FIG. 5.

Inhibition of NTHi LOS stimulation of 9HTEo− IL-8 secretion. Monolayers of cultured human tracheal epithelial cells (3 × 10⁶ cells/well in six-well tissue culture plates; serum-free culture medium) were coincubated with tissue culture medium alone, IL-1β (20 ng/ml), LOS (0.21 μg/ml), and NTHi strain AAr176p⁺ cells (5 × 10⁷ CFU/ml) with or without polymyxin B (0.05, 0.5, 5.0, and 50.0 μg/ml). Culture fluid was harvested after 16 h of coincubation with various stimuli, and secreted IL-8 was measured using commercially available ELISAs. The results are shown as nanograms of IL-8 per milliliter of culture fluid. Error bars each represent the standard error of the mean of three different wells each analyzed in triplicate by ELISA. Unstimulated control wells showed no IL-8 secretion.