Zhang J, Salojin K, Gao J X, Cameron M, Geisler C, Delovitch T L
Autoimmunity/Diabetes Group, The John P. Robarts Research Institute, University of Western Ontario, London, Canada.
J Immunol. 1998 Sep 15;161(6):2930-7.
The TCR is a multisubunit complex composed of the clonotypic alpha/beta disulfide-linked heterodimer and noncovalently linked invariant CD3 gamma epsilon and CD3 delta epsilon and TCR zeta chains. Recent studies demonstrate that the surface expression of CD3 components can occur independently of the clonotypic TCR complexes in both thymocytes and splenic T cells. In this study, we report that free noncovalently associated TCR alpha beta heterodimers that exist independently of CD3 and TCR zeta chains are expressed on the cell surface of immature thymocytes and peripheral T cells, but not of T cell lines and T cell hybridomas. This suggests that the regulation of surface expression of TCR alpha beta heterodimers differs between primary T cells and T cell lines or T cell hybridomas. The isolation and biochemical characterization of surface clonotype-independent CD3 complexes and free membrane-associated TCR alpha beta complexes may provide a structural basis for the quantitative difference in amount of T cell proliferation stimulated by anti-CD3 epsilon and anti-TCR beta.
TCR是一种多亚基复合体，由克隆型α/β二硫键连接的异二聚体以及非共价连接的恒定CD3γε、CD3δε和TCRζ链组成。最近的研究表明，在胸腺细胞和脾T细胞中，CD3组分的表面表达可以独立于克隆型TCR复合体而发生。在本研究中，我们报告称，游离的非共价结合的TCRαβ异二聚体独立于CD3和TCRζ链而存在，它们在未成熟胸腺细胞和外周T细胞的细胞表面表达，但在T细胞系和T细胞杂交瘤中不表达。这表明，TCRαβ异二聚体表面表达的调控在原代T细胞与T细胞系或T细胞杂交瘤之间存在差异。表面克隆型非依赖性CD3复合体和游离膜相关TCRαβ复合体的分离及生化特性分析，可能为抗CD3ε和抗TCRβ刺激的T细胞增殖量的定量差异提供结构基础。
