure with a stable trimeric non-HIV scaffold protein; antigenicity tests demonstrated that this molecule harbors all key bnAb binding sites of the trimeric Env apex and EM visualization showed it to have a well-formed trimeric configuration. This novel construct provides a starting point to develop a trimeric immunogen that carries key vulnerable sites of the Env trimer which could become an attractive alternative to the SOSIP trimers, offering greater focus on the most promising bnAb epitopes. The goal of this R01 project is to structurally characterize these rationally-designed immunogens and further apply our structure-based platform to develop new generations of them so that they serve as effective immunogens targeting native trimeric configurations. We have three Aims. 1) Characterize and refine the trimeric V1V2-scaffold constructs mimicking the native prefusion conformation of the Env trimer apex. 2) Develop the re-cored Env trimer immunogen harboring key bnAb sites. 3) Test the immunogenicity of these refined immunogens in animals. At the completion of this project, our novel trimeric immunogens will be fully characterized and selected native-like immunogens can then be move forward in the pipeline for vaccine development and for NHP challenge studies.

需要一种疫苗来阻止 HIV-1/艾滋病的流行，但是保护性疫苗的开发 仍然是一个巨大的挑战，需要采取各种新的策略来稳定整体。 HIV-1 包膜 (Env) 的胞外结构域极大地改进了疫苗设计，例如 SOSIP 三聚体的开发，除了提供了对 Env 三聚体被认为是一种有前途的免疫原，因为它包含了所有已知的易受攻击的位点 然而，基于 SOSIP 的免疫原只取得了有限的成功。 与整个 Env 不同的是，由于不需要的干扰表位位点会将 Ab 反应转移到菌株特异性的反应上。 在细胞外域方法中，我们一直在使用分而治之的策略，从个体开始 Env 三聚体的结构域可开发具有免疫优势的结构域特异性免疫原 集中抗体对选定的 Env 结构域和表位的反应，并避免诱导抗体产生不需要的抗体 我们从 V1V2 结构域开始，不仅是因为它的结构域结构在空间上位于 Env。 在 RV144 试验中，apex 及其 Abs 与感染风险呈负相关，开发了一组 通过将 gp120 的 V1V2 支架固定在三聚体非 HIV 蛋白上，形成三聚体 V1V2 结构域免疫原，以及 此外，还进行了进一步的设计工作。 在单链串联 V1V2 三聚体中，显示与三聚体特异性 bnAb 的抗原反应性。 这样的V1V2域免疫原可以通过进一步改进来呈现天然的Env顶点构型 为了从环境顶点进行扩展，我们设计了一个“重新核心”。 Env三聚体免疫原通过用a替换预融合三聚体结构中的gp120内部结构域和gp41 稳定的三聚体非 HIV 支架蛋白；抗原性测试表明该分子包含所有关键的 bnAb 三聚体 Env apex 的结合位点和 EM 可视化显示其具有良好形成的三聚体 这种新颖的结构为开发携带关键的三聚体免疫原提供了起点。 Env 三聚体的脆弱位点可能成为 SOSIP 三聚体的有吸引力的替代品，提供 更加关注最有前途的 bnAb 表位 该 R01 项目的目标是对结构进行表征。 这些合理设计的免疫原，并进一步应用我们基于结构的平台来开发新的免疫原 它们可以作为针对天然三聚体构型的有效免疫原。 有三个目标 1) 表征和完善模仿天然的三聚体 V1V2 支架结构。 2) 开发包含密钥的重新核心的Env三聚体免疫原 bnAb 位点。 3) 测试这些精制免疫原在动物中的免疫原性。 项目中，我们的新型三聚体免疫原将得到充分表征，并且选定的天然样免疫原可以 然后推进疫苗开发和 NHP 挑战研究。