The respiratory epithelium is composed of a mixed population of ciliated, nonciliated, and mucoussecreting cells from proximal to distal airways. The individual characteristics of these cells create not only an effective physical barrier against various noxious substances, but also a highly sophisticated host defense system by producing and releasing a large number of chemical mediators and cytokines. The bronchial epithelium consists of the surface epithelial cells and mucus glands. The surface epithelial cells are made up of three principle cell types: basal, goblet, and ciliated cells, of which the latter two form a suprabasal columnar structure and are necessary for mucociliary clearance. Studies using bronchial epithelial cells (BEpiC) have demonstrated that IL-4 and IL-13 stimulation can modify cellular proliferation, ciliary beating, and mucous production. BEpiC proliferation is also regulated in part by EGF receptor signaling. Cultured tracheal epithelial cells (TEpiC) are a useful in vitro model for studying the function and pathophysiology of the respiratory epithelium. HTEpiC from ScienCell Research Laboratories are isolated from human trachea. HTEpiC are cryopreserved at passage one and delivered frozen. Each vial contains >5 x 105 cells in 1 ml volume. HTEpiC are characterized by immunofluorescence with antibodies specific to cytokeratin18 and/or cytokeratin-19. HTEpiC are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HTEpiC are guaranteed to further expand for 15 population doublings under the conditions provided by ScienCell Research Laboratories. Recommended Medium It is recommended to use Bronchial Epithelial Cell Medium (BEpiCM, Cat. #3211) for culturing HTEpiC in vitro.