Fig. 5: Oral allergen-elicited lung eosinophils exhibit an inflammatory phenotype and their accumulation is accompanied by increased mucus production.

Four days after final oral challenge, mice were sacrificed and lungs perfused with PBS. Lung tissue was digested and disaggregated and frequencies and phenotypes of lung tissue eosinophils analyzed by flow cytometry (a–c) or formalin fixed, paraffin embedded, and stained with PAS to assess mucus secretion (d–f). a–c Lung eosinophils were identified as live, CD45⁺SSC^hiSiglecF⁺ cells after gating out CD11c^hi alveolar macrophages. Within the gated population eosinophils were further categorized as homeostatic (hEos, SiglecF^loCD11c⁻) or inflammatory (iEos, SiglecF^hiCD11c^int) (a, c). Sham control mice were sensitized with PBS-alum and challenged with PBS. Magnification ×100 (d, e); ×200 (inset: d, e). Scale bar, 200 μm. *p < 0.05; **p ≤ 0.005, ***p ≤ 0.0005. P values determined by student’s t test (b, f) or two-way ANOVA with Tukey’s multiple comparisons test (c).