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

• 批准号: 10326698
• 负责人: Maria Victoria Filsinger Interrante
• 金额: $ 3.85万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 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/10326698
• 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; 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/antagonist; interest; mimetics; monomer; neutralizing antibody; novel; pandemic disease; peptidomimetics; response; scaffold; therapeutic target; unpublished works

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 In recent unpublished work, our group has identified a novel epitope for antibody-mediated neutralization in the prehairpin intermediate (PHI) of Env exposed during HIV viral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.

项目总结 艾滋病毒大流行是我们这个时代最深刻的全球人类健康挑战之一，有7500万人 自19811以来，有3,200万人死于与艾滋病有关的疾病。尽管经过了几十年的不懈努力，一个 有效的疫苗仍然难以捉摸。虽然患者来源的发现和特征广泛 针对HIV包膜蛋白(Env)不同表位的中和抗体(BNAbs)证明了这种抑制作用 人类抗体对病毒的作用是可能的，但这些抗体还不可能用疫苗诱导， 部分由于它们广泛的体细胞超突变(SHM)或长重链第三互补 确定区域(CDRH3)。 在最近未发表的工作中，我们小组发现了一个新的表位，用于抗体介导的中和 在HIV病毒融合过程中暴露的Env的发夹前中间体(PHI)，表明先前发现的 患者来源的抗体具有94%的种系同源性(A2)结合在CHR保守的螺旋面上，并且 亲和成熟后，在体外中和多个分支的1B层病毒。结构舒适性的有限程度 中和抗体和生殖系推测的版本与原始表位结合的能力表明 有可能从生殖系中诱导出针对该表位的中和抗体。此外，我们发现， 蛋白抑制剂5-Helix通过相同的螺旋chr表位结合和抑制，能够交叉。 中和1级、2级和3级HIV-1病毒。 综上所述，这些数据提供了这项工作的中心假设：对此更高亲和力的抗体 如果确定了表位，可能能够有效地跨分支中和。鉴于A2和5-螺旋都抑制 通过以折叠的𝛼-螺旋形式与CHR结合，这种二级结构在尝试 识别额外的CHR导向的中和抗体。因此，我计划使用C34线圈，这是一种螺旋肽的模拟物 Chr由19个氨基酸组成，来自Chr保守面，嫁接到Gcn4亮氨酸的一个单体上 拉链二聚体，以研究该表位上抗体介导的中和作用。这项研究的长期目标是 是为了研究chr的高度保守的螺旋面作为一种潜在的hiv-1免疫原能够诱导 广泛的中和抗体。在拟议的工作中，我将(I)识别和描述其他人类来源的 与C34线圈结合的单抗，(Ii)研究C34线圈对小鼠血清和记忆B细胞的反应 以及(Iii)测定人类幼稚B细胞对C34线圈的反应性。 总而言之，这项建议旨在调查这样一种假设，即高亲和力的螺旋状CHR抗体，如果 被识别的，可能能够有效地跨分支中和。这些研究将向人们提供潜在的 该表位的支架螺旋模拟物，以诱导针对HIV疫苗的中和抗体并引导 理性免疫原设计的未来迭代。