Figure 1. IL-4 selectively increases permeability of model airway epithelial cell monolayers. (A) 16 HBE cells were incubated with IL-4 (50 ng/ml) applied to the apical (open bars) or basolateral (closed bars) surface for different time points. (B) Dose response for the indicated concentrations of IL-4 (ng/ml) over time. (C) 16HBE cells were incubated with a cocktail of TSLP+IL-25+IL-33 (50 ng/ml each) for the indicated time points followed by analysis of TEER. All data are expressed relative to TEER measured in control cells (typical values > 550 Ω × cm²), which was set as 100%, and are the mean ± SEM of n = 5−12 experiments; *p < 0.05, **p < 0.001.