丁酸钠增强未成熟树突状细胞表达吲哚胺2,3双加氧酶抑制T细胞增殖

目的 观察丁酸钠诱导的不成熟树突状细胞(DCs)吲哚胺2,3双加氧酶(IDO)的表达及其在抑制T细胞免疫反应中的作用.方法 用重组人粒细胞-巨噬细胞集落刺激因子(GM-CSF)和白细胞介素(IL)-4诱导人单个核细胞来源的未成熟DCs,6 d后分别加入丁酸钠、脂多糖(LPS)和多细胞因子鸡尾酒组合[肿瘤坏死因子(TNF)-α、IL-6、IL-1β、前列腺腺素E2(PGE2)],24h后收集DCs;流式细胞仪检测Des表型,逆转录-聚合酶链反应(RT-PCR)和实时荧光定量PCR检测IDO mRNA的表达,酶联免疫吸附试验(ELISA)检测IL-12分泌;混合淋巴细胞培养(MLR)检测各组DCs对同种异体T淋巴细胞增殖的影响.结果 丁酸钠诱导的DCs呈现典型未成熟DCs的特征,低表达CD83、CD80和HLA-DR,分泌IL-12水平低.与对照组比较,丁酸钠组和LPS组DCs的IDO mRNA的表达分别升高了(32.03±4.02)倍和(1.01±0.43)倍,而鸡尾酒组则降低(3.31±1.07)倍,差异有统计学意义(P<0.01);丁酸钠诱导的未成熟DCs采用IDO抑制剂1-甲基色氨酸(1-MT)处理后,可以有效刺激T细胞增殖,但其能力仍低于LPS或鸡尾酒法诱导的成熟DCs.结论 丁酸钠可显著增强未成熟DCs的表达IDO,并且IDO过表达在其抑制T细胞增殖中起重要作用.

Sodium butyrate enhances the IDO expression in immature dendritic cells to induce T cells anergy in vitro

Objective To investigate the expression of IDO in immature dendritic cells (DCs) induced by sodium butyrate and its effects on T cells immune reaction in vitro. Methods Human mono-cyte-derived immature DCs were induced with GM-CSF and IL-4 for 6 days,then supplemented with sodi-um butyrate, LPS and cytokines cocktail (TNF-α, IL-6, IL-1β, PGE2) respectively. DCs were harvested af-ter incubation for 24 h. The phenotype of DCs was detected by FCM, IDO mRNA expression by RT-PCR and quantitative real-time PCR,and IL-12 production by ELISA. Mixed lymphocyte reactions (MLR) be-tween DCs and allogeneic lymphocytes were performed to analyze the proliferative response of T cells. Re-suits The DCs induced by sodium butyrate still kept on typical characteristics of immature DCs.lowly ex-pressing CD83, CD80 and HLA-DR, producing low levels of IL-12, and having fewer effects on T cells pro-liferation. In eomparion to the control group, the IDO mRNA expression of DCs was increased by ( 32.03± 4.02 ) fold and (1.01 ± 0.43 ) fold in sodium butyrate and LPS groups, and decreased by (3.31 ± 1.07 ) fold in cocktail group respectively (P <0.01 ). The sodium butyrate induced-DCs could stimulate T cells proliferation effectively in the presence of 1-MT, an inhibitor of IDO, but their stimulating capabilities were still lower than those of the mature DCs induced by LPS or cocktail. Conclusion Sodium butyrate could obviously enhance the IDO expression in immature DCs,which might be a significant mechanism for sodi-um butyrate inducing immature DCs to induce T cells anergy.