Pulmonary overexpression of IL-9 induces Th2 cytokine expression, leading to immune pathology
J. Clin. Invest. Ulla-Angela Temann, et al. 109:29 doi:10.1172/JCI13696 [Go to this article.]

Figure 5
Histologic staining for mucin and mast cells. Lung sections from IL-9 transgene-negative (a) or -positive (b–d) mice were stained with AB/PAS for light microscopic identification of mucin-containing cells. Intense, positive (purple) staining for mucin was observed in hypertrophied airway epithelial cells from IL-9 transgene-positive mice after 7 days (c) (arrow) and 14 days (d) (arrow) of transgene induction by doxycycline. In lung sections from transgene-positive mice that did not receive doxycycline some mucin-positive epithelial cells were also detected (b) (arrow). Airway epithelium from transgene-negative mice did not stain for mucin (a). For the identification of mast cells, lung sections from transgene-negative (e) or -positive (f) mice were stained with toluidine blue. Dark blue–stained mast cell granules (arrow) were present in the airway epithelium from transgene-positive mice that were housed with doxycycline-supplemented food over a period of 14 days (f), but not in transgene-negative mice (e). Original magnification: a–d, ×300; e–f, ×600.