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了31.2%，这增加了疫苗保护可能实现的希望。我们一直在寻求一种双模式疫苗方法来诱导细胞和体液免疫；在我们最近的猕猴(RM)研究中，重组蛋白免疫原(SIV Gag-Pol颗粒、HIV Tat和多聚体HIV分支C(HIV-C)gp160)为一些RMS提供了完全保护，使其免受异源R5分支C Shiv(SHIV-C)的直肠内多重攻击。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，5个疫苗保护的RMS没有持续的系统性感染；所有的都产生了对HIV-C毒株的多聚体gp160的高滴度中和抗体(NAB)，该毒株的氨基酸序列与挑战病毒的env有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--可以预防异源病毒感染。我们已经开发了新的工具来确定来自多克隆血清的保护性抗体的表位特异性。我们的策略包括a)用重组多肽文库进行区分生物筛选以分离与保护相关的模拟表位，b)分离针对给定模拟表位/表位的单个rM B细胞，3)扩增rM免疫球蛋白可变区，以及4)产生重组抗体。这些新的方法导致了两个新的具有预测表位特异性的嵌合猿猴/人nmAbs的分离。我们现在寻求将这些新工具用于以下特定目的：1.通过差异生物扫描鉴定疫苗保护的RMS的多克隆抗体识别的表位。首先，我们将通过用疫苗保护的RM的血浆进行生物扫描来正向选择编码随机肽库的重组噬菌体，然后用来自疫苗接种的未保护的RMS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RMS是否产生了疫苗保护的RMS中没有的不利的抗体反应--或者失败仅仅是缺乏保护相关的抗体？为此，我们将逆转生物扫描策略，并确定与疫苗失败有关的同源表位的特征。2.从受保护的RMS中分离抗原特异的单个B细胞，利用我们新开发的Rm特异性引物，通过PCR扩增免疫球蛋白的重链/轻链可变区。3.用新的单抗在RMS中进行被动免疫，以显示对异源R5Shiv黏膜攻击的保护作用。我们的研究基于一组具有良好特征的疫苗保护的RMS，预先给予了异源SIV-C挑战，将识别在体内具有保护性或可能也是有害的表位，因此为未来HIV/AIDS免疫原的设计和优化提供重要信息。