Humoral Correlates of Protection Against HIV

预防艾滋病毒的体液相关性

• 批准号: 8662186
• 负责人: Ruth Margrit Ruprecht
• 金额: $ 79.97万
• 依托单位: TEXAS BIOMEDICAL RESEARCH INSTITUTE
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-06-08 至 2017-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8662186
• 关键词: AIDS Vaccines; AIDS/HIV problem; Acquired Immunodeficiency Syndrome; Address; Amino Acid Sequence; Amino Acids; Antibodies; Antibody Formation; Antigens; Antiviral Agents; B-Lymphocytes; Bacteriophages; Cellular Immunity; Dose; Engineering; Epitopes; Failure; Flow Cytometry; Future; Gagging; Generations; Genes; HIV; Human; Humoral Immunities; Immunity; Immunization; Immunoglobulin Variable Region; Individual; Infection; Interferons; Label; Light; Link; Macaca mulatta; Modeling; Monkeys; Monoclonal Antibodies; Passive Immunization; Peptide Library; Plasma; Primates; Random Peptide Libraries; Recombinant Antibody; Recombinant Proteins; Recombinants; Reporting; Risk; SIV; Serum; Specificity; Sum; Systemic infection; Technology; Testing; Time; Vaccinated; Vaccines; Viral; Viremia; Virus; Virus Diseases; base; cohort; design; gp160; immunogenicity; improved; in vivo; neutralizing antibody; novel; novel strategies; particle; polyclonal antibody; preclinical study; recombinant peptide; research study; response; simian human immunodeficiency virus; tool; viral RNA

DESCRIPTION (provided by applicant): The 31.2% decrease in HIV acquisition reported in the RV144 trial has raised hopes that vaccine protection may be achievable. We have pursued a bimodal vaccine approach to induce both cellular and humoral immunity; in our recent rhesus macaque (RM) study, recombinant protein immunogens (SIV Gag-Pol particles, HIV Tat, and multimeric HIV clade C (HIV-C) gp160) provided complete protection for some RMs against multiple intrarectal challenges with a heterologous R5 clade C SHIV (SHIV-C). Our study simultaneously linked cellular as well as humoral antiviral immunity to protection. Overall, five vaccine-protected RMs remained free of persistent, systemic infection; all had generated high-titer neutralizing antibodies (nAbs) in response to multimeric gp160 of an HIV-C strain that diverged by 22.2% in amino acid sequence from Env of the challenge virus. Our overall hypothesis is that vaccine-induced Abs - either nAbs and/or Abs with antiviral effector functions - can protect against heterologous virus acquisition. We have developed new tools to determine the epitope specificity of protective Abs from polyclonal sera. Our strategy involves a) differentil biopanning with recombinant peptide libraries to isolate mimotopes linked to protection, b) isolation of single RM B cells specific for a given mimotope/epitope, 3) PCR amplification of RM immunoglobulin variable regions, and 4) generation of recombinant Abs. These novel approaches have led to the isolation of two new chimeric simian/human nmAbs with predicted epitope specificity. We now seek to use these new tools for the following Specific Aims: 1. to characterize the epitopes recognized by polyclonal Abs of vaccine-protected RMs by differential biopanning. First, we will positively select recombinant phages encoding random peptide libraries by biopanning with plasma from a vaccine-protected RM, followed by negative counter-selection with plasma from vaccinated, unprotected RMs. After several rounds of positive/negative selection, recombinant phages will reflect mimotopes linked to protection. We will also address the converse question: did RMs with vaccine failure mount unfavorable Ab responses that are not found in vaccine-protected RMs - or is failure simply a lack of protection-linked Abs? To do this, we will reverse the biopanning strategy and characterize the cognate epitopes linked to vaccine failure. 2. to isolate antigen-specific single B cells from the protecte RMs and PCR amplify the heavy/light chain variable immunoglobulin regions, using our newly generated RM-specific primers. 3. to perform passive immunization in RMs with the novel mAbs to demonstrate protection against mucosal challenge with a heterologous R5 SHIV. Our studies, which are based upon a well-characterized cohort of vaccine-protected RMs given upfront heterologous SHIV-C challenges, will identify epitopes that are protective or perhaps also deleterious in vivo and therefore provide important information for future HIV/AIDS immunogen design and optimization.

描述（由申请人提供）：RV144 试验中报告的 HIV 感染率下降了 31.2%，这给人们带来了疫苗保护可能实现的希望。我们采用双模式疫苗方法来诱导细胞免疫和体液免疫；在我们最近的恒河猴 (RM) 研究中，重组蛋白免疫原（SIV Gag-Pol 颗粒、HIV Tat 和多聚体 HIV C 分支 (HIV-C) gp160）为一些 RM 提供了完全保护，以抵御异源 R5 分支 C SHIV (SHIV-C) 的多重直肠内攻击。我们的研究同时将细胞和体液抗病毒免疫与保护联系起来。总体而言，五名受疫苗保护的 RM 仍未出现持续性全身感染；所有这些都产生了高滴度的中和抗体（nAb），以响应 HIV-C 毒株的多聚体 gp160，该毒株的氨基酸序列与攻击病毒的 Env 存在 22.2% 的差异。我们的总体假设是疫苗诱导的抗体（nAb 和/或具有抗病毒效应功能的抗体）可以防止异源病毒获得。我们开发了新工具来确定多克隆血清中保护性抗体的表位特异性。我们的策略包括a) 使用重组肽文库进行差异生物淘选，以分离与保护相关的模拟表位，b) 分离对给定模拟表位/表位特异的单个 RM B 细胞，3) RM 免疫球蛋白可变区的 PCR 扩增，以及 4) 重组抗体的生成。这些新颖的方法已分离出两种具有预测表位特异性的新型嵌合猿/人 nmAb。我们现在寻求将这些新工具用于以下具体目标： 1. 通过差异生物淘选来表征疫苗保护的 RM 的多克隆抗体所识别的表位。首先，我们将通过使用来自疫苗保护的 RM 的血浆进行生物淘选来正选择编码随机肽文库的重组噬菌体，然后使用来自接种疫苗的未保护的 RM 的血浆进行负反选择。经过几轮正/负选择后，重组噬菌体将反映与保护相关的模拟表位。我们还将解决相反的问题：疫苗失败的 RM 是否会产生在疫苗保护的 RM 中未发现的不利抗体反应 - 或者失败仅仅是缺乏与保护相关的 Abs？为此，我们将逆转生物淘选策略并表征与疫苗失败相关的同源表位。 2. 使用我们新生成的 RM 特异性引物，从受保护的 RM 中分离抗原特异性单个 B 细胞，并通过 PCR 扩增重链/轻链可变免疫球蛋白区域。 3. 使用新型单克隆抗体对 RM 进行被动免疫，以证明对异源 R5 SHIV 的粘膜攻击具有保护作用。我们的研究基于预先接受异源 SHIV-C 挑战的疫苗保护 RM 队列，将鉴定体内具有保护性或可能有害的表位，从而为未来的 HIV/AIDS 免疫原设计和优化提供重要信息。