Project 1-Mechanism of Anti-Gp120 Antibody Persistence

项目概要/摘要 最近的临床试验和许多非人类灵长类动物研究将HIV疫苗领域进一步推向了 发展基于体液抗HIV包膜免疫的概念。然而，这种努力面临着一个重大的挑战。 障碍在于，对HIV包膜抗原的常规短暂体液应答将严重损害 HIV疫苗的功效另一个警告是，任何解决体液持久性问题的方法都必须包括 平衡的免疫反应，不会产生可能增加艾滋病毒感染的CD 4 + T细胞活化形式 感染风险。最近的RV 144痘病毒/包膜蛋白方案的临床试验强调了 人类在这项试验中，抗gp 120抗体应答，包括与部分疗效相关的应答， 在12个月内达到无法检测的水平。基于现有文献，我们假设抗gp 120滴度 以这种方式迅速消退，因为1）HIV gp 120特异性浆细胞在生殖过程中被广泛杀死 中心反应或2）HIV gp 120特异性浆细胞在生殖中心反应中存活，但不能进入 使骨髓成为长寿的细胞。从理论上讲，这些问题可以通过比较 分析产生持续抗体滴度的疫苗方案与不产生持续抗体滴度的疫苗方案。这一战略 由于缺乏可靠地产生持续抗GP 120体液应答的方案而受到阻碍。我们集团 已经在多种佐剂制剂和疫苗接种方案中测试了相同的基于gp 120的抗原 在猕猴身上。最近，我们确定其中一种方案，涉及与包膜蛋白共免疫， 沿着电穿孔编码IL-12的DNA（本文称为DNA/蛋白质 共免疫），产生显着更持久的抗体滴度相比，任何其他方法，我们 测试.这些发现现在提供了进行比较研究以阐明 持续抗-GP 120抗体应答的决定因素。因此，本项目将与 DNA/蛋白质共免疫方案与匹配的蛋白质/佐剂方案， 应答我们提出的比较分析将由上面列出的两个假设驱动。在两个具体 目的，我们将解决是否持续抗HIV抗体反应的区别1）保存 短期抗gp 120浆母细胞，而骨髓中的长寿命浆细胞没有增强 或2）在骨髓中建立长寿命的抗GP 120浆细胞。我们还将利用 DNA/蛋白质共免疫的多面性，以鉴定疫苗组分和相关的 免疫途径提供持续的体液抗gp 120应答、期望的CD 4 + T细胞谱和 对异源SHIV攻击的保护效力。该项目的信息应具有重要意义 影响，为疫苗方案的开发提供广泛适用的免疫基础 其提供持续的抗包膜抗体应答。

Project Summary/Abstract Recent clinical trials and a host of nonhuman primate studies have pushed the HIV vaccine field further toward the development of concepts based on humoral anti-HIV envelope immunity. However, such efforts face a major hurdle in that the routinely short-lived humoral responses to HIV envelope antigens will severely compromise HIV vaccine efficacy. An additional caveat is that any solution to the humoral persistence problem must include balanced immune responses that do not engender forms of CD4+ T cell activation that might increase HIV infection risk. The recent RV144 clinical trial of a poxvirus/ envelope protein regimen underscores the issue in humans. In this trial, anti-gp120 antibody responses, including those linked with partial efficacy, decayed to undetectable levels within 12 months. Based on the available literature, we hypothesize that anti-gp120 titers rapidly fade in this manner because 1) HIV gp120-specific plasma cells are extensively killed during the germinal center reaction or 2) HIV gp120-specific plasma cells survive the germinal center reaction but cannot move into the bone marrow to become long-lived cells. Theoretically, these questions can be addressed by comparative analyses of vaccine regimens that yield persistent antibody titers versus ones that do not. This strategy has been hampered by a paucity of regimens that reliably yield persistent anti-gp120 humoral responses. Our group has tested the same gp120-based antigen in a wide variety of adjuvant formulations and vaccination regimens in macaques. Recently we determined that one of these regimens, which involves coimmunizing with envelope protein in adjuvant along with electroporation of DNA encoding IL-12 (herein termed DNA/protein coimmunization), generates significantly more persistent antibody titers compared to any other approach we tested. These findings now provide the necessary means to conduct comparative studies that elucidate the determinants for persistent anti-gp120 antibody responses. Accordingly, this Project will juxtapose the DNA/protein coimmunization regimen with a matched protein/adjuvant regimen that yields non-persistent responses. Our proposed comparative analyses will be driven by the two hypotheses listed above. In two specific aims, we will address whether persistent anti-HIV antibody responses are distinguished by 1) the preservation of short-term anti-gp120 plasmablasts without the enhancement of long-lived plasma cells in the bone marrow or 2) the establishment of long-lived anti-gp120 plasma cells in the bone marrow. We will also exploit the multifaceted nature of DNA/protein coimmunization to Identify vaccine components and associated immunological pathways that afford persistent humoral anti-gp120 responses, desirable CD4+ T cell profiles and protective efficacy against heterologous SHIV challenge. Information from this project should have significant impact, providing broadly applicable, immune-based underpinnings for the development of vaccine regimens that provide persistent anti-envelope antibody responses.