Project 1-Mechanism of Anti-Gp120 Antibody Persistence

项目摘要/摘要 最近的临床试验和大量非人类灵长类动物的研究将艾滋病毒疫苗领域进一步推向 基于体液抗HIV包膜免疫的概念的发展。然而，这种努力面临着一个重大的 障碍在于，对HIV包膜抗原的常规短暂体液反应将严重损害 艾滋病毒疫苗的效力。另外需要注意的是，任何解决体液持续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HIV的CD4+T细胞激活形式 感染风险。最近对痘病毒/包膜蛋白方案的RV144临床试验强调了这一问题 人类。在这项试验中，抗gp120抗体反应，包括那些与部分疗效有关的反应，衰退到 12个月内检测不到的水平。根据现有文献，我们假设抗gp120滴度 以这种方式迅速消退是因为1)HIV gp120特异的浆细胞在生发过程中被广泛杀死 中心反应或2)HIV gp120特异性浆细胞在生发中心反应中存活，但不能移动到 骨髓变成长寿细胞。从理论上讲，这些问题可以通过比较 对产生持久抗体效价的疫苗方案与不产生持久抗体效价的疫苗方案进行分析。这一战略已经 由于缺乏可靠地产生持久的抗gp120体液反应的方案而受到阻碍。我们的团队 已在多种佐剂配方和疫苗接种方案中测试了相同的gp120抗原 在猕猴身上。最近，我们确定了其中一种方案，即用包膜联合免疫 佐剂中的蛋白质以及编码IL-12的DNA(这里称为DNA/蛋白质)的电穿孔 联合免疫)，与任何其他方法相比，产生的持久抗体滴度显著更高 测试过。这些发现现在为进行比较研究提供了必要的手段，以阐明 持续的抗gp120抗体反应的决定因素。因此，本项目将与 DNA/蛋白质联合免疫方案与匹配的蛋白质/佐剂方案产生非持久性 回应。我们建议的比较分析将由上面列出的两个假设驱动。在两个具体的 目标，我们将解决持续的抗HIV抗体反应是否通过1)保存 在没有骨髓中长寿命浆细胞增强的情况下短期抗gp120浆母细胞 2)在骨髓中建立长寿的抗gp120浆细胞。我们还将利用 DNA/蛋白质共免疫的多方面性质，以识别疫苗成分和相关 提供持久的体液抗gp120反应的免疫途径，理想的CD4+T细胞分布和 对异源新城疫病毒攻击的保护作用。来自该项目的信息应该具有重要的意义 影响，为疫苗方案的开发提供广泛适用的、基于免疫的基础 提供持久的抗包膜抗体反应。

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.