HIV GP120 Desensitization of TCell Receptor Function

描述：(申请人提供)进步的一个主要因素 HIV疾病导致艾滋病的主要原因是功能上的CD4+T细胞的丧失 体液和细胞免疫反应的关键辅助活动。它 似乎只有一小部分T细胞丢失可归因于溶血 感染。更确切地说，大多数T细胞被刺激成为抗菌剂无反应 和/或通过HIV gp120诱导的机制进行细胞凋亡 CD4介导的跨膜信号转导。这种反应显然可以是 由可溶性gp120、gpl2诱导(由内源性抗gp 120聚集 抗体、HTV本身或表达细胞表面gp120的感染细胞。这个 CD4“抑制”信号转导的分子机制 未知。在本申请中提出的实验试图解决分子 Gp120刺激的CD4信号的基础和功能后果。 在之前的支持期内进行的研究导致了 我们对激活的抑制信号通路的理解有了飞跃 Gp120。他们表明，含有肌醇5磷酸酶的SH2结构域和 它的效应器，即QF Kiinase(DOK)下游的适配器，以前是 与抑制FcyRIIB信号有关，与CD4fLck相关 并被GP 120在CD4聚集时磷酸化。此外， 结果表明SHIP和DOK的接头功能和酶活性 都被这种刺激所激活。最后，使用T细胞从 Ship基因敲除小鼠证明SI-HP是实现最佳的CD4介导的必要条件 抑制T细胞活化。 为了阐明这一环路，我们提出了分子间的解剖。 CD4/Lck、SHIP和DOK之间的相互作用及其调节功能 互动(目标1)。进一步研究wifi定义TCR信令中的站点 级联是船和船坞的目标(目标2)。在目标3中，我们建议使用 的SCID-Hu Thyfliv模型直接分析了船和Dok在 HIV-1诱导的人T细胞免疫病理。最后，我们将解决 SHIP和DOK在艾滋病毒疾病向艾滋病发展过程中的作用(目标4)。 这些研究将使用生化分析的信号转导，在 结合基因突变和ANC缺失，以及人鼠嵌合体来定义 该途径中的结构-功能关系。最后，艾滋病毒感染者 将被用来评估突变/异型差异的可能性 哪种情况下这种抑制回路不活跃可能会导致长期 无进展。这些研究可能会确认船舶是发现 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.