Analysis of the Initiation of an HIV Broadly Neutralizing Antibody Lineage in a Single Host

单一宿主中 HIV 广泛中和抗体谱系的启动分析

• 批准号: 10013493
• 负责人: Daniela Fera
• 金额: $ 32.92万
• 依托单位: SWARTHMORE COLLEGE
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-04-01 至 2024-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10013493
• 关键词: Affinity; Amino Acids; Antibodies; Antibody Binding Sites; Antigens; Applications Grants; B-Lymphocytes; Binding; Cells; Characteristics; Complementarity Determining Regions; Complex; Cryoelectron Microscopy; Crystallization; Data; Development; Epitopes; Evolution; Glycoproteins; Goals; HIV; HIV vaccine; Immune; Immune response; Immune system; Individual; Infection; Interferometry; KAI1 gene; Length; Masks; Mediating; Mentors; Molecular; Molecular Conformation; Mutation; Outcome; Pattern; Peptides; Polysaccharides; Population; Process; Property; Protein Region; Public Health; Publishing; Race; Regimen; Research; Resolution; Site; Structure; Students; Surface; Techniques; Testing; Time; Training; V3 Loop; Vaccination; Vaccine Design; Vaccines; Variant; Viral; Viral Antibodies; Virus; Work; X-Ray Crystallography; arm; base; career development; design; env Gene Products; glycosylation; improved; member; movie; mutant; neutralizing antibody; pathogen; prevent; progenitor; response; undergraduate research; vaccine development

Human immunodeficiency virus (HIV) is a rapidly evolving pathogen that escapes immune defenses provided by most vaccine-induced antibodies. Proposed strategies to elicit broadly neutralizing antibodies (bnAbs) by vaccination require a deeper understanding of evolution of the immune response to infection, since these protective antibodies typically take ~4-5 years to develop. In HIV infected individuals, viruses and antibody producing B-cells evolve together, creating a virus-antibody “arms race”, with populations of viruses and antibodies present throughout infection. The proposed research is to analyze critical early time-points of the arms race in a donor who developed antibodies of significant breadth, to guide immunogen design. In addition to rapid mutation, HIV also uses heavy glycosylation and conformational masking to evade the immune system. Donor CH848 produced a bnAb lineage, called DH270, which interacts with the glycan “supersite” at the base of the HIV envelope (Env) variable loop V3. Analysis of crystal structures of complexes between mature members and fragments of the HIV Env, together with binding data, suggest that improbable mutations in the antibodies led to the different neutralization properties of antibodies in the different branches of the lineage, without any major structural change in the antibody paratope or antigen epitope. While many V3-glycan “supersite” bnAbs recognize the N332 glycan, their actual epitopes differ in other glycans and Env peptides they recognize. Thus, it remains to be determined what triggered DH270 lineage development. To understand properties of HIV Env and interactions with antibodies that were critical for DH270 lineage development, atomic resolution structures of HIV Envs will be determined by cryo-electron microscopy and/or X-ray crystallography with an early member of the DH270 lineage, DH270.IA4, and with cooperating antibody lineage members, DH475 and DH0022. Cooperating antibodies, also produced in the CH848 donor, triggered virus escape mutations that improved binding to DH270 lineage antibodies and likely accelerated affinity maturation in the DH270 lineage. Hypotheses on how the DH270 lineage progenitor antibody could bind Env may also be deduced from the DH270.IA4 complex structure, since DH270.IA4 differs from the progenitor by five amino acids. Hypotheses will be tested by introducing mutations into the Fabs and/or HIV Env and determining binding affinities by biolayer interferometry. Structures of cooperating antibodies in complex with Env will identify properties of HIV Env (i.e., conformation, glycosylation patterns, etc.) that triggered these non- neutralizing antibodies, and despite their overlapping epitopes, how they aided DH270 lineage development. These data will identify mechanism(s) that triggered the development of broadly neutralizing glycan- dependent antibodies, and guide vaccine design. Undergraduate research students supported by this grant proposal will explore an issue of critical public health importance using cutting edge techniques, be co-authors on published work and be mentored by experts committed to their long-term career development.

人类免疫缺陷病毒 (HIV) 是一种快速进化的病原体，可以逃脱免疫防御 由大多数疫苗诱导的抗体提供的提议的引发广泛中和抗体的策略。 通过疫苗接种（bnAbs）需要更深入地了解对感染的免疫反应的演变，因为 这些保护性抗体通常需要约 4-5 年的时间才能在 HIV 感染者、病毒和感染者中形成。 产生抗体的 B 细胞一起进化，引发病毒与抗体的“军备竞赛” 以及整个感染过程中的抗体。拟议的研究是分析关键的早期时间点。 捐助者的军备竞赛开发了广泛的抗体，以指导免疫原设计。 除了快速突变外，HIV还利用重度糖基化和构象掩蔽来逃避 供体 CH848 产生了一种 bnAb 谱系，称为 DH270，它与聚糖相互作用。 HIV 包膜 (Env) 可变环 V3 底部的“超级位点”复合物晶体结构分析。 HIV 包膜的成熟成员和片段之间的研究以及结合数据表明，不太可能 抗体的突变导致不同分支的抗体具有不同的中和特性 谱系中，抗体互补位或抗原表位没有任何重大结构变化。 V3-聚糖“超级位点”bnAb 识别 N332 聚糖，其实际表位与其他聚糖和 Env 不同 因此，触发 DH270 谱系发育的因素仍有待确定。 了解艾滋病毒的特性 Env 以及与对 DH270 至关重要的抗体的相互作用 HIV的谱系发育、原子分辨率结构 Envs 将通过冷冻电子显微镜测定 和/或 DH270 谱系的早期成员 DH270.IA4 的 X 射线晶体学，以及与合作 抗体谱系成员，DH475和DH0022，也在CH848供体中产生， 触发病毒逃逸突变，改善与 DH270 谱系抗体的结合，并可能加速 DH270 谱系中的亲和力成熟关于 DH270 谱系祖抗体如何结合的假设。 Env 也可以从 DH270.IA4 复合体结构中推断出来，因为 DH270.IA4 不同于祖细胞 假设将通过在 Fab 和/或 HIV Env 中引入突变来检验。 通过生物层干涉测量法确定与复合物配合的抗体的结构。 Env 将识别 HIV Env 的特性（即构象、糖基化模式等），从而触发这些非- 中和抗体，以及尽管它们有重叠的表位，但它们如何帮助 DH270 谱系发育。 这些数据将确定触发广泛中和聚糖发展的机制。 依赖抗体和疫苗指南设计由该补助金支持。 提案将利用尖端技术探讨对公共卫生至关重要的问题，成为共同作者 发表的作品并接受致力于长期职业发展的专家的指导。