胃癌患者外周血CD4^+CD25^+调节性T细胞的免疫抑制调节

Immunosuppressing function of CD4^+CD25^+ regulatory T cells in peripheral blood of gastric cancer patients

目的:研究胃癌患者外周血中CD4+CD25+T细胞(Treg细胞)对免疫效应细胞以及树突状抗原提呈细胞的抑制调节作用.方法:应用流式细胞术(FACS)测定实验组和对照组患者术前外周血中T淋巴细胞及Treg细胞含量的改变;对外周血中树突状细胞(DC细胞)进行体外培养活化,检测其表面分子CD80和CD83的表达情况;实验组利用免疫磁珠法在培养前去除Treg细胞,以胃癌BGC-823细胞作为靶细胞,效靶比=20∶1,应用CCK-8试剂盒观察不同实验组激活的CTL的细胞毒杀伤反应的差异.结果:诱导辅助性T细胞(CD4+T)总数较健康对照组降低(t=2.847,P<0.01),Treg细胞含量高于健康对照组(t=7.431,P<0.01);表面分子CD80和CD83在胃癌患者外周血DC表面表达较对照组下降(t=16.90,21.43,P<0.01);实验组CTL对胃癌细胞杀伤效率高于对照组(t=2.98,P<0.01).结论:Treg细胞对抑制荷瘤机体内自身抗肿瘤反应有密切关系.

AIM： To investigate the levels of special CD4＋ CD25 ＋ T ceils （Treg） in peripheral blood of the patients with gastric cancer, and to explore the suppressing function of Treg regulatory T cells on effector T cells and dendritic ceils in adoptive immunotherapy of gastric carcinoma. METHODS： By flow cytometry, the levels of CD3＋T cells, CD8＋ T cells, and Treg in peripheral blood of preoperative patients with gastric cancer were detected respectively, and the results were analyzed statistically in comparison with those of the healthy volunteers. Dendritic cells were separated from the peripheral blood of gastric cancer patients and volunteers to be cuhured and activated in vitro. Expressions of CD80 and CD83 on：surface of the mature dendritic cells were detected by flow cytometry. The immunocytes were separated from the peripheral blood of gastric cancer patients to be cultured and activated in vitro. Cytotoxie T-lymphocytes activity against gastric cancer cell line named BGC-823 was measured by CCK-8 Kit, and the effector-to-target ratio was 20：1. RESULTS： The level of induced helper T cells （ CD4 ＋ T） in patients with gastric cancer was lower than that of volunteers （t =2. 847 ,P 〈0.01 ） , and the percentage of Treg in total CD4 ＋ T cells in patients with gastric cancer was increased significantly as compared with that in volunteers （ t = 7.431 ,P 〈 0.01 ） . The expressions of CD80 and CD83 were significantly lower on surface of the mature dendritic cells of gastric cancer patients than those of control group （t = 16.90, 21.43 ,P 〈0.01 ）. The specific cytotoxicity of experiment group which removed Treg from peripheral blood mononuclear cells （PBMCs） was significantly stronger than that in control group which did not remove Treg from PBMCs （t = 2.98,P 〈 0.01 ） . CONCLUSION ： Significantly increased level of Treg cells in peripheral blood of the patients with gastric cancer indicates that Treg cells might play a pivotal role in regulating T cell response in the process of anti-tumor immunity of the gastric cancer patients.