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）：RV 144试验中报告的HIV感染率下降31.2%，这使人们对疫苗保护可能是可实现的抱有希望。我们已经采用了一种双模式疫苗方法来诱导细胞和体液免疫;在我们最近的恒河猴（RM）研究中，重组蛋白免疫原（SIV Gag-Pol颗粒、HIV达特和多聚体HIV进化枝C（HIV-C）gp 160）为一些RM提供了完全保护，使其免受异源R5进化枝C SHIV（SHIV-C）的多次直肠内攻击。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，5个疫苗保护RM仍然没有持续性全身感染;所有人都产生了高滴度中和抗体（nAb），以响应HIV-C株的多聚体gp 160，其氨基酸序列与攻击病毒的Env偏离22.2%。我们的总体假设是，疫苗诱导的抗体-无论是nAb和/或抗病毒效应功能的抗体-可以防止异源病毒的收购。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Ab的表位特异性。我们的策略包括a）用重组肽文库进行差异生物淘选以分离与保护连接的模拟表位，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，和4）重组Ab的产生。这些新的方法已经导致分离出两种新的具有预测表位特异性的嵌合猿/人nmAbs。我们现在寻求使用这些新工具实现以下具体目标：1.通过差异生物淘选表征疫苗保护RM的多克隆Ab识别的表位。首先，我们将通过用来自疫苗保护的RM的血浆进行生物淘选，然后用来自接种疫苗的未保护的RM的血浆进行阴性反选择来阳性选择编码随机肽文库的重组cDNA。经过几轮阳性/阴性选择后，重组体p53将反映与保护相关的模拟表位。我们还将解决匡威的问题：疫苗失败的RM是否会产生疫苗保护RM中未发现的不利Ab应答-或者失败仅仅是缺乏保护相关Ab？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.从保护性RM中分离抗原特异性单个B细胞，并使用我们新产生的RM特异性引物PCR扩增重/轻链可变免疫球蛋白区。3.在RM中用新型mAb进行被动免疫，以证明对异源R5 SHIV粘膜攻击的保护作用。我们的研究，这是基于一个良好的特征队列的疫苗保护RM给予前期异源SHIV-C的挑战，将确定表位是保护性的，也可能是有害的体内，因此提供了重要的信息，为未来的HIV/AIDS免疫原的设计和优化。