MRL-lpr狼疮小鼠B细胞表面FcγRⅡB的表达及其意义

Expression and significance of FcγRⅡB of B cells in lupus-prone MRL-lpr mice

摘要:

目的：探讨MRL-lpr狼疮小鼠模型中B细胞表面Fcγ受体ⅡB（FcγRⅡB）的表达情况及其病理意义。方法：构建MRL-lpr狼疮小鼠模型，在4、8、12、20周龄时检测外周血总IgG、抗dsDNA抗体、抗ribosomal P0抗体、抗smRNP抗体含量，分析狼疮小鼠的疾病活动度；流式检测20周龄的MRL-lpr狼疮小鼠外周血及脾脏B细胞表面FcγRⅡB及CD69表达情况，分析FcγRⅡB的表达情况与B细胞活化的关系。结果：随着周龄的增加，MRL-lpr狼疮小鼠外周血总IgG及抗dsDNA抗体、抗ribosomal P0抗体、抗smRNP抗体含量逐渐升高；MRL-lpr狼疮小鼠外周血及脾脏B细胞表面FcγRⅡB表达丰度明显降低（均有P＜0.05），CD69表达水平明显升高（P＜0.05），且正常C57BL/6小鼠脾脏CD69+的活化B细胞FcγRⅡB表达上调，但MRL-lpr狼疮小鼠脾脏CD69+的活化B细胞FcγRⅡB表达无明显变化。结论：MRL-lpr狼疮小鼠B细胞表面FcγRⅡB的表达与B细胞的活化有关，FcγRⅡB的表达异常可能是MRL-lpr狼疮小鼠B细胞异常活化的分子机制之一。

Abstract:

Objective：To study the expression and significance of Fcγ receptor ⅡB（FcγRⅡB） of B cells in lupus-prone MRL-lpr mice. Methods：Peripheral blood of lupus-prone MRL-lpr mice at the age of 4，8，12，20 weeks were collected and serum levels of total IgG，anti-dsDNA，anti-ribosomal P0 and anti-smRNP were detected to analyze the progression of disease. The 20 weeks old MRL-lpr mice were sacrificed and the expression of FcγRⅡB and CD69 of B cells in blood and spleen were detected. The relationship between FcγRⅡB expression and B cell activation were analyzed. Results：The serum levels of total IgG，anti-dsDNA，anti-ribosomal P0 and anti-smRNP were increased with the increase of age. Expression of FcγRⅡB of B cells in blood and spleen was decreased obviously（P＜0.05） and expression of CD69 was increased obviously（P＜0.05） in MRL-lpr mice. What’s more，the CD69 positive activated B cells up-regulated the expression of FcγRⅡB in C57BL/6 mice，and this didn’t happen in MRL-lpr mice. Conclusion：The expression of FcγRⅡB is related to the activation of B cells and altered expression of FcγRⅡB may be one of the mechanisms of B cell over-activation in lupus-prone MRL-lpr mice.