慢性乙型肝炎病毒感染者Mg2+转运蛋白1表达水平对CD8+T细胞耗竭的影响

Effect of the expression level of Mg2+ protein transporter 1 on CD8+ T cell exhaustion in patients with chronic HBV infection

目的探讨慢性乙型肝炎病毒(HBV)感染者外周血CD8^+T细胞中Mg^2+转运蛋白1(MagT1)的表达水平及其表达对CD8^+T 细胞耗竭的影响。方法选取2016年6月至2018年1月本院收治的未经抗病毒治疗的HBV感染者86例,根据外周血HBV DNA水平将慢性HBV感染者分为高病毒载量组(45例)与低病毒载量组(41例),并设置健康对照组(20例)。采集外周血、分离CD8^+T细胞,检测各组外周血及CD8^+T 细胞中Mg^2+含量;采用Western blot 和实时荧光定量PCR 法检测各组CD8^+T 细胞中MagT1 蛋白和mRNA表达水平;采用流式细胞术检测各组CD8^+T细胞表面分子T细胞免疫球蛋白黏蛋白3(Tim-3)、程序性死亡受体1(PD-1)、自然杀伤细胞活化受体(NKG2D)和CD38的表达水平;并分析MagT1蛋白表达水平与CD8^+T细胞表面分子表达水平的相关性。结果各组外周血中Mg^2+浓度差异无统计学意义(P>0.05)。与健康对照组比较,慢性HBV 感染者CD8^+T细胞中Mg^2+浓度、MagT1 蛋白和mRNA 表达水平以及表面分子NKG2D和CD38均显著下降(均P<0.05),PD-1和Tim-3表达显著增加(均P<0.05)。并且,CD8^+T细胞中MagT1蛋白与PD-1、Tim-3表达呈负相关(均P<0.05),与NKG2D、CD38表达呈正相关(均P<0.05)。结论慢性HBV感染者CD8^+T细胞耗竭与CD8^+T细胞中MagT1表达下调所致的Mg^2+内流障碍有关。

Objective To investigate the expression level of Mg2^+ transporter protein 1 (MagT1)in peripheral blood CD8^+T cells of patients with chronic hepatitis B virus(HBV),and its effect on CD8^+T cell exhaustion.Methods From June 2016 to January 2018,86 patients with HBV infection without antiviral therapy and 20 healthy controls were selected in our hospital.According to peripheral blood HBV DNA levels,HBV infected patients were divided into the high viral load group and the low viral loadgroup.Peripheral blood was collected and CD8^+T cells were isolated.The levels of Mg^2+ in peripheral blood and CD8^+T cells were detected.The protein and mRNA expression of MagT1 in CD8^+T cells was detected by Western blot and real-time quantitative PCR.The expression levels of Tim-3,PD-1,NKG2D and CD38 on CD8^+T cell were detected using flow cytometry.The correlation between MagT1 protein expression level and CD8^+T cell surface molecule expression level was analyzed.Results There was no significant difference in the concentration of Mg2^+ in peripheral blood of each group(P > 0.05).Compared with healthy control group,the levels of Mg^2+,MagT1 protein and mRNA,and surface molecules NKG2D and CD38 were significantly decreased in CD8^+T cells of patients with HBV infection(all P < 0.05),and the expression levels of PD-1 and Tim-3 were significantly increased(all P < 0.05).Moreover,the protein expression of MagT1 in CD8^+T cells was negatively correlated with the expression of PD-1 and Tim-3(all P < 0.05),and positively correlated with the expression of NKG2D and CD38(all P < 0.05).Conclusion CD8^+T cell exhaustion in chronic HBV infection may be related to Mg^2+ influx disorder caused by the down-regulation of MagT1 expression in CD8^+T cells.