Histological appearance of murine lung 24 hours following final ovalbumin challenge. H&E staining of (A) saline sensitised/challenged and (B) ovalbumin sensitised/challenged airways at 24 hours after final challenge. Control airways did not show any inflammatory cell infiltration. A mixed inflammatory cell infiltrate can be seen around ovalbumin sensitised/challenged airways, particularly in those adjacent to blood vessels where margination and diapedesis of cells are seen. H&E staining of typical areas of parenchyma from (C) saline sensitised/challenged and (D) ovalbumin sensitised/challenged mice are similar, demonstrating the lack of interstitial inflammation produced by this model. PAS/Alcian Blue staining of (E) saline sensitised/challenged and (F) ovalbumin sensitised/challenged airways at 24 hours after final challenge. Most of the epithelial cells are replaced by blue/purple staining goblet cells in ovalbumin sensitised/challenged airways. Scale bar represents 50 μm.