Humoral Correlates of Protection Against HIV

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。我们已经寻求一种双峰疫苗方法来诱导细胞和体液免疫，我们最近的恒河猴（RM）研究表明，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）在一些恒河猴（RM）中对异源进化枝C SHIV （SHIV-C）的多重攻击具有完全的保护作用。我们的研究同时将细胞和体液免疫反应与保护联系起来。总的来说，我们有五个疫苗保护的RMs仍然没有持续的全身性感染；它们都有高滴度中和抗体（nab），由多聚体gp160诱导，针对不同HIV-C毒株的SHIV-C编码env，与gp160免疫原相比差异为22.2%。我们的总体假设是疫苗诱导的nAb反应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)利用重组肽库的差异生物annin分离与保护相关的HIV-C Env mimotopes， b)分离特定mimotope/表位的单个b细胞，3)PCR扩增RM免疫球蛋白可变区域，以及4)生成重组抗体。这些新方法已经分离出两种新的嵌合猴/人nmab，具有预测的表位特异性。

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, our recent rhesus macaques (RM) studies showed that recombinant protein immunogens (SIV Gag-Pol particles, HIV Tat, and multimeric HIV clade C (HIV-C) gp160) achieved complete protection in some RMs against multiple challenges with a heterologous clade C SHIV (SHIV-C). Our study simultaneously linked both cellular and humoral immune responses to protection. In all, we have five vaccine-protected RMs that remained free of persistent, systemic infection; all have high-titer neutralizing antibodies (nAbs) induced by multimeric gp160 against SHIV-C encoding env of a different HIV-C strain with 22.2% divergence compared to the gp160 immunogen. Our overall hypothesis is that vaccine-induced nAb responses 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) differential biopannin with recombinant peptide libraries to isolate HIV-C Env mimotopes linked to protection, b) isolation of single 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 tools for the following Specific Aims: 1. to characterize the epitopes recognized by polyclonal Abs of vaccine-protected RMs by subtractive biopanning. First, we will positively select recombinant phages encodin random peptide libraries by biopanning with sera from a protected RM, followed by negative counter-selection with serum from vaccinated, unprotected RM without significant nAb levels. After several rounds of positive/negative selection, recombinant phages will reflect mimotopes linked to protection. 2. to isolate antigen-specific single B cells from the protected RM and PCR amplify the heavy/light chain variable immunoglobulin regions, using our newly generated RM-specific primers that led to the successful isolation of nmAbs with the predicted specificity as well as potent neutralization. 3. to perform passive immunization in humanized chimeric mice with the novel nmAbs to demonstrate protection against mucosal HIV acquisition. These experiments will show that HIV vaccine-induced nAbs (as opposed to nmAbs isolated from chronically infected individuals) have the potential to prevent HIV acquisition. Our studies will also identify the protective epitopes in vivo and provide important information for HIV/AIDS vaccine design and optimization.