肺炎链球菌肺炎对肺部树突状细胞及CD4^+T细胞的影响

Modulation of dendritic cells and CD4^+T cells in mouse lungs during Streptococcus pneumonia

目的探讨肺炎链球菌肺炎对Balb/c小鼠肺部树突状细胞及CD4^+T细胞的影响。方法 6~8周Balb/c小鼠随机分为对照组及肺炎链球菌感染组,流式细胞术检测肺炎链球菌感染后2 d、5 d肺组织中CD103^+DCs、CD11b^+DCs、p DCs及CD4^+T细胞亚类水平。结果肺炎链球菌肺炎致肺组织CD103^+DCs及p DCs水平显著增高,与对照组比较差异有统计学意义(P<0.01),而肺组织CD11b^+DCs水平显著低于对照组。肺炎链球菌肺炎促进肺组织IL-17A^+CD4^+T细胞和Foxp3^+Tregs表达,与对照组比较,感染后2 d、5 d差异均有统计学意义(P<0.05),随着感染控制,Foxp3^+Tregs表达水平回降,感染后5 d Foxp3^+Tregs水平显著低于感染后2 d水平(7.3%±0.41%vs 9.38%±1.34%,P<0.01)。肺炎链球菌肺炎对肺部Th2表达水平无显著影响,感染后5 d IFN-γ^+CD4^+T细胞水平显著升高,与对照组、感染后2 d组比较,差异有统计学意义(P<0.01)。结论肺炎链球菌肺炎促进肺组织CD103^+DCs、p DCs表达,诱导CD4^+Th17、Tregs细胞分化发育。

To investigate the alteration of dendritic cells（DCs） and CD4^＋T cells after Streptococcus pneumoniae（S. pneumonia） infection, 6-8 weeks Balb/c mice were divided into Streptococcus pneumonia infection and mockinfection groups. The levels of CD103^＋DC, CD11b^＋DC, p DC and the subsets of CD4^＋T cells in lungs were detectedby flow cytometry on 2^（nd） and 5^（th） day after infection. 2 and 5 days after infection, CD103^＋DC and p DC levels in S.pneumonia infection groups were significantly elevated（P〈0.01）, but the level of CD11b^＋DC was significantlydecreased（P〈0.05） as compared with mock infection groups. IL-17A^＋CD4^＋T cells and Foxp3^＋Tregs levels in S.pneumonia-infected group were increased compared with mock-infected group on 2ndand 5thday after infection（P〈0.05）; IL-4^＋CD4^＋T cells level was similar between mock and S. pneumonia infection group, while IFN-γ^＋CD4^＋Tcells were significantly increased 5 days post S. pneumonia infection when compared with mock-infected group（P〈0.01）. Taken together, S. pneumonia infection can induce CD103^＋DC, p DCs production, promotes IL-17A^＋CD4^＋Tcells and Tregs differentiation.