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）：在RV144试验中报告的艾滋病毒感染减少31.2%，增加了疫苗保护可能实现的希望。我们已经采用双峰疫苗方法来诱导细胞免疫和体液免疫；在我们最近对恒河猴（RM）的研究中，重组蛋白免疫原（SIV Gag-Pol颗粒、HIV Tat和多聚型HIV进化枝C (HIV-C) gp160）为一些恒河猴提供了完全的保护，使其免受来自异种R5进化枝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。总的来说，5个疫苗保护的RMs仍然没有持续的全身性感染；所有人都产生了高滴度中和抗体（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差异22.2%。我们的总体假设是，疫苗诱导的抗体-无论是抗体和/或具有抗病毒效应功能的抗体-可以防止异源病毒获得。我们开发了新的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)用重组肽库进行差异性生物筛选，以分离与保护相关的mimotopes， b)分离单个RM b细胞特异性的给定mimotope/表位，3)PCR扩增RM免疫球蛋白可变区域，以及4)产生重组抗体。这些新方法导致分离出两种新的嵌合猴/人nmab抗体，具有预测的表位特异性。我们现在寻求利用这些新工具实现以下具体目标：通过鉴别生物筛检来鉴定疫苗保护RMs的多克隆抗体识别的表位。首先，我们将用疫苗保护的RM的血浆进行生物筛选，阳性选择编码随机肽库的重组噬菌体，然后用接种疫苗的未保护的RM的血浆进行阴性反选择。经过几轮阳性/阴性选择，重组噬菌体将反映与保护相关的模位。我们还将解决相反的问题：疫苗失败的RMs是否产生了疫苗保护RMs中没有的不利的抗体反应，或者失败仅仅是缺乏与保护相关的抗体？为此，我们将逆转生物筛选策略，对与疫苗失败相关的同源表位进行表征。2. 使用我们新生成的rm特异性引物，从保护rm中分离抗原特异性的单个B细胞，并PCR扩增重/轻链可变免疫球蛋白区域。3. 利用新型单克隆抗体对rm进行被动免疫，以证明对异种R5 SHIV的粘膜攻击具有保护作用。我们的研究基于一组具有良好特征的疫苗保护RMs，这些RMs事先接受了异源SHIV-C挑战，将确定体内保护或可能有害的表位，从而为未来的HIV/AIDS免疫原设计和优化提供重要信息。