TSLP enhances CD40L-induced bioactive IL-12p70 production by CD11c⁺ DCs. (A) Blood CD11c⁺ DCs were activated for 24 hours in different conditions, and IL-12p70 was measured in the culture supernatant by high-sensitivity protein ELISA. Each triangle represents IL-12p70 production by DCs in a different donor. (B-C) CD11c⁺ DCs were first primed for 24 hours in different conditions, and IL-12p70 was measured by protein ELISA in this first set of supernatants (0-24 hours; □). After extensive washing of the DCs, equal numbers of cells from each initial condition were restimulated for 24 hours, and IL-12p70 was measured in the culture supernatant (24-48 hours; ▪). (B) Priming for 24 hours with medium alone, TSLP, CD40L, or TSLP+CD40L and subsequent 24-hour restimulation with CD40L for all culture conditions. (C) Priming for 24 hours with IL-4 or TSLP (0-24 hours; no IL-12 production) followed by 24-hour restimulation with CD40L, lipopolysaccharide (LPS), or poly(I:C) (24-48 hours). (D) CD11c⁺ DCs were primed for 24 hours with IL-4, TSLP, CD40L, or a combination of these conditions. IL-12p70 and IL-12p40 were measured in the culture supernatant by protein ELISA. Data shown are from 1 of 3 representative independent experiments.