甘露聚糖结合凝集素对Th17细胞诱导分化的影响

摘要

目的 研究甘露聚糖结合凝集素(mannan-binding lectin,MBL)对辅助性T细胞17(T helper cell 17,Th17)诱导分化的影响.方法 通过MACS分选器从人新鲜脐带血液中分选获得CD4+T细胞,对照组用anti-CD3 McAb和anti-CD28 McAb活化CD4+T细胞并加入适当浓度的IL-6和TGF-β1作为诱导剂,在对照组的基础上加入不同浓度的MBL作为实验组,细胞培养72 h后,利用流式细胞术(FACS)检测各组中Th17细胞比例变化情况;Q-PCR分别检测未加MBL对照组和不同浓度MBL实验组Th17细胞核转录因子维甲酸孤儿受体-γt(retinoid-related orphan receptor-γ-t,RORγt)mRNA表达水平;ELISA检测各组细胞上清液中IL-17A的含量;FACS检测Th17细胞在MBL-/-小鼠和WT小鼠中的变化.结果 FACS分析表明,经体外72 h培养,与对照组相比,MBL能够显著降低Th17细胞的比例;Q-PCR结果显示,MBL能够显著降低RORγt mRNA的表达;ELISA结果显示,MBL能够显著降低IL-17A的表达水平;动物实验结果表明,与WT小鼠相比,MBL-/-小鼠CD4+RORγt+Th17细胞比例显著上升.结论 MBL能够抑制CD4+T细胞向Th17细胞诱导分化.%Objective To investigate the effects of mannan-binding lectin ( MBL) on the differen-tiation of Th17 cells (T helper cell 17, Th17). Methods CD4+T cells were separated in vitro from fresh human cord blood by MACS ( magnetic-activated cell sorting ) separator. Anti-CD3 monoclonal antibody ( McAb) and anti-CD28 McAb were used to stimulate CD4+T cells with IL-6 and TGF-β1 as inducers. Then, these cells were treated with ( MBL group) or without ( control group) different concentrations of MBL. Percentages of Th17 cells in different groups were detected by fluorescence-activated cell sorting( FACS) after 72 hours of culturing. Quantitative real-time PCR ( Q-PCR) was used to analyze the expres-sion of RORγt ( retinoid-related orphan receptor-γ-t) at mRNA level in both control and MBL groups. En-zyme-linked immunosorbent assay (ELISA) was performed to detect the levels of IL-17A in supernatants of cell culture from different groups. FACS was used to detect the percentages of Th17 cells in MBL-/-and wild type ( WT) mice. Results MBL could significantly reduce the percentage of Th17 cells after 72 hours of culturing as compared with the control group. Moreover, MBL could significantly down-regulate the expres-sion of RORγt at mRNA level and decrease the expression of IL-17A. Results of animal experiments showed that the percentages of CD4+RORγt+Th17 cells in MBL-/- mice were significantly higher than those in WT mice. Conclusion MBL can inhibit the differentiation of CD4+T cells to Th17 cells, which is induced by IL-6 and TGF-β1.