C57BL/6, St2–/–, or Il33–/–mice were used in the PCA model. Mice were intradermally injected with DNP-IgE followed by retroorbital challenge with DNP-HSA. (A) Ear thickness was measured at 0, 1, and 24 hours after antigen challenge. (B) Inflammatory cell infiltration was analyzed 24 hours after challenge by histological staining by H&E. (C, D) Flow cytometry flow plots and analysis of CD45+Gr-1highSiglec-Flow neutrophils and (E) cytospun BAL cells stained with Diff-quick. Arrows illustrate neutrophils. *P ≤ 0.05, **P ≤ 0.01 and ***P ≤ 0.001 (one-way ANOVA). (F) Ear thickness was measured 24 hours after application of croton oil. Data are from at least 3 independent experiments, and the mean ± SEM from n = 10–18 mice per group in (A) and n = 3–7 mice per group in (D) and (F) are displayed. Data in B, C, and E are representative of at least 3 independent experiments with similar results.