Activation Defects in T Cells of Aged Mice

描述（由申请人提供）：先前的工作提出了一个与年龄相关的T细胞衰竭模型，其中老年小鼠的T细胞显示出表面糖蛋白模式的改变和细胞骨架依赖性表面糖蛋白重新定位的缺陷。此外，OSGE是一种针对o -连接糖蛋白（包括CD43、CD44和CD45）的蛋白酶，已被证明可以将老年T细胞的功能恢复到与年轻供者的T细胞相似的水平。三个具体目标将分别解决：(1)糖基化改变，(2)细胞骨架缺陷，(3)体内免疫应答修复。Aim 1a将使用一系列特定的凝集素和糖苷酶来确定哪些T细胞表面糖蛋白有助于减少突触形成、钙信号和衰老T细胞中细胞因子的表达。Aim 1b将使用二维电泳和聚糖谱来鉴定T细胞表面糖蛋白，这些糖蛋白对酶消化的敏感性与酶改善T细胞功能的能力相似。Aim 1c使用多重RT-PCR方法开发糖苷和糖基转移酶mrna的年龄相关变化列表。目的1d评估特异性表面糖蛋白（从CD44、CD45、CD4和CDS开始）对功能相关酶的易感性。Aim 2将探索衰老T细胞无法将分子移动到突触或与APC接触部位相反的远端极复合体（DPC）的分子基础。这一目的探讨了两个相关的假设：(a) T细胞激活缺陷涉及无法去除从突触到DPC的抑制分子，包括CD43和蛋白磷酸酶，以及(b)细胞骨架缺陷涉及ERM家族中蛋白质磷酸化的改变。Aim 3将使用两种体内过继转移系统，观察来自老年供体的经酶处理的T细胞对半抗原载体偶联物和可移植肿瘤的反应是否表现出改善的功能。对老年人T细胞功能低下的基础知识的进一步了解，以及接触酶纠正这些缺陷的机制，可能会指出保护老年人免受癌症和感染的新方法，以及改进老年人的疫苗接种方法。

DESCRIPTION (provided by applicant): Prior work has suggested a model for age-related T cell failure in which T cells from aged mice show both altered surface glycoprotein patterns and defects in cytoskeleton-dependent relocalization of surface glycoproteins. In addition, OSGE, a protease specific for O-linked glycoproteins including CD43, CD44, and CD45, has been shown to restore function of aged T cells to levels similar to that of T cells of young donors. Three specific aims will address, respectively, (1) altered glycosylation, (2) cytoskeletal defects, and (3) repair of in vivo immune responses. Aim 1 a will use a battery of specific lectins and glycosidases to determine which T cell surface glycoproteins contribute to diminished synapse formation, calcium signals, and cytokine expression in aged T cells. Aim 1b will use 2D electrophoresis and glycan-profiling to identify the T cell surface glycoproteins whose susceptibility to enzymatic digestion parallels the ability of the enzymes to improve T cell function. Aim 1c uses a multiplex RT-PCR approach to develop a listing of age-related changes in mRNAs for glycosides and glycosyl-transferases. Aim 1 d evaluates specific surface glycoproteins, starting with CD44, CD45, CD4, and CDS, for susceptibility to the functionally relevant enzymes. Aim 2 will explore the molecular basis for the failure of aged T cells to move molecules either into the synapse, or into the distal pole complex (DPC) opposite from the site of APC contact. This aim explores two related hypotheses: (a) that T cell activation defects involve a failure to remove inhibitory molecules, including CD43 and protein phosphatases, from the synapse to the DPC, and (b) that the cytoskeletal defect involves altered phosphorylation of proteins in the ERM family. Aim 3 will use two in vivo adoptive transfer systems to see if enzyme-treated T cells from aged donors show improved function in responses to hapten-carrier conjugates and to transplantable tumors. Improved knowledge of the basis for poor T cell function in old age, and the mechanisms by which enzyme exposure corrects these defects, could point to new ways to protect the elderly from cancer and infection, as well as to improvements in vaccination methods for old people.