DIFFERENCES IN SECRETORY PROFILES OF EPITHELIAL-CELL CULTURES DERIVEDFROM HUMAN TRACHEAL AND BRONCHIAL-MUCOSA AND SUBMUCOSAL GLANDS

The respiratory tract contains macromolecules produced by various epit helia including tracheal and bronchial mucosa and submucosal glands. T he objectives of this study were to elucidate and compare the growth a nd secretory profiles of epithelial cell cultures derived from the hum an tracheal (TC) and bronchial mucosa (BC) and submucosal glands (GC). Most experiments were done on third to fourth passage cultures. Secre tory glycoconjugates were characterized by a combination of gel filtra tion and anion-exchange chromatography after enzymic digestion with hy aluronidase [H-3]glucosamine and [S-35]sulphate incorporated glycoconj ugates secreted into the culture medium. Intracellular mucin-like glyc oproteins were characterized by immunohistochemical staining with a hu man monoclonal respiratory mucin antibody. Results showed that the thr ee cell types exhibited variable growth rates and secretory profiles. Doubling times of GC, BC and TC were 53, 75 and 80 h respectively. Imm unocytochemical staining with the mucin antibody demonstrated positive reaction in GC and BC; TC showed no significant reaction. Mucin-like glycoproteins were detected in the spent media of GC and BC whereas TC , under the same conditions, did not produce any detectable amount of the glycoconjugates. Further, the mucin-like materials produced by GC and BC differed in their relative glycosylation and sulphation levels. The production of mucin was independent of substrate and vitamin A as the cultures were propagated on the plastic surfaces and the culture medium lacked vitamin A.