TGF-β1诱导CD4^+CD25^-T细胞分化为CD4^+CD25^+调节性T细胞

TGF-β1 induces differentiation of CD4^+CD25^-T cells into CD4^+CD25^+ reg ulatory T cells

目的研究TGF-β1诱导CD4+CD25+调节性T细胞分化的能力及其相关机理。方法①利用丝裂霉素处理的Balb/C裸鼠脾细胞(同种抗原)刺激C57BL/6小鼠T细胞,同时给予TGF-β1予以干预(按TGF-β1剂量不同设立4组:对照组,低浓度组,中浓度组和高浓度组),共同培养5天后,用流式细胞仪检测CD4+CD25+T细胞比例;同时用RT-PCR检测培养细胞中Foxp3的表达水平。②在第一部分实验基础上,通过MACS分离获取C57BL/6小鼠CD4+CD25-T细胞,用同种抗原刺激后,给予TGF-β1干预,培养5d后分离CD4+CD25+T细胞,利用混合淋巴细胞培养系统检测其抑制淋巴细胞增殖的能力。结果T细胞经同种抗原刺激后,在中、高浓度TGF-β1诱导下CD4+CD25+T细胞比例均明显升高,Foxp3的表达水平也相应增加,与对照组相比有显著性差异(P<0.05)。TGF-β1可直接诱导CD4+CD25-T细胞转化为CD4+CD25+T细胞,转化后的CD4+CD25+T细胞可有效抑制淋巴细胞增殖。结论TGF-β1可诱导CD4+CD25-T细胞转化为CD4+CD25+Treg,促进其表达Foxp3,并能够抑制淋巴细胞增殖。

Objective To investigate the capability of TGF-β1 to induce the differentiation of CD4^＋ CD25^＋ regulatory T cells and the mechanisms. Metheds The nude Balb/c splenocytes pretreated with mitomycin as the stimulator were added to C57BL/6 T cells with or without TGF-β1 for a 6-day culture. Four groups were established： control group （0 ng/mL TGF-β1）, low concentration group （0.1 ng/mL）, middie concentration group （5 ng/mL）, and high concentration group （ 10 ng/mL）. At the end-point of culture, the percent of CD4^＋ CD25^＋ T cells and the expression of Foxp3 mRNA were measured by FACS and RT-PCR, individually. Then CD4^＋ CD25^- T cells were isolated by MACS and stimulated with alloantigen and TGF-β1. After a 6-day culture, CD4^＋ CD25^＋ T cells were isolated and we measured the immunosuppressive activity of these cells. Results The 5 ng/mL and 10 ng/mL TGF-β1 could increase the percent of CD4^＋ CD25^＋ T cell and the expression of Foxp3 mRNA in T cells stimulated by alloantigen （ P 〈 0.05）. TGF-β1 induced CD4^＋ CD25^- T cells to convert to CD4^＋ CD25^＋ T cells which could suppress the proliferation of lymphocytes. Condusion TGF-β1 induces CD4^＋ CD25^＋ regulator T cells from CD4^＋ CD25^- T cells which could express Foxp3 and suppress the proliferation of lymphocytes.