Activation Defects in T Cells of Aged Mice

描述(申请人提供)：先前的工作提出了一种与年龄相关的T细胞衰竭模型，在该模型中，来自老龄小鼠的T细胞既显示了表面糖蛋白模式的改变，又显示了表面糖蛋白依赖于细胞骨架的重新定位的缺陷。此外，OSGE是一种针对包括CD43、CD44和CD45在内的O-连接糖蛋白的蛋白酶，已被证明可以将老年T细胞的功能恢复到与年轻捐赠者的T细胞相似的水平。三个特定的目标将分别涉及(1)糖基化改变，(2)细胞骨架缺陷，和(3)体内免疫反应的修复。目标1a将使用一组特定的凝集素和糖苷酶来确定哪些T细胞表面糖蛋白与衰老T细胞突触形成、钙信号和细胞因子表达减少有关。目的1b将使用2D电泳法和糖谱分析来鉴定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细胞功能的能力平行。AIM 1c使用多重RT-PCR方法来开发与年龄相关的糖苷和糖基转移酶mRNAs的变化清单。目的评价从CD44、CD45、CD4和CDS开始的特定表面糖蛋白对功能相关酶的敏感性。目的2将探索衰老T细胞不能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。这一目标探索了两个相关的假设：(A)T细胞激活缺陷涉及未能将包括CD43和蛋白磷酸酶在内的抑制分子从突触移至DPC，以及(B)细胞骨架缺陷涉及ERM家族蛋白质的磷酸化改变。Aim 3将使用两种体内过继转移系统来观察来自老年捐赠者的酶处理的T细胞在半抗原-载体结合物和可移植肿瘤的反应中是否表现出更好的功能。更好地了解老年人T细胞功能低下的基础，以及酶暴露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，以及改善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.