Valk Elke, Rudd Christopher E, Schneider Helga
Cell Signalling Section, Department of Pathology, University of Cambridge, Cambridge CB2 1QP, UK.
Trends Immunol. 2008 Jun;29(6):272-9. doi: 10.1016/j.it.2008.02.011. Epub 2008 May 9.
The T-cell co-receptor cytotoxic T-cell antigen 4 (CTLA-4) has a strong inhibitory role as shown by the lymphoproliferative phenotype of CTLA-4-deficient mice. Despite its potent effects on T-cell function, CTLA-4 is primarily an intracellular antigen whose surface expression is tightly regulated by restricted trafficking to the cell surface and rapid internalisation. Recently, several signalling molecules such as Trim, PLD, ARF-1 and TIRC7 have been described to be involved in the transport of CTLA-4 to the cell surface. Minor changes in surface expression levels have major effects on the outcome of T-cell activation. Optimal regulation of CTLA-4 surface expression is crucial for the balance of stimulatory and inhibitory signals to maximize protective immune responses while maintaining immunological tolerance and preventing autoimmunity.
T细胞共受体细胞毒性T细胞抗原4（CTLA-4）具有很强的抑制作用，CTLA-4缺陷小鼠的淋巴细胞增殖表型就表明了这一点。尽管CTLA-4对T细胞功能有强大作用，但其主要是一种细胞内抗原，其表面表达通过限制转运至细胞表面和快速内化而受到严格调控。最近，已描述了几种信号分子，如TRIM、PLD、ARF-1和TIRC7参与CTLA-4向细胞表面的转运。表面表达水平的微小变化对T细胞活化的结果有重大影响。CTLA-4表面表达的最佳调节对于刺激和抑制信号的平衡至关重要，以在维持免疫耐受和预防自身免疫的同时最大化保护性免疫反应。
