口服卡介菌诱导免疫耐受的CD4+CD25+调节性T 细胞机制研究

目的:研究口服卡介菌诱导免疫耐受对CD4+CD25+调节性T细胞的影响。方法:采用口服MPB制备EAE大鼠模型,随机分为BCG组(0.5mg/kg)和EAE模型组(PBS),每组各15只,连续经口灌服给药14d,同时选取15只健康大鼠作为对照组。分别于免疫后15d、27d流式细胞术检测外周血、胸腺及脾脏中CD4+CD25+T淋巴细胞百分率,ELISA检测血清IL-6、TGF-β、IgE、IgG含量。结果:与EAE模型组相比,免疫后BCG组大鼠外周血、胸腺及脾脏中CD4+CD25+T淋巴细胞百分率增加,血清IL-6、TGF-β含量上升,血清IgE、IgG抗体水平下降。结论:口服BCG通过上调淋巴器官中CD4+CD25+T淋巴细胞比例,抑制效应性T细胞活性,发挥免疫耐受作用。

Studies on CD4+CD25+ T Regulatory Cells in Immune Tolerance Induced by Oral BCG*

Objective: To investigate the influence of oral BCG on CD4+ CD25+ T regulatory cells in inducing immune tolerance.Methods: The EAE rats,induced by immunization with oral MBP,were randomly divided into BCG group(0.5mg/kg) and EAE group(PBS),with 15 rats per group,and 15 normal rats were used as control group.On 15d and 27d after treatment,CD4+ CD25+ T regulatory cells from peripheral blood,thymus and spleen were respectively determined by flow cytometry,and levels of serum IL-6,TGF-β,IgE and IgG were measured by ELISA.Results: Compared with EAE group,CD4+ CD25+ T regulatory cells from peripheral blood,thymus and spleen,and levels of IL-6 and TGF-β increased in BCG group after treatment,but serum IgE and IgG levels decreased.Conclusion: Oral BCG could induce immune tolerance by up-regulating the percentage of CD4+ CD25+ T regulatory cells,inhibiting effector T cell function.