Repeated allergen challenge with dsRNA enhances both Th1 and Th17 cell responses in the lung. In all the experiments: PBS, mice sensitized with OVA and challenged with PBS; OVA, mice sensitized with OVA + poly(I:C) and then challenged with OVA; IC/OVA, mice sensitized and then challenged with OVA + poly(I:C). Five mice in each group were evaluated 48 h after the final allergen challenge; *, P < .05 compared to the PBS group; **, P < .05 compared to the other groups. (A) Numbers of IFN-γ- and IL-17-producing CD3+ and CD3- cells in the lung tissues. (B) Levels of IP-10 and TGF-β1 in the BAL fluids.