Figure 3

Capacity of the two bacterial strains to activate BMDCs and to promote either Treg or Th17 T cell responses in vitro. (A) Effect of the two strains on BMDC maturation. BMDCs derived from C57BL/6J mice were stimulated for 24 hrs by bacteria (10:1) and the expression of activation markers CD40, CD80, CD86 and MHCII was followed by flow cytometry. Isotype control is represented by open histogram with dotted line. Expression of activation markers on nonstimulated BMDCs is represented by an open histrogram with solid line. Expression of activation markers on BMDCs stimulated by bacteria is shown by a filled histogram (red for Bl 5764 and blue for Lr 5454). Percentages of positive cells ± SEM are indicated. Representative results of 6 independent experiments are shown. (B) Comparison of MFI (Mean of Fluorescence Intensity) of activation markers. Bacteria-primed BMDCs were co-cultured with naïve CD4⁺ T cells (1:10) for 6 days. (C) Detection of Tregs (CD4⁺CD25⁺FoxP3⁺) identified from population of CD4⁺ T cells according to the presence of cell surface marker CD25 (PE) and intracellular transcription marker FoxP3 (PE-Cy5) by flow cytometry; representative dot plots with mean and SEM from 6 independent experiments. (D) Detection of intracellular cytokines IL-10, IL-17A and IL-17F in CD4⁺ T cells. *Refers to the comparisons of bacteria-treated cells versus untreated cells; *p < 0.05, **p < 0.01, ***p < 0.001.