Lung epithelial integrity in polarized primary bronchial cells was examined by measuring the TEER using an electronic resistance system (Millicell ERS-2, EMD Millipore). Ex vivo-differentiated lung epithelium was grown on ALI in 24-transwell plates (Corning, Tewksbury, MA) using BronchiaLife Epithelial Airway Medium in the basolateral compartment. Peptides dissolved in PBS at different concentrations were added onto the apical surface of the differentiated epithelial cells in a final volume of 100 μl. A sterile electrode was applied onto the apical side of the transwell insert containing the cultured epithelial cells with/without peptide treatments and the electrical resistance was measured three times for comparison at different time intervals.