Garcia G G, Miller R A
Department of Pathology, University of Michigan School of Medicine, Ann Arbor, MI 48109, USA.
J Immunol. 2001 Mar 1;166(5):3151-7. doi: 10.4049/jimmunol.166.5.3151.
Confocal fluorescent microscopy was used to study redistribution of membrane-associated proteins in naive T cells from young and old mice from a transgenic stock whose T cells express a TCR specific for a peptide derived from pigeon cytochrome C. About 50% of the T cells from young mice that formed conjugates with peptide-pulsed APC were found to form complexes, at the site of binding to the APC, containing CD3epsilon, linker for activation of T cells (LAT), and Zap-70 in a central area and c-Cbl, p95(vav), Grb-2, PLC gamma, Fyn, and Lck distributed more uniformly across the interface area. Two-color staining showed that those cells that were able to relocalize c-Cbl, LAT, CD3epsilon, or PLC gamma typically relocalized all four of these components of the activation complex. About 75% of conjugates that rearranged LAT, c-Cbl, or PLC gamma also exhibited cytoplasmic NF-AT migration to the T cell nucleus. Aging had two effects. First, it led to a diminution of approximately 2-fold in the proportion of T cell/APC conjugates that could relocalize any of the nine tested proteins to the immune synapse. Second, aging diminished by approximately 2-fold the frequency of cytoplasmic NF-AT migration among cells that could generate immune synapses containing LAT, c-Cbl, or PLC gamma. Thus naive CD4 T cells from old mice exhibit at least two separable defects in the earliest stages of activation induced by peptide/MHC complexes.
共聚焦荧光显微镜用于研究来自转基因品系年轻和老年小鼠的初始T细胞中膜相关蛋白的重新分布，该品系的T细胞表达对源自鸽细胞色素C的肽具有特异性的TCR。发现与肽脉冲APC形成结合物的年轻小鼠中约50%的T细胞在与APC结合的部位形成复合物，在中心区域含有CD3ε、T细胞激活连接蛋白（LAT）和Zap-70，而c-Cbl、p95(vav)、Grb-2、PLCγ、Fyn和Lck更均匀地分布在界面区域。双色染色显示，那些能够重新定位c-Cbl、LAT、CD3ε或PLCγ的细胞通常会重新定位激活复合物的所有这四个组分。约75%重新排列LAT、c-Cbl或PLCγ的结合物也表现出细胞质NF-AT向T细胞核的迁移。衰老有两个影响。首先，它导致能够将九种测试蛋白中的任何一种重新定位到免疫突触的T细胞/APC结合物的比例降低约2倍。其次，衰老使能够产生含有LAT、c-Cbl或PLCγ的免疫突触的细胞中细胞质NF-AT迁移的频率降低约2倍。因此，老年小鼠的初始CD4 T细胞在肽/MHC复合物诱导的激活的最早阶段表现出至少两个可分离的缺陷。
