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: 10646412
• 负责人: Maria Victoria Filsinger Interrante
• 金额: $ 1.64万
• 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/10646412
• 关键词: Acquired Immunodeficiency Syndrome; Affinity; Amino Acids; Antibodies; Antibody Affinity; Antibody Response; Antibody-mediated protection; Antigens; Area; B-Lymphocytes; Binding; Cell Separation; Clinical Trials; Conserved Sequence; Data; Dedications; Enzyme-Linked Immunosorbent Assay; Epitope Mapping; Epitopes; FDA approved; Face; Future; Goals; HIV; HIV envelope protein; HIV vaccine; HIV-1; HIV/AIDS; Health; Human; Immunoglobulin Somatic Hypermutation; Immunologics; In Vitro; Individual; Infection; Leucine Zippers; Libraries; Mediating; Memory B-Lymphocyte; Molecular Conformation; Monoclonal Antibodies; Patients; Peripheral Blood Mononuclear Cell; Persons; Process; Proteins; Research; Scaffolding Protein; Serum; Sorting; Structure; T-20; Testing; Time; Vaccines; Viral; Virus; Work; X-Ray Crystallography; alpha helix; 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monomer; neutralizing antibody; novel; pandemic disease; peptidomimetics; response; scaffold; therapeutic target; unpublished works

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 In recent unpublished work, our group has identified a novel epitope for antibody-mediated neutralization in the prehairpin intermediate (PHI) of Env exposed during HIV viral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

项目摘要 艾滋病毒大流行病是我们时代最深刻的全球人类健康挑战之一， 自1981年以来，有3200万人感染艾滋病，3200万人死于与艾滋病有关的疾病。尽管经过几十年的努力， 有效的疫苗仍然是难以捉摸的。虽然发现和表征的病人来源广泛， 针对HIV包膜蛋白（Env）的各种表位的中和抗体（bnAb）证明， 病毒的抗体是可能的，这些抗体还不可能用疫苗引发， 部分由于它们广泛的体细胞超突变（SHM）或长重链第三互补性 决定区（CDRH 3）。 在最近未发表的工作中，我们的小组已经确定了一个新的表位，用于抗体介导的中和， 在HIV病毒融合过程中暴露的Env的前发夹中间体（PHI），表明先前发现的 具有94%生殖系同一性的患者来源抗体（A2）结合至DNA的保守螺旋面，并且 亲和力成熟后，在体外中和多个进化枝中的1B级病毒。有限的SHM程度 中和抗体和种系推断的形式结合原始表位的能力表明， 可以从种系中引发针对该表位的中和抗体。此外，我们发现， 蛋白抑制剂5-HSP 70通过相同的螺旋HSP 70表位结合和抑制，能够交叉进化枝 中和1、2和3级HIV-1病毒。 总之，这些数据告知这项工作的中心假设：高亲和力的抗体， 表位，如果鉴定的话，可能能够有效的交叉进化枝中和。考虑到A2和5-羟色胺都抑制 HIV融合通过结合到作为折叠的β-螺旋的β-螺旋上，这种二级结构可能在尝试 鉴定另外的针对CHR的中和抗体。因此，我计划使用C34 coil，一种螺旋肽模拟物， 所述双链体包含来自接枝到GCN 4亮氨酸的一个单体上的双链体保守面的19个氨基酸 拉链二聚体，以研究在该表位处的抗体介导的中和。这项研究的长期目标是 是研究高度保守的，螺旋面作为一个潜在的HIV-1免疫原，能够引发 广泛中和抗体。在拟议的工作中，我将（i）确定和表征额外的人源性 结合C34螺旋的单克隆抗体，（ii）研究血清和记忆B细胞对C34螺旋的应答， HIV-1感染的个体，和（iii）测定人幼稚B细胞对C34螺旋的反应性。 总的来说，这项建议的目的是调查的假设，高亲和力抗体的螺旋区，如果 鉴定，可能能够有效的交叉进化枝中和。这些研究将为潜在的 构建该表位的螺旋模拟物，以引发针对HIV疫苗的中和抗体，并引导 合理免疫原设计的未来迭代。