HDM-induced IL-9 production by T cells depends on IL-25 signaling to DCs. (A) Number of IL-9+ CD4+TCRβ+ cells in total lung of WT, and IL-17 RB KO, CD11c Δ RB or CCL17KO mice, isolated 24h after last of 3 challenges with HDM or PBS. Individual mouse data from three independent experiments shown. (B) Relative expression of Il9 in total lungs of WT and CD11c Δ RB or CCL17KO mice after challenge as in (A). Data shown as mean± sem, based on two independent experiments, each with 3–4 mice/genotype/condition. * p < 0.05.