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目的:通过检测1型糖尿病(type 1 diabetes mellitus,T1DM)、2型糖尿病(type 2 diabetes mellitus,T2DM)患者以及健康对照外周血T细胞亚群免疫负调控分子程序性死亡蛋白1(programmed cell death protein 1,PD-1)mRNA相对表达水平和记忆性T细胞(memory T cells,Tm)表面PD-1表达情况,从分子生物学、细胞免疫学等多种角度研究记忆性T细胞PD-1表达异常与以胰岛β细胞破坏为主要机制的T1DM发生发展的相关性.方法:分离T1DM、T2DM患者以及健康对照组外周血单个核细胞(peripheral blood mononuclear cells,PBMCs);从PBMCs中分离出CD4+T细胞和CD8+T细胞,使用荧光定量PCR分别检测其细胞内PD-1 mRNA相对表达水平;将PBMCs分别标记荧光抗体CD4-FITC、CD45RO-PE、CCR7-APC、CD8-FITC、PD-1-PerCp,应用流式细胞术分别检测CD4+CD45RO+CCR7+Tcm细胞、CD4+CD45RO+CCR7-Tem细胞、CD8+CD45RO+CCR7+Tcm细胞、CD8+ CD45RO+CCR7-Tem细胞表面免疫负调控分子PD-1的表达水平.结果:①T1DM组患者外周血中CD4+T细胞内PD-1 mRNA相对表达水平低于T2DM组和正常对照组,差异有统计学意义;②T1DM组患者外周血中CD8+T细胞内PD-1 mRNA相对表达水平未见明显异常;③T1DM组患者外周血中CD4+CD45RO+CCR7-Tem细胞亚群与CD4+CD45RO+CCR7+Tcm细胞亚群PD-1表达水平均显著低于正常对照组和T2DM组患者,差异有统计学意义;④T1DM组患者外周血中CD8+CD45RO+CCR7-Tem细胞亚群与CD8+CD45RO+CCR7+Tcm细胞亚群PD-1表达水平均无明显异常.结论:胰岛β细胞可通过细胞表面PD-L1与CD4+Tm细胞表面PD-1结合从而负调节后者细胞免疫作用,因此当CD4+Tm细胞PD-1表达异常而失去负调控作用时,细胞效应则会进一步增强,最终可能通过破坏胰岛β细胞而导致T1DM的发生发展.“,”Objective:Through the detection of the relative abundance of immune negative control molecules programmed cell death protein 1(PD-1)mRNA in T-cell subsets and the PD-1 expression on memory T cells from peripheral blood in type 1 diabetes mellitus (T1DM) patients, type 2 diabetes mellitus(T2DM) patients and healthy control separately, to further study the relationship of abnormal expression of PD-1 on memory T cells with the development and progression of T1DM which is characterized by pancreatic βcell destruction. Methods:Peripheral blood mononuclear cells(PBMCs)were isolated from health control, T1DM patients, and T2DM patients separately;PBMCs were further sorted into CD4+ T cells and CD8+ T cells, then the relative abundance of PD-1 mRNA was analyzed by fluorescence quantitative PCR;PBMCs were marked by fluorescent antibody CD4-FITC, CD45RO-PE, CCR7-APC, CD8FITC and PD-1-PerCp separately, then analyzed the expression of PD-1 on CD4+CD45RO+CCR7+Tcm cells, CD4+CD45RO+CCR7-Tem cells, CD8 + CD45RO + CCR7 + Tcm cells and CD8 + CD45RO + CCR7-Tem cells by flow cytometry(FCM). Results:① The relative abundance of PD-1 mRNA in CD4+T cells from the peripheral blood of the T1DM group was significantly lower than that of the T2DM group and the healthy control group;②There was no abnormality for the relative abundance of PD-1 mRNA in CD8+T cells from the peripheral blood of the T1DM group, compared with the T2DM and healthy control groups;③The expression levels of PD-1 on CD4+ CD45RO+CCR7-Tem cells and CD4+CD45RO+CCR7+Tcm cells in the peripheral blood from T1DM patients were significantly lower than those of the healthy control and T2DM group;④There was no significant difference for the expression of PD-1 on CD8+CD45RO+ CCR7-Tem cells and CD8+ CD45RO+ CCR7+ Tcm cells between the T1DM group, the T2DM group and the healthy control group. Conclusion:For PD-L1 which is expressed on islet β cells can combine with PD-1 on CD4+Tm cells to negatively regulate cell immunity, so when the expression of PD-1 on CD4+Tm cells is abnormal, cell effect will be further enhanced for the loss of negative regulation, so it may eventually lead to the development of T1DM by destroying islet β cells.