Effect of anti-interleukin-33 monoclonal antibody (IL-33 mAb) on airway inflammation and remodelling after the seventh antigen challenge in IgE-sensitized mice. (a) Experimental protocol for treatment with anti-IL-33 mAb. Anti-IL-33 mAb was intratracheally administered on days 8, 9, 10 and 15 [OE-1 (7th) + anti-IL-33]. Negative and positive controls were non-sensitized-challenged [NS-C (7th)] and OE-1-sensitized-challenged, control rat IgG2a mAb-treated [OE-1 (7th) + rat IgG2a] mice, respectively. (b) Effect of treatment with anti-IL-33 mAb on inflammatory cell number in bronchoalveolar lavage fluid 24 hr after the seventh challenge. (c) Effect of treatment with anti-IL-33 mAb on increased levels of IL-4 (i), IL-5 (ii) and IL-13 (iii) in the lung tissue supernatant 24 hr after the seventh challenge. (d) Effect of treatment with anti-IL-33 mAb on airway inflammation (i), epithelial area (ii), PAS+ area (iii), fibrosis area (iv), total collagen (v) and α-SMA+ area (vi) 24 hr after the seventh challenge. Results shown are from one experiment representative of two independent trials. Each value is the mean ± SEM of six to eight animals. **P < 0·01 compared with the NS-C (7th) group. #P < 0·05 and ##P < 0·01 compared with the OE-1 (7th) + rat IgG2a group. Total, all cells; Mac, macrophages; Lym, lymphocytes; Neu, neutrophils; Eos, eosinophils.