口服卡介菌诱导免疫耐受的CD4^+CD25^+调节性T细胞机制研究

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

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。

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.