Isolation and characterization of two types of MDCK epithelial cell clones based on glycosphingolipid pattern

The Madin-Darby canine kidney (MDCK) epithelial cell line was shown previously to be heterogeneous with marked differences reported between low-passage (strain I) and high-passage (strain II) cultures (Richardson, J.C.W., Scalera, V. and Simmons, N.L. (1981) Biochim. Biophys. Acta 673, 26-36). This report describes major differences in the glycolipids of the two subpopulations of cells that comprise strain I and strain II cultures. The majority of strain II cells were strongly positive for the Forssman glycolipid antigen, while strain I cells were Forssman-deficient. Upon finding that strain I cells were contaminated with mycoplasma, we rescued Forssman-deficient cells from strain II using an anti-Forssman plus complement lysis procedure. Clones of surviving cells consisted of two distinct cell types. The first were Forssman-deficient, non-ciliated, spindle-shaped cells which generated negative (apical to basolateral) transepithelial potential differences. Clones of the second type were strongly Forssman-positive, ciliated, and formed island-shaped clusters of cuboidal cells. These latter clones generated positive potential differences and grew more slowly than the spindle-shaped clones. Spindle cells were enriched in fucolipids, while cuboidal cells contained higher levels of sulfated glycolipids. These two types of clones should provide excellent model systems in which to study the processing and polarity of glycolipids in epithelial cells.