IL17A and infection: Neutrophils (defined as Gr1hi CD11b+) made up a greater percentage of BAL cells in WT-infected mice than in ΔPT-infected mice (Fig. 6A) consistent with our earlier data, and 33% of these neutrophils from WT-infected mice were IL-17+, whereas there was a very small number of weakly-staining IL-17+ neutrophils from ΔPT-infected mice (Fig. 6B–E), indicating that neutrophils are also significant IL-17 producers in this infection.