Fig. 4.

Flagellin activates Cl⁻ secretion in primary cultures of human bronchial epithelial cells. A: confluent cells incubated with equal [Cl⁻] in both apical and basolateral solutions. Amiloride (10 μM), S. typhimurium flagellin (10⁻⁶ g/ml), forskolin (20 μM), and ATP (100 μM) were added to the apical solution as shown by arrows. Responses are typical of 6 similar experiments. B: confluent cells incubated with transepithelial gradient of [Cl⁻], 0 mM Cl⁻ in apical, and 132.4 mM Cl⁻ in basolateral solution. Amiloride, flagellin, forskolin, ATP, and GlyH101 (20 μM) were added to the apical solution at arrows. Responses are typical of 12 similar experiments.