Characterization of the human antibody response to a novel neutralizing HIV-1 epitope

人类抗体对新型中和 HIV-1 表位反应的表征

基本信息

批准号：
10457292
负责人：
Maria Victoria Filsinger Interrante
金额：
$ 3.92万
依托单位：
STANFORD UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-07-01 至 2023-09-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/10457292
关键词：
AIDS/HIV problem Acquired Immunodeficiency Syndrome Affinity Amino Acids Antibodies Antibody Affinity Antibody Response Antibody-mediated protection Antigens Area B-Lymphocytes Binding Cells Clinical Trials Conserved Sequence Data Enzyme-Linked Immunosorbent Assay Epitope Mapping Epitopes FDA approved Face Future Goals HIV HIV envelope protein HIV vaccine HIV-1 Health Human Immunoglobulin Somatic Hypermutation Immunologics In Vitro Individual Infection Leucine Zippers Mediating Memory B-Lymphocyte Molecular Conformation Monoclonal Antibodies Patients Peripheral Blood Mononuclear Cell Persons Process Proteins Research Scaffolding Protein Serum Structure T-20 Testing Time Vaccines Viral Virus Work X-Ray Crystallography chronic infection cohort complementarity-determining region 3 design dimer env Gene Products experimental study inhibitor interest mimetics monomer neutralizing antibody novel pandemic disease peptidomimetics response scaffold therapeutic target unpublished works

项目摘要

PROJECT SUMMARY The HIV pandemic is one of the most profound global human health challenges of our time, with 75 million people infected and 32 million dead from AIDS-related illnesses since 19811. Despite decades of dedicated efforts, an effective vaccine has remained elusive. While the discovery and characterization of patient-derived broadly neutralizing antibodies (bnAbs) to various epitopes of the HIV envelope protein (Env) demonstrate that inhibition of the virus by human antibodies is possible, these antibodies have not yet been possible to elicit with a vaccine, due in part to their extensive somatic hypermutation (SHM) or long heavy-chain third complementarity determining regions (CDRH3s). In recent unpublished work, our group has identified a novel epitope for antibody-mediated neutralization in the prehairpin intermediate (PHI) of Env exposed during HIV viral fusion, demonstrating that a previously discovered patient-derived antibody with 94% germline identity (A2) binds to the conserved, helical face of the CHR, and after affinity maturation neutralizes tier-1B viruses across multiple clades in vitro. The limited degree of SHM of the neutralizing antibody and the ability of a germline-inferred version to bind to the original epitope suggest that it may be possible to elicit neutralizing antibodies to this epitope from the germline. In addition, we found that the protein inhibitor 5-Helix, which binds and inhibits via the same helical CHR epitope, is capable of cross-clade neutralization of tier-1, -2, and -3 HIV-1 viruses. Taken together, these data inform the central hypothesis of this work: that higher-affinity antibodies to this epitope, if identified, may be capable of effective cross-clade neutralization. Given that both A2 and 5-Helix inhibit HIV fusion by binding to the CHR as a folded 𝛼-helix, this secondary structure is likely important in attempts to identify additional CHR-directed neutralizing antibodies. Thus, I plan to use C34coil, a helical peptide mimetic of the CHR comprising 19 amino acids from the CHR conserved face grafted onto one monomer of a GCN4 leucine zipper dimer, to investigate antibody-mediated neutralization at this epitope. The long-term goal of this research is to investigate the highly-conserved, helical face of the CHR as a potential HIV-1 immunogen capable of eliciting broadly neutralizing antibodies. In the proposed work, I will (i) identify and characterize additional human-derived monoclonal antibodies that bind to C34coil, (ii) investigate the serum and memory B cell response to C34coil in HIV-1 infected individuals, and (iii) determine human naïve B cell reactivity to C34coil. Collectively, this proposal aims to investigate the hypothesis that high-affinity antibodies to the helical CHR, if identified, may be capable of effective cross-clade neutralization. These studies will inform the potential of a scaffolded, helical mimetic of this epitope to elicit neutralizing antibodies towards an HIV vaccine and guide future iterations of rational immunogen design.

项目概要艾滋病毒大流行是当今时代最深刻的全球人类健康挑战之一，影响了 7500 万人自 19811 年以来，已有 3200 万人感染艾滋病，并有 3200 万人死于艾滋病相关疾病。尽管经过数十年的不懈努力，有效的疫苗仍然难以捉摸，而源自患者的广泛疫苗的发现和表征。 HIV 蛋白 (Env) 各种包膜表位的中和抗体 (bnAbs) 证明，抑制人类抗体对病毒的抵抗是可能的，但这些抗体尚未可能通过疫苗产生，部分原因是它们广泛的体细胞超突变（SHM）或长重链第三互补性确定区域（CDRH3）。在最近未发表的工作中，我们的小组在抗体介导的中和中鉴定了一个新的表位 HIV 病毒融合过程中暴露的 Env 前发夹中间体 (PHI)，证明先前发现的具有 94% 种系同一性 (A2) 的患者衍生抗体与 CHR 的保守螺旋面结合，并且亲和力成熟后，在体外中和跨多个进化枝的 1B 级病毒。中和抗体以及种系推断版本与原始表位结合的能力表明可能会从种系中引发针对该表位的中和抗体。蛋白质抑制剂 5-Helix 通过相同的螺旋 CHR 表位结合并抑制，能够跨进化枝中和 1 级、-2 级和-3 级 HIV-1 病毒。总而言之，这些数据揭示了这项工作的中心假设：对此具有更高亲和力的抗体鉴于 A2 和 5-Helix 都抑制，表位如果被鉴定，可能能够有效地进行跨进化枝中和。 HIV 融合通过以折叠的 𝛼 螺旋形式与 CHR 结合，这种二级结构可能在尝试因此，我计划使用 C34coil，一种螺旋肽模拟物。包含来自CHR保守面的19个氨基酸的CHR嫁接到GCN4亮氨酸的一个单体上拉链二聚体，研究该表位的抗体介导的中和作用是本研究的长期目标。的目的是研究 CHR 的高度保守的螺旋面作为一种潜在的 HIV-1 免疫原，能够引发在拟议的工作中，我将（i）识别并表征其他人源性抗体。结合 C34 线圈的单克隆抗体，(ii) 研究血清和记忆 B 细胞对 C34 线圈的反应 HIV-1 感染个体，以及 (iii) 确定人类幼稚 B 细胞对 C34 线圈的反应性。总的来说，该提案旨在研究以下假设：螺旋 CHR 的高亲和力抗体，如果已确定，可能能够有效地进行跨分支中和，这些研究将揭示一种潜力。该表位的支架式螺旋模拟物可引发针对 HIV 疫苗的中和抗体并指导合理免疫原设计的未来迭代。