目的　探讨CTLA 4对T细胞无能的诱导作用。方法　通过使用超抗原SEA作为一种无能诱导剂 ,建立体外无能模型 ,检测了无能T细胞在受到SEA的再次刺激时其膜分子CD2 8和CTLA 4的表达。结果　与活化T细胞相比 ,无能T细胞在免疫应答的后期阶段表面表达高水平的CTLA 4分子 ,而CD2 8的表达则只较活化组T细胞稍高一些。结论　CTLA 4表面表达水平的升高很可能与T细胞无能状态的诱导有关 Objective To investigate the inducible effect of CTLA 4 on T cells. Methods By using superantigen SEA as an impotence inducer, an in vitro impotence model was established and the expression of membrane molecules CD28 and CTLA 4 of implanted T cells stimulated by SEA was detected. Results Compared with activated T cells, the impaired T cells expressed high levels of CTLA 4 molecules on the surface of the immune response, while the expression of CD28 was only slightly higher than that of activated T cells. Conclusion The elevated expression of CTLA 4 is probably related to the induction of T cell impotence