Comparison of different cell populations for the induction of CD4⁺CD25⁺ FOXP3⁺ Treg's. (A) Purified CD3⁺ T cells were cultured alone or with the indicated populations: myeloid DCs (Myel DCs), plasmacytoid DCs (PDCs), monocytes (Monos) and B cells. After 7 days of culture, the frequency of CD4⁺ FOXP3⁺ Treg's was assessed by FACS and compared with the frequency of the CD4⁺ FOXP3⁺ Treg's at day 0. Data show a summary of 2 experiments. ^*P < .05 for comparisons with myeloid DCs. (B) The graph depicts fold changes in numbers of CD4⁺ FOXP3⁺ Treg's at day 0 compared with numbers after culture either alone or with myeloid DCs (Myel DCs), plasmacytoid DCs (PDCs), monocytes (Monos), or B cells. ^*P < .05 for comparisons with myeloid DCs. (C) The amount of FOXP3 protein per CD4⁺ FOXP3⁺ cell was examined by determining the geometric mean fluorescence of the FOXP3 expression by FACS at day 7. ^*P < .05 for comparisons with myeloid DCs. Data shown represent means ± SD.