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Spontaneously transformed highly tumorigenic AL/N strain mouse cells and their SV40 virus transformed clonal derivatives were compared. Glycoproteins were labeled by various metabolic precursors (amino acids, glucosamine, mannosamine, etc.). The flow of such labels into various subcellular components was followed. Cell surface membranes were obtained and the components of these membranes were separated by polyacrylamide gel electrophoresis. The biosynthesis of a prominent glycoprotein component with an apparent molecular weight of 180 K dalton was reduced in the SV40 transformed cells, when all the different kinds of cells were grown in their logarithmic phase. Three types of SV40 specific antigens were detected by immunologic assays: (1) T antigens, (2) tumor specific surface antigens (TSSA), and (3) tumor specific transplantation antigens (TSTA). A rapid and sensitive microassay for TSSA guided the development of a mild and efficient detergent (Triton X-100) solubilization technique, and the purification of the antigens that appear to co-purify in various procedures. The antigens expressed on the cell surface that are responsible for immunologic recognition and rejection of the SV40 transformed cells represented a very minor fraction of the cell surface membrane components. The microassay for TSSA allowed partial purification and characterization of the SV40 specific cell surface antigen (s). The(se) SV40 specific cell surface antigen (s) in the AL/N strain mouse functionally opposes cellular tumorigenicity.

Publisher Summary This chapter discusses a study in which the biosynthesis of glycoconjugates in cell culture of a closely related family of AL/N mouse embryo clones were monitored by anion-exchange chromatography of glucosamine-labeled macromolecules. In the study, four clones were studied, the parent clone and three subclones obtained by recloning 1 h after infection by simian virus 40. Of the subclones, two were transformed, as defined by the presence of viral specific nuclear T antigen; the third was T antigen negative. Cell cultures were divided into three compartments: the medium, the trypsinate, and the cells. The compartments were prepared for anion-exchange chromatography by papain digestion, followed by dialysis to equilibrium against the initial column buffer. The ion-exchange profiles of all three compartments of the T antigen negative subclone were similar to those of the parent clone. In each compartment, seven peaks were detected. The first four appeared to be glycopeptides, and the last three glycosaminoglycans.

Publisher Summary This chapter discusses glycolipids in SV40 and polyoma virus-transformed mouse cell lines. In a study described in the chapter, various normal, spontaneously transformed, and DNA tumor virus-transformed mouse cell lines were grown in tissue culture and were analyzed for changes in ganglioside composition. The cell lines included the highly contact inhibited mouse fibroblasts 3T3, its SV40 and polyoma doubly transformed variant SVPY 3T3; an established epithelial-like normal cell line from inbred mouse N AL/N; its spontaneously transformed tumorigenic variant T AL/NT; and its SV40-transformed SVS AL/N and polyoma transformed PY AL/N variants. The decrease in the virus-transformed variants in N-acetylneuraminyl-galactosyl-N-acetylgalactosaminyl-(N-acetylneuranrinyl)-galactosyl-glucosylceramide and galactosyl-N-acetylgalactosaminyl-(N-acetylneuraminyl)-galactosylglucosylceramide occured consistently, irrespective of the growth medium, the substratum, the growth conditions, and the harvesting conditions.