FIG. 2.
Cytokine levels in lung homogenates obtained from mice following an intratracheal challenge with live S. pneumoniae. Female BALB/c mice were exposed to room air (open bars) or cigarette smoke (CS) (solid bars) for 5 weeks, followed by an intratracheal challenge with live S. pneumoniae (104 CFU). Homogenates were prepared from lungs removed from euthanized mice at 24 and 48 h postinfection and were assessed for IL-1β, IL-6, IL-10, MIP-2, and TNF-α as described in Materials and Methods. *, P < 0.05 versus air-exposed mice, by t test.