Fas/Fas L在超抗原 SEA诱导 T细胞凋亡中的作用(英文)

The effect of Fas/FasL on T cell apoptosis induced by staphylococcal enterotoxin A(SEA)

目的超抗原能诱导 T细胞凋亡 ,但其作用机制尚未阐明 ,Fas系统与 Ca2 +在其中的作用尚待进一步研究。方法超抗原金黄色葡萄球菌肠毒素 A(SEA)诱导人外周血建立的短期 SEA反应 T细胞系凋亡 ,1.8%琼脂糖凝胶 DNA电泳于不同时间观察凋亡的特征条带 ;FCM检测 Fas、Fas L 的表达量变化 ,Fura- 2 / AM荧光指示剂检测胞浆游离 [Ca2 + ]i的变化。结果使用 FCM特异性检测凋亡亚 G0 / G1峰大小及 1.8%琼脂糖凝胶电泳检测凋亡 DNA梯状图谱证明 ,SEA能诱导短期 SEA反应 T细胞凋亡 ,其凋亡的时间与程度与 SEA的剂量有关。SEA1μg/ ml建立的短期 SEA反应 T细胞对 SEA1μg/ml的再次刺激 ,凋亡量随作用时间的延长而增多 ,在作用的第 16 h最高 ,达 5 8%。 FCM间接荧光染色法检测发现 ,Fas及Fas L 亦随 SEA作用时间的延长而表达增多 ,16 h时表达最多 ,分别为 92 %和 6 0 %。用 Fura- 2 / AM荧光指示剂检测 ,此时细胞胞浆 [Ca2 + ]i已从刺激前的 (2 90± 33) nm ol/ L 上升到 (6 80± 16 ) nmol/ L。结论 Fas系统与 SEA诱导的 T细胞凋亡密切相关。换言之 ,Fas系统在超抗原诱导 T细胞凋亡中起作用 ,而胞浆 [Ca2 + ]i升高与 SEA诱导的凋亡 T细胞 DNA断裂及其它凋亡形态变化有关。

Objective[WT5”BZ]To investigate the effect of Fas/Fas ligand (FasL) interactions on the superantigen induced apoptosis of human peripheral T cell. Methods Apoptosis of SEA reactive T cell line, established from human peripheral blood mononuclear cells (PBMC), was induced by SEA. The features of apoptosis were observed with light microscope, flow cytometry (FCM) and DNA electrophoresis ladder. The Fas/FasL changes and cytosolic Ca 2+ concentration were measured with FCM and fluorescent probe Fura 2/AM during the T cell apoptosis. Results A short term SEA reactive T cell line was established by stimulating PBMC 10 6 with 1 μg/ml SEA for 3 days and expanding the cells in rIL 2 (200 U/ml). These cells were maintained in rIL 2 for 2 weeks before use. Both FCM and DNA electrophoresis ladder could demonstrate that apoptosis appeared obviously by second stimulation of the SEA reactive T cells with SEA 1 μg/ml. Fas/FasL was substantially upregulated with an increase of cytosolic free Ca 2+ . Conclusion These findings suggest that Fas/FasL plays an important role in the superantigen induced T cell apoptosis and the increase of cytosolic Ca 2+ was related to DNA fragmentation and morphological changes of T cell apoptosis. [