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

目的：分析anti-TCRαβmAb 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-TCRαβmAb-anti-TCRαβmAb anti-CD28mAb等培养20h，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。

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

AIM: To analyze apoptosis and its degree of thymocytes at early and intermediate phases induced by anti-TCRalphabeta mAb or anti-TCRalphabeta 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-TCRalphabeta mAb+anti-CD28 mAb or anti-TCRalphabeta 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) thymocytes 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.