MUCINS SECRETED BY A TRANSFORMED-CELL LINE DERIVED FROM HUMAN TRACHEAL GLAND-CELLS

High-molecular-mass glycoconjugates are secreted by the continuous cel l line MM-39, which has been obtained from cultured human tracheal gla nd cells transformed by simian virus 40. They were purified on Sepharo se CL-4B and then by two steps of density-gradient centrifugation. Hig h-molecular-mass glycoproteins resistant to digestion by hyaluronidase , chondroitin ABC lyase and heparitinase were obtained, in addition to hyaluronic acid and proteoglycans. They were susceptible to beta-elim ination. They contained polylactosaminoglycan chains as well as carboh ydrate chains with a terminal sialic acid in the NeuAc alpha2-3 sequen ce. Most of them have a buoyant density of 1.45 g/ml in CsCl-density-g radient centrifugation, except for MUC1. The MM-39 cells were also cha racterized by a high expression of MUC1 and MUC4 genes, but they did n ot express MUC2, MUC3, MUC5B and MUC5AC. Therefore the MM-39 cells syn thesized mucin-like glycoproteins as well as lysozyme and mucous prote inase inhibitor [Merten, Kammouni, Renaud, Birg, Mattei and Figarella (1996) Am J Respir Cell Mol Biol 15, 520-528]; they should be consider ed as having a mixed, both serous and mucous, phenotype.