Fig. 2

Photomicrographs of representative tissue sections prepared from lungs of designated mice 4 days after the final antigen challenge.

(A) µMT lung sensitized with saline. Minimal lymphoid cell infiltrate is apparent in the periarterial space adjacent to a normal bronchiole. Alveolar spaces are not involved. This was not different from that seen in C57BL/6 mice sensitized with saline. Inset: PAS staining reveals absence of goblet cells in epithelial cell layer. (B) C57BL/6 lung sensitized with Aspergillus extract. Periarteral space is filled with an eosinophil-rich infiltrate. Airway contains many pale-staining, vacuolated goblet cells (arrow). Inset: PAS stain highlights hyperplasia of purple-staining goblet cells in epithelial cell layer. (C) µMT lung sensitized with Aspergillus extract. The periarterial space is filled with an eosinophilic inflammatory infiltrate that spreads to the adjacent bronchiole. (D) µMT lung sensitized with Aspergillus extract and treated with anti-IL-5 antibody. The perivascular and peribronchiolar spaces are filled with a lymphoid infiltrate containing only rare eosinophils. (E) RAG-deficient lung reconstituted with CD4⁺ T cells and sensitized with Aspergillus extract. A heavy perivascular infiltrate with eosinophils is present surrounding the peribronchiolar space. (F) High-power field of D demonstrating marked reduction in numbers of eosinophils after treatment with anti-IL-5 antibody. (G) High-power field of E demonstrating homogeneous eosinophil-rich infiltrate. All sections stained with hematoxylin and eosin. A–E, × 250 magnification; F, G ×1500 magnification.