Figure 3.

Histopathologic pulmonary changes accompany lung epithelial expression of IL-5. (a) Wild-type, (b–d) NJ.1726, and (e) a transgenic mouse expressing IL-5 from T cells (line NJ.1638 [22]) were stained with hematoxylin and eosin before bright-field photomicroscopy. b and c are representative photographs of the variation in phenotype found in NJ.1726 mice. The arrows in c indicate airways in an NJ.1726 mouse nearly occluded by the expansion of peribronchial lymphoid tissue. The high magnification view of a BALT aggregate (d) shows in greater detail the additional histopathologies associated with these regions. e demonstrates that although T cell–specific expression of IL-5 elevates serum levels to 400–800 pg/ml, no pulmonary changes occurred, and thus the pathologies occurring in NJ.1726 mice are the result of lung-specific IL-5 expression. B, bronchiole; PV, pulmonary blood vessel; AS, alveolar space; BALT, bronchus-associated lymphoid tissue. Bars: (a–c, e) 200 μm; (d) 50 μm.