The effect of ovalbumin sensitisation and challenge on airway sub-epithelial deposition of type III collagen. Immunostaining of representative saline sensitised/challenged (A)and ovalbumin sensitised/challenged (B) airways for type III collagen 12 days after final challenge. In control lungs staining was localised to the alveolar septa, airway and vessel walls. Airway sub-epithelial staining was increased following ovalbumin sensitisation/ challenge. Scale bar represents 50 μm.