Figure 3.

Chitinase 3-like-1/BRP-39 promotes increased lung cellularity during experimental fungal asthma. A: Balb/c wild-type (WT) and BRP-39-deficient (Chi3l1^−/−) mice were chronically exposed to A. fumigatus as described in the materials and methods. Representative hematoxylin and eosin (H&E)-stained lung sections from naïve and asthmatic WT and Chi3l1^−/− mice. Original magnification ×10. Bar = 1 mm. B: Balb/c wild-type (WT) and BRP-39-deficient (Chi3l1^−/−) mice were chronically exposed to A. fumigatus as described in the materials and methods. Twenty-four hours after last challenge, lung cells from WT and Chi3l1^−/− mice were isolated by bronchoalveolar lavage, enumerated, Fc-blocked, stained with a live/dead staining kit, then stained for neutrophils (CD45⁺CD11b⁺Ly-6G⁺; B), eosinophils (CD45⁺CD11b⁺SiglecF⁺; C), and CD4 T cells (CD45⁺CD3⁺CD4⁺; D), and quantified via flow cytometry. The figure illustrates cumulative data from two independent studies (n = 5 mice per group, per study). Each dot presents a single mouse. The middle line represents the mean. Data are expressed as absolute cell number in lavage fluid. **P value  < 0.01 (two-tailed Student’s t test).