Figure 5. The IFN-γ/IRF1 pathway restricts Th9-dependent allergic airway inflammation.

WT or Irf1^−/− Th9 cells treated with IFN-γ were adoptively transferred into Rag2^−/− mice, which were then challenged with nebulized OVA in the absence or presence of IL-9-neutralizing monoclonal antibodies (anti-IL-9) or control rat IgG (Ctrl) antibodies as outlined in Supplementary Fig. 6. (a,b,f,g) Cell numbers in the BAL fluid are displayed. (b,g) Numbers of mucus-producing goblet cells evaluated by periodic acid-Schiff staining. (c–e) Lung cells were stimulated with 2 mM OVA_323–339 for 3 days. IL-9, IL-13 and IFN-γ production was determined in supernatants by ELISA. (h) Tissue inflammation was evaluated with haematoxylin and eosin staining, original magnification × 100. (a–g) Data are shown as the mean±s.e.m. of 10–15 mice combining two independent experiments. (a–h) The experiments were repeated four times with consistent results. *P<0.05, **P<0.005 by one-way ANOVA with Tukeýs post-test (a,b,f,g) or one-tailed Student's t-test (c–e).