Figure 3. P. histicola challenge increased the frequency and activity of CD4⁺FoxP3⁺ regulatory T cells and tolerogenic DCs.

A) P. histicola treated mice had an increased frequency of CD4⁺FoxP3⁺ Tregs compared with the medium or E. coli treated group. Numbers in scatter plots indicate the percentage of positive cells. B) Histogram plot of Treg frequency in the P. histicola treated and untreated groups. The data presented are the average of 2 independent experiments (n=4 mice per group). C) CD4⁺CD25⁺ Tregs from P. histicola treated mice had increased suppressive activity compared with the medium or E. coli treated group. D) The P. histicola treated group had increased levels of CD103⁺CD11c⁺ DCs in the spleen and MLNs compared with the medium treated group. Numbers in the histogram indicate the percentage of CD103⁺ cells gated from the CD11c⁺ population. Data are from 1 of 3 experiments performed at different times. E) Co-culture of CD11c⁺ cells from the P. histicola treated group with PLP specific CD4 T cells resulted in reduced proliferation compared to medium treated or naïve group. The data are presented as the mean±SD CPM and are the average of 2 independent experiments with n=3 mice per group. F) CD11c⁺ DCs from the P. histicola treated group produced low IL-23 and high IL-10 compared with the medium treated group. The data are presented as the mean±SD CPM and are the average of 2 independent experiments (n=3 mice per group). A single asterisk indicates p≤0.05, double asterisks indicate p≤0.005 and ‘n.s.’ indicates not significant.