MRL-lpr狼疮小鼠CD4+CD25+调节性T细胞及相关基因探究.docVIP

MRL/lpr狼疮小鼠CD4+CD25+调节性T细胞及相关基因探究 　 作者：卢雪红 田庚 杨巍 李一 顾华 【摘要】 　　目的 通过研究MRL/lpr系统性红斑狼疮（SLE）小鼠（模型组）胸腺、脾脏中CD4+CD25+调节性T细胞（Tr）数量和相关基因的变化，探讨Tr在SLE发病中的作用。方法 采用间接免疫荧光法检测模型组和对照组血清中抗核抗体水平，流式细胞术检测胸腺、脾脏中Tr数量，RTPCR检测Tr功能基因表达水平。结果 抗核抗体模型组均为阳性，而对照组均为阴性；胸腺、脾脏中Tr数量模型组与对照组无明显差别；Foxp3的表达水平在模型组胸腺中与对照组无明显差别，而在模型组脾脏中却低于对照组；CTLA4的表达水平在模型组胸腺和脾脏均高于对照组。结论 Tr数量的变化在MRL/lpr小鼠的发病中不起关键作用，而Tr功能的变化，尤其在外周的功能缺陷可能是其发病的原因之一，至于Tr的抑制功能是否真正发生变化，还有待于进一步通过体外抑制功能的检测来确定。 【关键词】 MRL/lpr小鼠；系统性红斑狼疮；CD4+CD25+调节性T细胞；小鼠 【Abstract】Objective To investigate CD4+CD25+ regulatory T cells and target genes in thymus and spleen of MRL/lpr mice. Methods Serum antinuclear antibody was detected by indirect immunofluorescence. CD4+CD25+Tr was determined by flow cytometry and its target genes were detected by RTPCR. Results Antinuclear antibody was positive in model group but negative in control group. There were no significant differences of CD4+CD25+Tr in model and control groups. Foxp3 levels of model group was no significant difference in thymus but lower in spleen compared with that of control group. CTLA4 levels of model group had higher than those of control group both in thymus and in spleen. Conclusions MRL/lpr mice do not occur as a result of reduced level of CD4+CD25+Tr, but function defect of CD4+CD25+Tr may be responsible for its occurrence. But the suppressive effect of CD4+CD25+Tr is still need to be confirmed by vitro test. 【Key words】MRL/lpr; Systemic lupus erythematosus; CD4+CD25+ regulatory T cells; Mouse 　　CD4+CD25+调节性T细胞(regulatory T cell，Tr)是健康个体T细胞群的重要成员，通过与靶细胞的相互接触、下调靶细胞上白介素(IL)2Rα的表达，以及抑制抗原提呈细胞(APC) 提呈抗原而抑制免疫应答。除CD25外，这群细胞还表达多种分子，与其功能的发挥密切相关，如CTLA4，GITR，Foxp3等，尤其是Foxp3可特异性表达在Tr细胞上。很多研究发现，Tr数量减少可导致器官特异性自身免疫性疾病的发生〔1〕，但在器官非特异性自身免疫病〔如系统性红斑狼疮（SLE）〕中的作用报道不多，因此探讨Tr在SLE中数量和功能的变化将为这一类疾病的发病机制和寻找新的治疗靶点奠定基础。 　　MRL/lpr小鼠是常用的SLE 动物模型之一，其症状与人类SLE相似，含有与细胞自发性程序性死亡有关的Fas 基因隐性突变〔2〕，出现淋巴细胞增生基因，导致T 细胞增生，全身淋巴结肿大，加速了自身免疫反应。Hori等〔3〕的研究表明Foxp3基因敲除的小鼠会出现明显的淋巴增生而导致自身免疫病的发生，那么Tr数量及其功能的变化是否参与MRL/lpr小鼠的发病呢？本文选用MRL/lpr小鼠