LAG3分子对泡球蚴感染小鼠肝脏B淋巴细胞亚群及其功能的影响

Effect of LAG3 molecule on B lymphocyte subsets and its function in the liver of mice infected with Echinococcus multilocularis

目的 探究淋巴细胞活化基因-3(Lymphocyte activation gene-3,LAG3)分子对泡球蚴感染小鼠肝脏B淋巴细胞亚群及其功能的影响。方法 将野生型(C57-wild-type, WT)和LAG3基因敲除(LAG3-knockout, LAG3-KO)小鼠经肝门静脉注射泡球蚴原头节,感染12周免疫组织化学染色观察小鼠肝脏CD19和α-SMA表达及定位,流式细胞术检测小鼠肝脏B细胞及其各亚群和表面CD80、CD86、MHC-Ⅱ分子的表达情况。结果 泡球蚴感染12周小鼠肝脏LAG3-KO组CD19阳性区及面积占比略高于WT组,但差异均无统计学意义。α-SMA在LAG3-KO组阳性区及面积占比显著高于WT组(t=-3.224、-3.227,P均<0.05)。LAG3-KO组肝脏B细胞表达CD80和MHC-Ⅱ分子的比例显著上调,差异具有统计学意义(t=-2.379、-3.321,P均<0.05)。LAG3-KO组B2细胞占比显著高于WT组,差异有统计学意义(t=-2.695,P<0.05)。LAG3-KO组B1b细胞表达CD80比例亦显著上调,差异具有统计学意义(t=-5.315,P<0.001),而B2细胞表达CD80比例显著低于WT组,且差异具统计学意义(t=2.806,P<0.05)。LAG3-KO组B2细胞表达MHC-Ⅱ分子显著上调,且具统计学差异(t=-4.227,P<0.01)。结论 泡球蚴感染中期12周,LAG3分子影响小鼠肝脏B细胞亚群及功能,并以B2型淋巴细胞尤为显著,LAG3对B细胞的活化以及MHC-Ⅱ类分子表达产生抑制作用,提示其可能参与泡球蚴感染下的B细胞耗竭。

This study was aimed at investigating the effect of lymphocyte activation gene-3(LAG3)on liver B lymphocyte subsets and their functions in WT and LAG3-KO mice infected with Echinococcus multilocularis(E.multilocularis).In a mouse model of E.multilocularis infection,the expression and localization of CD19 andα-SMA in liver were detected by immunohistochemistry.CD80,CD86 and MHC-Ⅱmolecules expressed on B cells and their subsets in mice liver were detected by flow cytometry.After 12 weeks of infection,the area and percentage of CD19 in LAG3-KO group was slightly higher than that in WT group,but the difference was not statistically(t=-1.241、-1.237,P>0.05).The area and percentage ofα-SMA in LAG3-KO group was higher than that in WT group(t=-3.224、-3.227,P<0.05).The proportion of CD80 and MHC-Ⅱmolecules expressed on liver B cells in LAG3-KO group was up-regulated(t=-2.379,-3.321,P<0.05).The percentage of liver B2 cells in LAG3-KO group was higher than that in WT group(t=-2.695,P<0.05).The expression of CD80 on B1b cells in LAG3-KO group was significantly up-regulated(t=-5.315,P<0.001).The proportion of CD80 of B2 cells in LAG3-KO group was lower than that in WT group(t=2.806,P<0.05).The expression of MHC-Ⅱmolecule in B2 cells in LAG3-KO group was up-regulated(t=-4.227,P<0.01).It is suggested that LAG3 molecules affected the B cell subsets and function of mouse liver in the middle stage of E.multilocularis infection,especially B2 lymphocytes.LAG3 molecule exerted an inhibitory effect on the activation of B cells and the expression of MHC-class II molecules,suggesting that it may be involved in B cell exhaustion caused by E.multilocularis.