佛波酯对人外周血淋巴细胞CD3和CD4及CD8分子表达的作用

目的:分析佛波酯(PMA)对细胞表面CD3、CD4和CD8表达的影响,及与胞浆内细胞因子分泌的关系.方法:取10例健康儿童及27例呼吸道感染患儿外周血单个核细胞作体外培养后,用不同浓度及时间PMA刺激后作胞浆内细胞因子及细胞表面分子标记物分析.结果:与未刺激组相比,PMA不同浓度(5、10、20和50 ng/ml)刺激4 h后CD4表达均有明显下降,分别从41.03%、40.18%、42.29%及42.85%下调至28.22%、24.44%、26.09%及25.70%,10 ng/ml浓度刺激4、6 h后细胞表面CD4也有显著下调,分别从45.54%及40.56%下调至28.88%及20.03%,且CD4表达与胞浆内细胞因子分泌呈负相关(r=-0.601,P<0.001).PMA对CD3(刺激前后分别为49.57%及51.54%)及CD8(刺激前后分别为13.02%及12.85%)表达差异无显著性,而在CD3 T淋巴细胞中,CD4-CD8-细胞仅占5.52%.结论:PMA刺激对辅助性T淋巴细胞(Th)表面CD4表达有显著下调作用,且Th细胞胞浆内细胞因子分泌越多,CD4分子下调越明显,而PMA对CD3及CD8无明显下调作用.可采用CD3 CD8-表面标记的方法间接定义Th细胞,替代CD4分子,以避免PMA这种效应对Th1/Th2数量检测所带来的困难.

Regulation of CD3,CD4 and CD8 expressions on PMA-activated human peripheral T cells

Objective: To investigate the effect of mitogen Phorbol 12-myristate 13-Acetate (PMA) on CD3,CD4 and CD8 expression of human T-lymphocytes. Methods: Peripheral blood mononuclear cells from 37 blood samples stimulated in vitro with PMA at different concentrations (2,5,10,20 and 50 ng/ml for 4 hours) and time (10 ng/ml for 2,4 and 6 hours) were analyzed by 4-color flow cytometry (FCM). Results: Under different PMA stimulation protocols,significant CD4 down-regulation was observed,which was negatively correlated with intracellular cytokine secretion (r=-0.601,P<0.001),except for PMA stimulation at 10 ng/ml for 2-hours which showed no significant intracellular cytokine secretion. The expressions of CD3 and CD8 molecules after PMA activation were not significantly affected as compared with pre-activation. Among CD3 positive T-lymphocytes, CD4/CD8 double-negative cells only account for 5.52%. Conclusion: PMA has a significant down-regulation effect on CD4 molecules of Th cells,without altering the CD3 and CD8 expression. For quantitative analysis of Th1/Th2 variation,indirect method such as CD3 CD8- T cells can be used to define CD4 Th cells stimulated by PMA in the future.