We used CFTR−/− swine (gut-corrected CFTR−/−, Fig. 1a, see “Methods” section) to study how CF airway respond to inhalation of bacteria in vivo, where all components of the regulatory mechanisms are intact, i.e., autonomic12, sensory efferent13, and immune signals14, 15. Here, CFTR is linked to cystic fibrosis.