Supplementing with GM-CSF restores chitin-induced eosinophil migration in LysM ^Cre Amfr ^fl/fl mice. (A) Schematic graph of the chitin-induced eosinophil migration model supplementing with exogenous GM-CSF. (B) Mice were treated as in A. BALF cells were stained with APC-CD11c and FITC-Siglec-F. Eosinophils (Eos, CD11c⁻Siglec-F⁺) and AMs (AMs, CD11c⁺Siglec-F⁺) were identified. (C and D) Eosinophil percentage and number in BALF. (E and F) AM percentage and number in BALF. (G and H) Total cell number and total protein concentration in BALF. (I) Representative histopathology of lung tissues stained with H&E. Scale bars: 2 mm, 400 μm, and 50 μm. Numbers in flow plots indicate percentages. Data shown are representative of three independent experiments (B and I). Each symbol represents an individual mouse, and data are presented as mean ± SD from one representative of three independent experiments (n = 5 mice per group per experiment; C–H). **, P < 0.01; ***, P < 0.001 (two-way ANOVA with Tukey’s post hoc analysis, C–H).