CD28协同刺激分子对T细胞受体介导的胸腺细胞亚群凋亡的影响

Effect of CD28 costimulator on T Cell receptor (TCR) -induced apoptosis of thymocytes

目的:分析anti-TCRαβ mAb、anti-TCRαβ mAb+anti-CD28mAb诱导小鼠胸腺淋巴细胞不同亚群的凋亡及凋亡程度,分析CD28协同刺激分子对TCR受体介导的胸腺细胞亚群凋亡 的影响。方法:新鲜分离胸腺细胞,加入anti-TCRαβ mAb、anti-TCRαβ mAb+anti-CD28 mAb等培养20 h,进行多重染色,流式细胞仪分析。结果:与胸腺细胞自发凋亡的结果相比较:①双信号刺激可明显增加胸腺细胞凋亡的数目,尤其是CD4+ CD8+胸腺细胞的凋亡数目。②凋亡的CD4+ CD8+亚群、CD4+ CD8-亚群细胞表面CD28的表达均增多。结论:CD28共刺激分子对TCR受体介导的胸腺细胞亚群凋亡的影响与细胞的成熟程度有关。CD28共刺激分子能明显增强不成熟皮质胸腺细胞的凋亡。

AIM: To analyze apoptosis and its degree of thymocytes at early and intermediate phases induced by anti-TCRαβ mAb or anti-TCRαβ mAb + anti-CD28 mAb stimuli, and to analyze the influence of CD28 costimulator on TCR-induced apoptosis of thymocyte subsets. METHODS; Thymocytes were freshly prepared and were cultured for 20 h in the presence of anti-TCRαβ mAb + anti-CD28 mAb or anti-TCRαβ mAb along, The cultured cells were stained with fluorescein labelled Annexin V, PI, anti-CD4 mAb and anti-CD8 mAb, then color reagents. The apoptotic cells were analyzed by FACS. RESULTS; Compared with the spontaneous apoptosis of thymocytes cultured in medium alone, CD28 costimulator markedly enhanced the number of thymocyte apoptosis at early and intermediate phases; under the action of double signaling stimulators, the apoptosis of CD4+ CD8+ (DP) thumocytes were substantially increased, and the expression of CD28 were also upregulated on these apoptotic DP cells. CONCLUSION; Influence of CD28 costimulator on TCR- induced apoptosis of thymocyte subsets might be related to thymocyte' s mature degree. Double signaling may induce apoptosis of DP thymocytes.