HIV Envelope gp120-induced immunosuppression

项目摘要/摘要 HIV包膜gp120导致免疫抑制的能力已在 文学作品。这些抑制作用可以由不依赖病毒感染的gp120触发。最新数据 还展示了通过疫苗载体传递的gp120对CD4T细胞激活的抑制作用。然而，非常 人们对这种抑制活性的分子机制知之甚少。事实上，gp120的读数- 介导的抑制主要基于标准的T细胞反应，如增殖， 细胞毒性，细胞因子的产生。Gp120对T细胞活化所必需的上游事件的影响 完全不清楚。值得注意的是，当cd4和/或趋化因子受体结合时，gp120 触发独特的gp120/CD4超分子重排和激活信号，涉及许多 T细胞信号机制的组成部分，但gp120实际上是如何触发集群和信号传递的 与生理T细胞受体介导的激活途径相交和改变仍不清楚。 本应用程序的目的是研究CD4T细胞与gp120相互作用对 T细胞活化的早期事件，即免疫突触的形成和随后的信号转导 事件。我们的主要假设是gp120干扰T细胞受体介导的免疫突触 装配和信号传递导致下游T细胞反应被抑制。为了检验这一假设， 合成玻璃支撑的平面双层系统将被用来模拟携带有 同源T细胞受体配体(肽-MHC复合体或抗CD3)，共刺激分子，以及 Gp120。结合最先进的荧光显微镜，该实验系统能够 获取免疫突触及其特定成分的高分辨率动态图像。 因此，我们将利用这项创新技术来探索gp120相互作用对两种类型的 CD4T细胞、记忆性和幼稚细胞表现出不同的免疫突触特征和激活 要求。对于每种细胞类型，我们将评估四个已知对完整的CD4T细胞至关重要的参数 激活：a)免疫突触组装、形态和稳定性，b)T细胞受体-近端信号 激活，c)细胞的即时反应(钙流通量和CD69上调)，以及d)下游 效应器功能(细胞因子的产生和增殖)。 HIV gp120是抗HIV抗体的重要靶点。因为已经变得更加明显，诱导 抗体反应是HIV疫苗不可或缺的要素，我们不仅要更好地了解 对gp120的免疫反应，以及该抗原的免疫抑制潜力，特别是对CD4T的免疫抑制 为体液和细胞反应的发展和维持提供帮助的细胞。数据 这项研究产生的结果将对设计基于gp120的预防和治疗策略具有价值 对阻止艾滋病毒感染和疾病是有效的。

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.