Modulation Of Dendritic Cells And CD4~+T Cells In The Mice Lungs During Streptococcus Pneumonia

PARTⅠ MODULATION OF DENDRITIC CELLS AND TREGS IN THE MICE LUNGS AFTER NEONATAL STREPTOCOCCUS PNEUMONIAObjective:To investigate the alteration of dendritic cells(DCs) and Tregs cells in lung after neonatal Streptococcus pneumoniae(S.p) infection.Methods:6-8 weeks old pregnant BALB/c mice were fed and then the neonatal mice(7 days old) were divided into Streptococcus pneumoniae infection groups and mock infection groups. The levels of CD103+DC,CD11b+DC and CD4+CD25+Foxp3+Tregs were detected by flow cytometry in lungs on 2nd, 5th,7th and 14 th day after infection.Results:On 2nd day after infection,the level of CD103+DCs in S.p group was significantly decreased as compared with mock infection groups(P<0.05),and to the least on 5nd day(P<0.01),then increased gradually on 7th and 14 th day(P<0.01,P<0.05).the level of CD11b+DCs in S.p groups was elevated gradually on 2nd day(P<0.001),and to the peak on 5th day(P<0.01),then dropped on 7th day but higher than the mock group(P<0.01),increased gradually on 14 th day(P<0.05).On 5th,7th and 14 th day after infection,the level of Tregs in S.p group was decreased as compared with mock infection groups(P<0.05,P<0.001,P<0.01).The level of IL-17A+CD4~+T cells in S.p group was peak on 2nd day after infection,then decreased gradually on 5th,7th and 14 th day after infection,but all of them were higher as compared with mock infection groups(P<0.001). there was positive correlation between CD103+DCs and Foxp3+Tregs in mock-infected lungs(P<0.01,r=0.593); there was no correlation between CD103+DCs and Foxp3+Tregs in S.p-infected lungs(P>0.05,r=0.015).Conclusion: Neonatal Streptococcus pneumonia infection suppresses CD103+DCs and Tregs prodution, induces CD11b+DCs production, and affects lung homeostasis.PARTⅡ MODULATION OF DENDRITIC CELLS AND CD4~+T CELLS IN THE MICE LUNGS DURING ADULT STREPTOCOCCUS PNEUMONIAObjective: To investigate the alteration of dendritic cells(DCs) and CD4~+T cells after Streptococcus pneumoniae(S.p) infection.Methods:6-8 weeks old BALB/c mice were divided into S.p infection and mock infection groups. The levels of CD103+DCs, CD11b+DCs, p DCs, the subsets of CD4~+T cells in lungs and the levels of CD103+DCs, CD11b+DCs in MLNs were detected by flow cytometry on 2nd, 5th day after infection.Results:After 2 and 5 days infection,CD103+DC and p DC levels of lungs in S.p infection groups were significantly elevated as compared with mock infection groups(P<0.01), the levels of CD11b+DC in infection groups were significantly decreased when compared with mock infection groups(P<0.05).After 2 and 5 days infection,CD103+DC levels of MLNs in S.p infection groups were gradually elevated as compared with mock infection groups(P=0.07,P<0.01), the levels of CD11b+DC in S.p infection groups were no significantly difference when compared with mock infection groups(P=0.482,P=0.485). IL-17A+CD4~+T cells and Foxp3+Tregs levels in S.p-infected groups were increased compared with mock-infected groups on 2nd and 5th day after infection(P<0.05).IL-4+CD4~+T cells level was similar between mock and S.p infection group, while IFN-γ+CD4~+T cells were significantly increased 5 days post S.p infection when compared with mock-infected group(P<0.01).Conclusion: Streptococcus pneumoniae infection induces CD103+DC, p DC production, promotes IL-17A+CD4~+T cells,Tregs production in lungs and induces accumulation of CD103+DC in MLNs to accelerate Streptococcus pneumonia elimination and maintain homeostasis.