HIV GP120 Desensitization of TCell Receptor Function

描述：（由申请人提供）进展的主要促成因素 艾滋病的主要原因是功能性CD 4 + T细胞的丧失， 体液和细胞介导的免疫应答的关键辅助活性。它 似乎只有一小部分T细胞损失是由于溶解性T细胞减少， 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 gp 120诱导的机制经历细胞凋亡 CD 4介导的跨膜信号转导。这种反应显然可以 由可溶性gp 120、gp 12（由内源性抗gp 120聚集）诱导 抗体、HIV本身或表达细胞表面gp 120的感染细胞。的 CD 4转导“抑制性”信号的分子机制是 未知在本申请中提出的实验试图解决分子生物学问题。 gp 120刺激的CD 4信号传导的基础和功能后果。 在前一个支助期间进行的研究导致了一个量子 我们对抑制性信号通路的理解有了飞跃， gp120。他们表明含有SH 2结构域的肌醇5磷酸酶SHIP和 其效应子，衔接子下游Qf Kiinase（Dok），其先前被 涉及抑制性Fc γ RIIB信号传导，与CD 4fLck相关 复合物，并在CD 4聚集时被gp 120磷酸化。此外，本发明还 研究结果表明，SHIP和Dok的连接功能，以及酶活性， 的细胞被这种刺激所激活。最后，使用T细胞的研究 SHIP基因敲除小鼠证明SI-HP是最佳的CD 4介导的 抑制T细胞活化。 为了阐明这种电路，我们提出了分子间的解剖， CD 4/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）。进一步的研究确定了TCR信号传导中的位点 作为SHIP和Dok目标的级联（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在人T细胞中诱导的免疫病理学。最后，我们将讨论 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物化学测定， 结合基因突变和缺失，以及人-鼠嵌合体来定义 结构与功能的关系。最后，艾滋病病毒感染者 将用于评估突变/同种异型差异 这使这种抑制回路失活，可能导致长期的 不进步。这些研究可能会验证SHIP作为发现 用于艾滋病的治疗剂。

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.