TNF and cystic fibrosis: To simulate the chronic inflammatory environment typically found in the lungs of CF patients [76,77,78], human bronchial epithelial (HBE) in vitro models have been exposed to different stimuli, including lipopolysaccharide (LPS) [79], IFN-γ [80], TNF-α [81], interleukin-17 (IL-17) [82,83] bronchoalveolar lavage fluid (BALF) from pediatric CF patients, and supernatant from mucopurulent material (SMM) collected from explanted CF lungs [84,85].