HIV GP120 Desensitization of TCell Receptor Function

HIV GP120 T细胞受体功能脱敏

基本信息

批准号：
6599249
负责人：
John C Cambier
金额：
$ 14.96万
依托单位：
UNIVERSITY OF COLORADO DENVER
依托单位国家：
美国
项目类别：
财政年份：
1995
资助国家：
美国
起止时间：
1995-06-01 至 2002-09-29
项目状态：
已结题

项目摘要

DESCRIPTION: (provided by applicant) A major contributing factor in progression of HIV disease to AIDS is the loss of functional CD4+ T cells that provide critical helper activity for humoral and cell-mediated immune responses. It appears that only a small, proportion of T cell loss is attributable to lytic infection. Rather most T cells are stimulated to become antiger irresponsive and/or to undergo apoptosis by a mechanism involving of HIV gp120-induced CD4-mediatec transmembrane signal transduction. This response can apparently be induced by soluble gp120, gpl2( aggregated by endogenous anti-gp 120 antibodies, HTV itself or infected cells expressing cell surface gp120. The molecular mechanisms underlying CD4 transduction of "inhibitory" signals is unknown. Experiments proposed in this application seek to address the molecular basis and functional consequences of gp120 stimulated CD4 signaling. Studies conducted during the previous period of support have led to a quantum leap in our understanding of the inhibitory signaling circuitry activated by gp120. They show that the SH2 domain containing jnositol 5 Phosphatase SHIP and its effector, the adapter Downstream Qf Kiinase (Dok), which were previously implicate in inhibitory FcyRIIB signaling, are associated with CD4fLck complexes and are phosphorylated upon CD4 aggregation by gp 120. Further, findings indicate that linker functions of SHIP and Dok, and enzymatic activity of SHIP are activated by this stimulation. Finally, studies using T cells from SHIP knockout mice demonstrate that SI-HP is required for optimal CD4-mediated inhibition of T cell activation. Towards elucidation of this circuitiy, we propose dissection of intermolecular interactions among CD4/Lck, SHIP and Dok, and the regulatory function of these interactions (aim 1). Further studies wifi define the site within TCR signaling cascades that are the targets of SHIP and Dok (aim 2). In aim 3 we propose use of the SCID-hu thyfliv model to directly analyze the role of SHIP and Dok in HIV- 1 induced immunopathology ir human T cells. Finally, we will address the role of SHIP and Dok in progression of HIV disease to AIDS (aim 4). The studies will employ biochemical assays of signal transduction, in conjunction with gene mutation anc deletion, and human-mouse chimera to define structure-function relationships in the pathway. Finally, HIV infected patients will be employed to assess the possibility that mutations/allotypic differences which rendei this inhibitory circuit inactive may result in long term non-progression. The studies may validate SHIP as target for discovery of therapeutic agents for AIDS.

描述：（由申请人提供）进步的主要影响因素 HIV 疾病发展为 AIDS 的原因在于功能性 CD4+ T 细胞的丧失，这些细胞提供体液和细胞介导的免疫反应的关键辅助活性。它似乎只有一小部分 T 细胞损失可归因于裂解感染。相反，大多数 T 细胞受到刺激而变得对抗原无反应和/或通过涉及HIV gp120诱导的机制经历细胞凋亡 CD4-mediatec 跨膜信号转导。这个回应显然可以由可溶性 gp120、gpl2（由内源性抗 gp 120 聚集）诱导抗体、HIV 本身或表达细胞表面 gp120 的感染细胞。这 CD4“抑制”信号转导的分子机制是未知。本申请中提出的实验旨在解决分子 gp120 刺激 CD4 信号传导的基础和功能后果。在上一个支持期间进行的研究已经产生了量子我们对抑制信号通路激活的理解取得了飞跃 GP120。他们表明 SH2 结构域含有肌醇 5 磷酸酶 SHIP 和它的效应器，适配器下游 Qf Kiinase (Dok)，以前是参与抑制性 FcyRIIB 信号传导，与 CD4fLck 相关复合物并在 CD4 聚集时被 gp 120 磷酸化。此外，研究结果表明 SHIP 和 Dok 的连接子功能以及酶活性 SHIP 被这种刺激激活。最后，研究使用来自 SHIP 敲除小鼠证明 SI-HP 是最佳 CD4 介导所必需的抑制T细胞活化。为了阐明这个电路，我们建议解剖分子间 CD4/Lck、SHIP 和 Dok 之间的相互作用以及它们的调节功能互动（目标 1）。进一步研究 wifi 定义了 TCR 信令中的站点级联是 SHIP 和 Dok 的目标（目标 2）。在目标 3 中，我们建议使用 SCID-hu thyfliv 模型直接分析 SHIP 和 Dok 在 HIV-1 诱导人类 T 细胞的免疫病理学。最后，我们将解决 SHIP 和 Dok 在 HIV 疾病进展为 AIDS 中的作用（目标 4）。这些研究将采用信号转导的生化测定，结合基因突变和缺失以及人鼠嵌合体来定义通路中的结构-功能关系。最后，艾滋病病毒感染者将用于评估突变/同种异型差异的可能性哪个rendei这个抑制电路不活跃可能会导致长期不进展。这些研究可能会验证 SHIP 作为发现的目标艾滋病治疗剂。