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Germline-Specific Immunogens for the Induction of Neutralizing Antibodies to HIV-

用于诱导 HIV 中和抗体的种系特异性免疫原

基本信息

批准号：
8329484
负责人：
Robert G. Whalen
金额：
$ 30万
依托单位：
ALTRAVAX, INC.
依托单位国家：
美国
项目类别：
财政年份：
2012
资助国家：
美国
起止时间：
2012-07-02 至 2014-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8329484
关键词：
AIDS/HIV problem Affinity Antibodies Antibody Binding Sites Antibody Formation Antibody Specificity Antigens Appearance Area B-Cell Activation B-Lymphocytes Binding Binding Sites Cause of Death Cell surface Cells Coupled Data Directed Molecular Evolution Disease Epidemic Epitopes Family Future Genetic Recombination Genomics Globulins Goals HIV HIV Envelope Protein gp120 HIV-1 Human Immune system Immunization Immunoglobulin Genes Immunoglobulins In Vitro Individual Infection Infection prevention Influenza Investigation Libraries Life Measures Methods Modeling Monoclonal Antibodies Multiple Myeloma Mutate Parents Phase Production Protein Binding Proteins Reagent Research Proposals Screening procedure Series Small Business Innovation Research Grant Specificity Structure Surface Surface Immunoglobulins Testing Vaccination Vaccine Research Vaccines Variant Virus Work base candidate identification design env Gene Products env Glycoproteins human monoclonal antibodies innovation insight neutralizing antibody neutralizing monoclonal antibodies pathogen polyclonal antibody prevent response success three dimensional structure vaccine candidate

项目摘要

DESCRIPTION (provided by applicant): Vaccines are urgently needed to slow the spread of the HIV/AIDS epidemic, and immunogens that can induce neutralizing antibodies remain an important goal of vaccine research. An increasing number of human monoclonal antibodies (mAbs) have been isolated in recent years from individuals who show remarkably broad and potent neutralizing responses. Coupled with past work, these results support the idea that the human immune system can generate rare but potent protective antibodies to the virus. Much work, including our own, has focused on identifying forms of the HIV-1 envelope glycoprotein (Env) that bind to broadly neutralizing antibodies. In contrast to approaches that optimize Env for binding to these highly affinity-matured antibodies, we and others now propose to identify immunogens that can bind to the germline form of the broadly neutralizing antibodies as a more productive approach to immunization. While three-dimensional structures of antibody-antigen interactions have informed antigen design, the corresponding germline antibody sequences rarely show any binding to the HIV-1 Env. As a result, structural information is not readily available for rational design of germline immunogens. We propose therefore to employ a directed molecular evolution approach to the problem of identifying germline-specific immunogens. Such immunogens could stimulate immature B cells that carry the germline precursor of a mature broadly neutralizing antibody. Because any individual germline sequence represents only a few percent of all rearranged immunoglobulin genes, activating specific B cells with germline-specific immunogens could increase the likelihood of inducing an appropriate antibody. One can also envision using a series of immunogens that stimulate partially affinity-matured antibodies along a particular path to form a mature neutralizing antibody. The recently characterized VRC01 mAb is well suited to this approach, notably because the CDRH3 domain is less important for the neutralization activity compared to most of the other broadly neutralizing mAbs. This minimizes one of the constraints in predicting the structure of the germline VRC01 precursor. We will create a number of VRC01-like mAbs that are increasing reverted to the germline sequence and use these as reagents to screen libraries of Env variants created by in vitro homologous DNA recombination. The revertants can be used in a stepwise recursive fashion, whereby Env variants that bind minimally reverted mAbs can be used as parents to create libraries of additional variants for screening with more highly reverted forms. We will evaluate the ability of these germline-specific Env immunogens to bind to myeloma cells that express VRC01-like germline antibodies on the cell surface, an interaction that resembles one of the first steps of B-cell activation. This Proposal represents an innovative approach to the identification of candidate immunogens for HIV-1 vaccines. It has general applicability to other pathogens for which protective (or broadly protective) mAbs have been identified (e.g., RSV or influenza) but induction of those antibody specificities has proven problematic. PUBLIC HEALTH RELEVANCE: The HIV/AIDS epidemic continues to cause death and new infections with some 33 million people living with the disease. A vaccine that can reduce infection is an essential component of preventative measures. This research proposal is designed to create vaccine candidates that can prevent the HIV virus from infecting cells.

描述（申请人提供）：迫切需要疫苗来减缓艾滋病毒/艾滋病流行的传播，而能够诱导中和抗体的免疫原仍然是疫苗研究的重要目标。近年来，越来越多的人单克隆抗体 (mAb) 从表现出非常广泛和有效的中和反应的个体中分离出来。结合过去的工作，这些结果支持了这样的观点，即人类免疫系统可以产生罕见但有效的病毒保护性抗体。许多工作，包括我们自己的工作，都集中在识别与广泛中和抗体结合的 HIV-1 包膜糖蛋白 (Env) 的形式。与优化 Env 以与这些高度亲和力成熟的抗体结合的方法相比，我们和其他人现在建议鉴定可以与广泛中和抗体的种系形式结合的免疫原，作为更有效的免疫方法。虽然抗体-抗原相互作用的三维结构为抗原设计提供了信息，但相应的种系抗体序列很少显示出与 HIV-1 Env 的任何结合。因此，结构信息不易用于种系免疫原的合理设计。因此，我们建议采用定向分子进化方法来解决识别种系特异性免疫原的问题。这种免疫原可以刺激携带成熟广泛中和抗体种系前体的未成熟 B 细胞。由于任何单个种系序列仅代表所有重排免疫球蛋白基因的百分之几，因此用种系特异性免疫原激活特定 B 细胞可以增加诱导适当抗体的可能性。人们还可以设想使用一系列免疫原，沿着特定路径刺激部分亲和力成熟的抗体，以形成成熟的中和抗体。最近表征的 VRC01 mAb 非常适合这种方法，特别是因为与大多数其他广泛中和的 mAb 相比，CDRH3 结构域对于中和活性的重要性较低。这最大限度地减少了预测种系 VRC01 前体结构的限制之一。我们将创建许多类似 VRC01 的单克隆抗体，这些单克隆抗体越来越多地恢复到种系序列，并使用它们作为试剂来筛选通过体外同源 DNA 重组创建的 Env 变体文库。回复体可以以逐步递归的方式使用，其中结合最低程度回复的mAb的Env变体可以用作亲本，以创建其他变体的文库，用于筛选更高程度回复的形式。我们将评估这些种系特异性 Env 免疫原与在细胞表面表达 VRC01 样种系抗体的骨髓瘤细胞结合的能力，这种相互作用类似于 B 细胞激活的第一步。该提案代表了一种识别 HIV-1 疫苗候选免疫原的创新方法。它对已确定具有保护性（或广泛保护性）单克隆抗体的其他病原体（例如 RSV 或流感）具有普遍适用性，但事实证明诱导这些抗体特异性存在问题。公共卫生相关性：艾滋病毒/艾滋病流行继续导致死亡和新感染，约有 3300 万人患有这种疾病。可以减少感染的疫苗是预防措施的重要组成部分。该研究计划旨在创造能够防止艾滋病毒感染细胞的候选疫苗。