Figure 3.

RelB overexpression reduces cigarette smoke–induced neutrophilic inflammation. Mice were treated with either the RelB or control virus (two doses of 5 × 10⁸ plaque-forming units per mouse delivered 24 hours apart) and were exposed to either cigarette smoke or filtered air (two 1-hour exposures per day for 3 days). Unlavaged left mouse lungs were formalin fixed, sectioned, stained for neutrophils (red), and counterstained with hematoxylin. Few neutrophils were present in the lungs of air-treated mice (A and B), but neutrophil infiltration dramatically increased after cigarette smoke exposure (C). However, this increase was dramatically reduced after RelB overexpression (D). Black arrows indicate neutrophils.