GITRL在脂多糖所致树突状细胞免疫麻痹中的作用

Role of GITRL on lipopolysaccharide-induced dendritic cell immune paralysis

目的观察脂多糖所致脓毒症小鼠树突状细胞GITRL表达及免疫功能的改变。方法以10 ng/mL脂多糖刺激体外诱导小鼠树突状细胞模拟脓毒症免疫麻痹体系,利用流式细胞术和Brd U细胞增殖反应试剂盒分别检测树突状细胞表面分子CD11c、CD80和GITRL表达、混合淋巴细胞增殖反应及CD4^+CD25^+Foxp3^+Treg水平。结果脂多糖引起树突状细胞标志分子CD11c、CD80和负调控分子GITRL的表达分别由6.97%、2.61%和22.39%增加到16.02%、13.35%和49.74%,差异均有统计学意义(P<0.01)。平均荧光密度值由4.81增加到17.95,差异有统计学意义(P<0.01)。然而抗原特异性混合淋巴细胞反应OD值由0.532减少为0.419,差异有统计学意义(P<0.01),并且GITRL激活的CD4^+CD25^+Foxp3^+Treg由5.71%增加到8.31%,差异有统计学意义(P<0.05)。结论脂多糖所致脓毒症小鼠树突状细胞表达高水平的免疫共抑制GITRL分子,通过GITRL-GITR激活Treg细胞抑制T细胞增殖和功能,引起免疫麻痹状态。

Objective To investigate the role of GITRL on lipopolysaccharide（LPS）-induced dendritic cell（DC）immune paralysis.MethodsDCs were generated from bone marrow cells of mice and stimulated with LPS treatment to imitate sepsis immune paralysis state.DCs were collected and their co-stimulatory molecules CD11c,CD80,GITRL expressions,mixed lymphocyte reaction in vitro and CD4＋CD25＋Foxp3＋Treg level were analyzed by flow cytometry and Brd U cell proliferation assay,respectively.Results Compared with the control,LPS especially improved DCs maturation,and the expressions of CD11c and CD80 significantly increased from 6.97%to 16.02%（P0.01）,and 2.61%to 13.35%（P0.01）under LPS stimulation respectively.The expression level of GITRL by mean fluorescent intensity strengthened significantly from 4.81to 17.95（P0.01）,and the positive cell percentage increased from 22.39%to 49.74%（P0.01）.While Brd U-labeled ovaspecific T cell proliferation weakened from 0.532 to 0.419（P0.01）,and the percentage of CD4＋CD25＋Foxp3＋Treg in the mixed lymphocyte reaction dramatically heightened from 5.71%to 8.31%（P0.05）.Conclusion The LPS intervention can induce the higher expression level of immune co-inhibitory molecule GITRL which arranges T cell proliferation suppression by GITRL-GITR interaction to active Treg,causing immune paralysis in sepsis.