IL-10–secreting T cells are activated both by PDCs and CD11c⁺ DCs and acquire the ability to produce IFN-γ during culture. IL-10–producing cells were immunomagnetically isolated from cocultures of CD4⁺ T cells and PDCs following 36 hours of SEB stimulation. After a 5-day resting period, the cells were restimulated for 48 hours with autologous PDCs or CD11c⁺ DCs in the absence or presence of SEB, as indicated. IL-10 and IFN-γ were measured in the supernatants with CBA. Two separate experiments are shown, indicated by distinct symbols.