HIV Envelope gp120-induced immunosuppression

项目概要/摘要 HIV包膜gp 120引起免疫抑制的能力已经在文献中有很好的记载。 文学。这些抑制作用可以由gp 120独立于病毒感染而触发。最近的数据 也证明了通过疫苗载体递送的gp 120对CD 4 T细胞活化的抑制。可是 对于这种抑制活性的分子机制知之甚少。事实上，GP 120的读数- 介导的抑制主要基于标准T细胞应答如增殖， 细胞毒性、细胞因子产生。gp 120对T细胞活化所必需的上游事件的影响 一点都不清楚重要的是要注意，在CD 4和/或趋化因子受体的参与下，gp 120 触发独特的gp 120/CD 4超分子重排和激活信号， T细胞信号机制的组成部分，但如何gp 120触发集群和信号实际上 与生理性T细胞受体介导的活化途径相交并改变生理性T细胞受体介导的活化途径仍然未知。 本申请的目的是研究CD 4 T细胞与gp 120相互作用对CD 4 T细胞增殖的影响。 T细胞活化的早期事件，即免疫突触的形成和随后的信号传导 事件我们的主要假设是gp 120干扰T细胞受体介导的免疫突触 组装和信号传导以引起下游T细胞应答的抑制。为了验证这一假设， 合成的玻璃支撑的平面双层系统将被用于模拟带有 同源T细胞受体配体（肽-MHC复合物或抗-CD 3），共刺激分子，和 gp120。与最先进的荧光显微镜一起，该实验系统使 获得免疫突触及其特定成分的高分辨率动态图像。 因此，我们将采用这种创新的技术来探索gp 120相互作用对两种类型的 CD 4 T细胞，记忆和幼稚，显示不同的免疫突触特征和激活 要求.对于每种细胞类型，我们将评估已知对完整CD 4 T细胞至关重要的四个参数。 活化：a）免疫突触组装、形态和稳定性，B）T细胞受体近端信号 活化，c）立即细胞反应（Ca 2+通量和CD 69上调），和d）下游细胞反应（Ca 2+通量和CD 69上调）。 效应子功能（细胞因子产生和增殖）。 HIV gp 120是抗HIV抗体的重要靶点。因为它已经变得越来越清楚， 抗体反应是艾滋病毒疫苗不可或缺的因素，我们必须更好地了解，不仅 对gp 120的免疫应答以及该抗原的免疫抑制潜力，特别是对CD 4 T细胞的免疫抑制作用， 帮助体液和细胞反应的发展和维持的细胞。数据 从这项研究中产生的将是有价值的设计gp 120为基础的预防和治疗策略， 有效阻止艾滋病毒感染和疾病。

PROJECT SUMMARY/ABSTRACT The capacity of HIV envelope gp120 to cause immune suppression has been well documented in the literatures. These suppressive effects can be triggered by gp120 independent of virus infection. Recent data also demonstrate suppression of CD4 T cell activation by gp120 delivered via vaccine vectors. However, very little is known about the molecular mechanisms for this suppressive activity. In fact, the read-outs for gp120- mediated suppression have been based mainly on the standard T cell responses such as proliferation, cytotoxicity, cytokine production. The effects of gp120 on the upstream events essential for T cell activation are not at all clear. It is important to note that, upon engagement of CD4 and/or chemokine receptors, gp120 triggers unique gp120/CD4 supramolecular rearrangements and activation signals that involve many components of the T cell signaling machinery, but how the gp120-triggered clustering and signaling actually intersect with and alter the physiologic T cell receptor-mediated activation pathway remains unknown. The goal of this application is to investigate the consequences of CD4 T cell interaction with gp120 on the early events in T cell activation, i.e. the formation of immunological synapse and the subsequent signaling events. Our main hypothesis is that gp120 interferes with T cell receptor-mediated immunological synapse assembly and signaling to cause suppression of downstream T cell responses. To test this hypothesis, the synthetic glass-supported planar bilayer system will be utilized to mimic antigen-presenting cells bearing the cognate T cell receptor ligands (peptide-MHC complexes or anti-CD3), the costimulatory molecules, and gp120. Together with the state-of-the-art fluorescence microscopy, this experimental system enables acquisition of high-resolution and dynamic images of immunological synapse and its specific component. Hence, we will employ this innovative technology to explore the effects of gp120 interaction on two types of CD4 T cells, memory and naive, which display different immunological synapse characteristics and activation requirements. For each cell type, we will evaluate four parameters known to be critical for full CD4 T cell activation: a) immunological synapse assembly, morphology, and stability, b) T cell receptor-proximal signal activation, c) the immediate cellular responses (Ca2+ flux and CD69 upregulation), and d) the downstream effector functions (cytokine production and proliferation). HIV gp120 is an important target for anti-HIV antibodies. Since it has become clearer that induction of antibody responses is an indispensable element for HIV vaccines, we must understand better not only the immune responses to gp120 but also the immunosuppressive potential of this antigen, especially on CD4 T cells that provide help for the development and maintenance of both humoral and cellular responses. The data generated from this study will be valuable for designing gp120-based preventive and therapeutic strategies that are effective to block HIV infection and disease.