摘要
目的在整体水平研究小鼠巨细胞病毒（MCMV）急慢性感染对小鼠脾细胞中调节性T细胞（Treg）比率和Th1／Th2特异性转录因子T—bet/GATA-3蛋白表达的影响。方法建立MCMV播散型感染模型，60只模型鼠分别于接种病毒后第1、3、7、14、28、45、60、75、90和120天各处死6只，分离脾细胞；另设60只正常小鼠作为模拟感染对照。流式细胞术检测Treg比率，Western印迹法检测T-bet/GATA-3蛋白表达水平。结果Treg比率在急性感染末期（28d）明显低于模拟感染对照组[（1．46±0．27）％vs（2．78±0．29）％，P〈0．05]；在感染慢性期持续表达上调，60d时显著高于模拟感染对照组[（4．51±0．24）％vs（2．69±0．12）％，P〈0．05]。T—bet和GATA-3蛋白表达在感染后3d分别增至（O．618±0．053）和（0．836±0．061），均显著高于模拟感染对照组水平[（0．205±0．026）和（0．398±0．022）]；但是进入感染慢性期后均持续表达下调，在75、90和120d时均明显低于模拟感染对照组水平。结论感染急性期MCMV上调T-bet和GATA-3的蛋白表达；感染慢性期MCMV诱导Treg增殖活化，抑制Th1和Th2分化扩增，CMV诱导Treg扩增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 explore the effects of acute and chronic murine cytomegalovirns （MCMV） infections on the regulatory T cells （Treg） ratio and protein expression of the Th1/Th2 transcription factors T-bet/GATA-3. Methods 120 BALB/c mice were randomly divided into 2 equal groups： MCMV-infected group undergoing infra-peritoneal injection of homogenate of salivary gland containing MCMV, and mock infection group undergoing infra-peritoneal injection of normal homogenate of salivary gland 1, 3, 7, 14, 28, 45, 60, 75, 90, and 120 days after infection 6 mice from each group were killed to examine the viral load of the heart, lung, liver, and kidney by plaque assay to access the status of MCMV infection. Suspension of splenocytes was prepared. The proportion of CD4^＋ CD25^＋ Foxp3^＋ Treg in the splenocytes was measured by flow cytometry. Western blotting was used to detect the protein expression of T-bet/GATA-3. Results The cutoff point between acute and chronic points was the 28th day. The CD4^＋ CD25^＋ Foxp3^＋ Treg proportion in splenocytes significantly decreased during the acute infection stage and to the lowest level of （ 1.46 ± 0.27 ） % at day 28, significantly lower than that of the mock infection group [ （2.78 ± 0.29 ） %, P 〈 0. 05 ] ; then obviously increased in the chronic infection stage, increased to （4.51 ± 0.24） % at day 60, significantly higher than that of the mock infection group [ （2.69 ± 0.12） %, P 〈 0.05 ] , and continued to increase still. The protein level （ K value） of T-bet of the MCMV infection group peaked to the level of （0. 618 ± 0. 053 ） on day 3, obviously higher than that of the mock infected group [ （0.205 ± 0. 026） ], then decreased to the level similar to that of the mock infection group on day 28, and was obviously lower than that of the mock infection group on day 75. Whereas the protein level of GATA-3 of the MCMV group increased to （0.836±0.061 ） on day 3, markedly higher than that of the mock infection group （0. 398 ± 0. 022）, peaked on day 7, then gradually decreased, and remained at the levels similar to those of the mock infection group from day 75 to day 120. Conclusion In the acute infection stage, MCMV up-regulates the T-bet and GATA-3 protein expression. But during the chronic infection stage, MCMV induces a marked proliferation and activation of Treg cells which further inhibit the Th1 and Th2 reactions, especially Th1 response. Treg proliferation may be an important mechanism of chronic and persistent CMV infection in the host.
出处
《中华医学杂志》
CAS
CSCD
北大核心
2008年第42期2999-3002,共4页
National Medical Journal of China
基金
国家自然科学基金资助项目（30572345）
作者简介
李亚男现在吉林大学第一医院儿科
通讯作者：方峰，E-mail：ffang@tjh．tjmu．edu．cn
