Type IV collagen localization in hamster tracheal epithelial cell cultures

Hamster tracheal epithelial (HTE) cell cultures when grown on collagen coated Millicell-HA filters for 28 d in vitro have an incomplete basal lamina-like structure at the basal plasmalemma/collagen interface. EM evaluation of 42 d HTE cell cultures also revealed the presence of hemidesmosome-like structures on the basal plasmalemma. In order to better characterize this discontinuous basal lamina-like material, HTE cultures at 7, 14, 21, and 28 d were evaluated for the presence of type IV collagen, a basal lamina component. Immunocytochemical treatment of HTE cultures at these time points resulted in the presence of reaction product at the base of the cell layer. When immunocytochemical procedures for the localization of type IV collagen were carried out with normal mouse trachea, the results were also positive. Immunoblotting evaluation of HTE cell supernatants and conditioned media also indicated the presence of type IV collagen. Taken altogether, the presence of what appears to be basal lamina, hemidesmosome-like structures and immunocytochemical and immunoblot data showing the presence of type IV collagen in HTE cultures suggest that HTE cells may be producing basal lamina components but cannot organize them into a complete basal lamina.