Low-strength T-cell stimulation by DCs favors Th17 responses. (A) Human CD4⁺ T cells were cultured for 6 days with allogeneic peptidoglycan-activated DCs at either a 1 DC:1 CD4⁺ T cell ratio (DC Hi) or 1 DC:50 CD4⁺ T cell ratio (DC Lo). Expression of IL-17 and IFN-γ was determined by intracellular flow cytometry. Plots are representative of 3 independent experiments. (B) Human CD4⁺ T cells were cultured with autologous DCs at a 1:10 DC:CD4⁺ T cell ratio with decreasing concentrations of SEB (1000-0 pg/mL) for 6 days. Expression of IL-17 and IFN-γ was determined by intracellular flow cytometry. Results are representative of 3 independent experiments.