GITRL在脂多糖所致树突状细胞免疫麻痹中的作用

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(P0.01)。平均荧光密度值由4.81增加到17.95,差异有统计学意义(P0.01)。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(P0.01),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(P0.05)。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。

Role of GITRL on lipopolysaccharide-induced dendritic cell immune paralysis

Objective To investigate the role of GITRL on lipopolysaccharide (LPS)-induced dendritic cell (DC) immune paralysis.Methods DCs 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 BrdU cell proliferation assay,respectively.Results Compared with the control,LPS especially improved DCs maturation,and the expressions of CD1 1c and CD80 significantly increased from 6.97％ to 16.02％ (P＜0.01),and 2.61％ to 13.35％ (P＜0.01) under LPS stimulation respectively.The expression level of GITRL by mean fluorescent intensity strengthened significantly from 4.81 to 17.95 (P＜0.01),and the positive cell percentage increased from 22.39％ to 49.74％ (P＜0.01).While BrdU-labeled ovaspecific T cell proliferation weakened from 0.532 to 0.419 (P＜0.01),and the percentage of CD4+CD25+Foxp3+Treg in the mixed lymphocyte reaction dramatically heightened from 5.71％ to 8.31％ (P＜0.05).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.