provide an excellent model system to study all aspects of epithelial function and disease, particularly those related to airway viral infections, as well as tissue repair mechanisms, signaling changes and potential treatments relevant to lung injuries, mechanical and oxidative stress, inflammation, pulmonary diseases and smoking. When grown on inserts and provided with the liquid/air interface, HBEpC can differentiate into a pseudostriated epithelium and serve as a more physiological 3D tissue model for in vitro studies. The HBEpC shown here were cultured (L) and immunolabeled for cytokeratin 18 (R).