急慢性MCMV感染对小鼠脾细胞Foxp3/T-bet/GATA-3蛋白表达水平的影响  

Influence of murine cytomegalovirus infection on the expression of Foxp3,T-bet,GATA-3 in mice

作　　者：李亚男[1] 方峰[1] 朱单丹[1] 舒赛男[1] 杨助峰[1] 李革[1] 

机构地区：[1]华中科技大学同济医学院附属同济医院儿科学系,武汉430030

出　　处：《中国免疫学杂志》2008年第6期563-566,共4页Chinese Journal of Immunology

基　　金：国家自然科学基金资助项目(30572345)

摘　　要：目的:在整体水平研究鼠巨细胞病毒(MCMV)感染对小鼠辅助性T细胞亚群Th1、Th2和调节性T细胞(Treg)分化特异性转录因子T-bet、GATA-3和Foxp3蛋白表达水平的影响。方法:建立MCMV播散型感染模型,依据主要脏器内病毒滴度,确定感染后28天为本模型急、慢性期界定点。42只模型鼠分别于接种MCMV Smith株后第1、3、7、14、28、45天和60天各处死6只,分离脾细胞;另设42只正常小鼠作为模拟感染对照。Western blot法检测脾细胞中特异转录因子T-bet、GATA-3和Foxp3蛋白表达水平。结果:MCMV感染后第3天T-bet蛋白表达显著增高达峰值,与模拟感染对照组比较有显著差异(P<0.01),随后下降,第28天后降至模拟感染对照组相当水平;而GATA-3蛋白表达在感染后第3天开始升高,第7天达峰值(P<0.01),第14天开始缓慢下降,但至第60天仍显著高于模拟感染对照组(P<0.05);Foxp3蛋白表达在感染后7天明显低于模拟感染对照组,第28天降至最低(P<0.01),第45天和60天表达明显上调,并显著高于模拟感染对照组水平(P<0.05)。结论:感染急性期,MCMV上调Th1/Th2特异性转录因子T-bet和GATA-3的蛋白表达;感染慢性期,MCMV诱导Treg特异性转录因子Foxp3蛋白表达上调,同时显著抑制T-bet和GATA-3蛋白表达,提示CMV诱导Foxp3表达增加可能是其抑制宿主抗病毒免疫,导致慢性持续性感染的重要原因。Objective：To investigate the influence of infection of murine cytomegalovirus （MCMV） on the protein expression of cell differentiation-specific transcription factors T-bet, GATA-3 and Foxp3 for Thl, Th2 and regulatory T cell （Treg）.Methods： A mouse model system with disseminated MCMV infection was established. Forty-two BALB/c mice were intraperitoneally inoculated with appropriate amount of MCMV Smith strain viruses and another forty-two mice served as mocked-infected controls. The day 28 th post-infection was designated to be the demarcation point for acute and chronic infection based on viral load of major visceral organs. At 1 d,3 d,7 d, 14 d,28 d,45 d and 60 d post CMV infection （ p. i. ）, 6 mice from each groups were sacrificed and the splenocytes were prepared by means of routine method. The proteins of T-bet,GATA-3 and Foxp3 in splenocytes were determined by Western blot analysis. Results：The expression of T-bet and GATA-3 were up to the highest on day 3 and 7 p. i. respectively （ P 〈 0.01 ）, then gradually decreased during the period of 28 to 60p. i. The level of T-bet dropped to the similar levels of the controls during day 28 to day 60 p. i. ; whereas the level of GATA-3 though gradually decreased from day 14 to day 60 p. i., but still higher than those of the controls; Meanwhile, the level of Foxp3 significantly decreased from day 7 to day 28p. i. （ P 〈 0.05）, but was markedly up-regulated from day 45 to day 60（ P 〈 0.05）. Conclusion： In the acute infection, MCMV can up-regulate the expression of T-bet and GATA-3,which are beneficial to eliminate the virus.During the chronic period, MCMV could induce much higher expression of Foxp3, and inhibit the expression of T-bet and GATA-3, which is likely to be the reason for suppressing cellular immunity in the infected host and so as to cause a persistent or latent CMV infection.

关 键 词：巨细胞病毒 调节性T细胞 T-BET GATA-3 FOXP3 

分 类 号：R725.1[医药卫生—儿科]