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，能够逃脱免疫防御 由大多数疫苗诱导的抗体提供。提出的引发广泛中和抗体的策略 通过疫苗接种来预防bnAb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年的时间来开发。在HIV感染者中，病毒和 产生抗体的B细胞一起进化，产生病毒抗体“军备竞赛”， 抗体在整个感染过程中都存在。拟议的研究是分析关键的早期时间点， 一个捐赠者的军备竞赛，他开发出了广泛的抗体，以指导免疫原的设计。 除了快速突变，HIV还利用重糖基化和构象掩蔽来逃避 免疫系统.供体CH 848产生了一个称为DH 270的bnAb谱系，它与聚糖相互作用， 在HIV包膜（Env）可变环V3的基础上的“超位点”。配合物的晶体结构分析 HIV Env的成熟成员和片段之间的差异以及结合数据表明， 抗体中的突变导致不同分支中抗体的不同中和特性 在抗体互补位或抗原表位中没有任何主要的结构变化。虽然许多 V3-聚糖“超位点”bnAb识别N332聚糖，它们的实际表位在其他聚糖和Env中不同 它们识别的肽。因此，仍有待确定是什么触发了DH 270谱系的发展。 了解艾滋病毒的特性 Env和与抗体的相互作用对DH 270至关重要 谱系发展，HIV的原子分辨率结构 将通过冷冻电子显微镜测定Envs 和/或用DH 270谱系的早期成员DH270.IA4和与其合作的 抗体谱系成员，DH 475和DH 0022。协同抗体，也在CH 848供体中产生， 引发了病毒逃逸突变，改善了与DH 270谱系抗体的结合， 在DH 270谱系中的亲和力成熟。关于DH 270谱系祖细胞抗体如何结合的假设 Env也可以从DH270.IA4复合物结构推断，因为DH270.IA4不同于前体Env。 五种氨基酸。将通过将突变引入Fab和/或HIV Env中来检验假设， 通过生物层干涉测量法测定结合亲和力。与之复合的协同抗体的结构 Env将识别HIV Env的特性（即，构象、糖基化模式等）引发了这些非- 中和抗体，以及尽管它们的表位重叠，它们如何帮助DH 270谱系发育。 这些数据将确定引发广泛中和聚糖形成的机制， 依赖性抗体和指导疫苗设计。本科研究生支持这项赠款 一项提案将利用尖端技术探讨一个至关重要的公共卫生问题， 他们可以在已发表的作品上学习，并得到致力于长期职业发展的专家的指导。