The bronchial epithelium is continuously exposed to a multitude of noxious challenges in
inhaled air. Cellular contact with most damaging agents is reduced by the action of the
mucociliary apparatus and by formation of a physical barrier that controls passage of ions
and macromolecules. In conjunction with these defensive barrier functions,
immunomodulatory cross-talk between the bronchial epithelium and tissue-resident immune
cells controls the tissue microenvironment and barrier homeostasis. This is achieved by …