Self-Specific MHC Class II-Restricted CD4−CD8− T Cells That Escape Deletion and Lack Regulatory Activity

摘要: In the presence of I-Eα protein, transgenic (Tg) mice expressing 1H3.1 αβ TCR that is specific for Eα52–68:I-Ab complex display drastic intrathymic deletion. Although peripheral T cells from these remained unresponsive to complex, they contained a subpopulation able specifically react this in exogenous IL-2, indicating some Tg have escaped clonal deletion and efficiently populated periphery. IL-2-dependent, complex-responsive were CD4−CD8− expressed TCR. Such could develop intrathymically, did not show sign regulatory/suppressor activity, displayed typical naive phenotype, seemed persist vivo over time. also detected when surface density deleting ligand was increased on MHC class II+ cells. addition, development be supported by I-Ab molecules. These observations indicate CD4 expression neither specifies, nor required for, thymic export mature thymocytes II-restricted The data that, although avidity interaction involved significantly lower than cell activation, its range can large enough influenced or absence coreceptors. Finally, margin created coreceptor substantial because it accommodate various amounts stromal