甘露聚糖结合凝集素诱导DC成熟机制分析

The mechanism of DC maturation induced by MBL

目的:探讨甘露聚糖结合凝集素(Mannan-binding lectin,MBL)诱导人外周血单核细胞(Mo)来源树突状细胞(DC)成熟的机制。方法:从健康成人外周血分离Mo,常规方法体外诱导未成熟DC(imDC),FACS分析DC成熟过程中MBL对CD分子表达的影响,进一步分析MBL与imDC的结合情况;RT-PCR分析DC表面模式识别分子Toll样受体-2(TLR2)和Toll样受体-4(TLR4)的表达;凝胶电泳迁移率法(EMSA)和Western blot分析NF-κB的活性及细胞核移位。结果:FCM分析表明,MBL能够使DC表面CD83、CD86及MHC分子表达升高;MBL能够以Ca2+浓度依赖关系与imDC细胞结合;RT-PCR结果表明MBL能够减少DC表面TLR2和TLR4的表达。EMSA和Western blot分析结果显示,MBL能够增强NF-κB活性及细胞核移位。结论:MBL可通过直接结合imDC表面分子来影响DC模式识别分子的表达并调节信号分子NF-κB活性,提示MBL能够通过配体结合调控DC分化成熟,揭示了MBL调节DC分化成熟有关信号途径。

Objective：To investigate the mechanism of mannan-binding lectin（MBL） on the differentiation and maturation of human peripheral blood monocyte-derived dendritic cells（DCs）.Methods：The monocytes were prepared from the blood of healthy adult volunteers.The immature dendritic cells（imDCs） were induced by 5-day-culture in medium supplemented with rhGM-CSF and rhIL-4.The expressions of CD83,CD86 and MHC-DR on DCs were analyzed by FACS.The interaction of MBL with imDCs was also investigated by FACS,and the levels of toll-like receptor 2（TLR2） and TLR4 mRNA expressions on these cells were determined by RT-PCR.Electrophoretic Mobility Shift Assay（EMSA） and Western blot was used to detect MBL-induced NF-κB activity and translocation in imDCs.Results：The expressions of CD83,CD86 and MHC-DR on the MoDCs were up-regulated by MBL,and that MBL could bind to imDCs directly in a Ca2＋-dependent manner.The mRNA expressions of TLR2 and TLR4 were down-regulated by MBL.MBL increased NF-κB activity and translocation in imDCs.Conclusions：MBL may affect the expressions of toll-like receptors and NF-κB activity in imDCs by binding to imDCs directly,suggesting that MBL can regulation DC maturation through ligand-binding.All these revealed some signaling pathways of MBL regulation of DC maturation.