Cell culture

A549 (ATCC, CCL-185), a type II alveolar epithelial cell line from human adenocarcinoma, and human bronchial epithelial cells (HBEC)(ATCC, CRL-3245) were maintained in 5% CO₂ in F-12K Nutrient Mixture medium supplemented with 10% (vol/vol) FCS, 0.3 mg/ml L-glutamine, 100 U/ml penicillin, 100 μg/ml streptomycin, 0.25 μg/ml fungizone and 25 mM HEPES. These REC grown in 10 cm dishes to 90% confluence were washed and changed to serum-free of above medium, followed by stimulation with IL-1β for 24 h. THP-1 cells (ATCC, TIB-202), a human monocytic cell line, was cultured in suspension of RPMI 1640 (GIBCO-BRL, USA), 10% FCS, 2 mM L-Glutamine and 0.05 mM 2-mercaptoethanol (GIBCO-BRL, USA).