氧化修饰低密度脂蛋白促进人单核细胞源树突状细胞的成熟及活化

Effects of Oxidized-Low Density Lipoprotein on the Immune Function of Monocyte-Derived Dendritic Cells

目的 探讨氧化修饰低密度脂蛋白 (oxidized lowdensitylipoprotein ,oxLDL)和低密度脂蛋白 (lowdensi tylipoprotein ,LDL)对人单核细胞源的树突状细胞 (monocytederiveddendriticcells,MDCs)免疫功能的影响。 方法 采用免疫磁珠法分离人外周血CD14 + 单核细胞 ,经含rhGM CSF(10 0ng/mL)和rhIL - 4 (2 0ng/mL)的Cell gro培养 ,使其分化为MDCs。分别以PBS和LPS(5 0 0 μg/mL)作阴性和阳性 (成熟 )对照 ,观察经5 0 μg/mL的oxLDL和LDL干预 4 8h后 ,流式细胞术检测MDCs表型 (CD1a、CD4 0、CD86、HLA DR) ,混合T淋巴细胞反应检测MDCs对淋巴细胞增殖的影响 ,FITC Dextran检测MDCs吞噬功能 ,ELISA检测细胞培养上清细胞因子 (IL -12、IL - 10和TNF α)浓度。结果 与PBS相比 ,5 0 μg/mLoxLDL干预的MDCs,不但可明显上调共刺激分子CD86的高表达 ,而且反映MDCs成熟程度的CD1a也表达增强 ,与此同时经oxLDL处理的MDCs吞噬作用却明显减弱 ,进一步的混合T淋巴细胞反应显示经过oxLDL刺激的MDCs促T细胞增殖作用明显增强 (P <0 .0 5 ) ;此外 ,oxLDL可明显促进MDC分泌细胞因子TNF α、IL - 10和IL - 12 (P <0 .0 5 ) ,但明显弱于LPS组 ,而LDL无此作用。结论 oxLDL在促进DCs成熟的同时 。

Purpose: To explore the influence of oxidized low-density lipoprotein (oxLDL) on the immune function of monocyte derived dendritic cells (MDCs). Methods: Monocytes were purified (over 98%) using anti-CD14 microbeads, after 5 day's culture with DCs Cellgro medium containing rhGM-CSF (100 ng/mL) and rhIL-4 (20 ng/mL), immature MDCs were derived, 50 μg/mL LDL and oxLDL were added to the medium for 48 hours, PBS and LPS (500 μg/mL) were as the negative and positive control; FACS was used to investigate the immunophenotypic expression (CD1a, CD40, CD86, and HLA-DR), FITC-Dextran was used to analyze the endocytosis function, allogeneic mixed T lymphocytes reaction and supernatants' cytokine measurements were used for immune functional assays. Results: Compared with LDL and PBS, oxLDL treated MDCs up-regulated CD86 and CD1a expression, decreased the endocytosis and promoted allogeneic T cells proliferation. Furthermore, the cytokines (IL-12, IL-10 and TNFα) secretion of oxLDL group were increased (P < 0.05). Conclusions: oxLDL can promote the maturation of DCs and augments their capacity to stimulate T-cell proliferation and cytokine secretion. These effects of oxLDL on DCs may contribute to the immunopathogenesis of atherosclerotic lesions.