Isolation and partial characterization of an epiglycanin-like glycoprotein from a new non-strain-specific subline of TA3 murine mammary adenocarcinoma

Abstract

A new non-strain-specific ascites subline of the TA3 mammary adenocarcinoma TA3-MM, which arose in vivo from the strain-specific TA3-St subline during an acute respiratory illness of the syngeneic mouse strain A/HeHa hosts, possessed at its surface a glycoprotein not found on the parent TA3-St cell. This glycoprotein, termed TA3-MM epiglycanin, was characterized by a high molecular weight (500,000), by potent inhibition of hemagglutination by the Vicia gramines lectin, and by carbohydrate and amino acid compositions nearly identical to those of the glycoprotein epiglycanin present at the surface of the allotransplantable TA3-Ha ascites cell. By electron microscopic examination, TA3-MM epiglycanin appeared as long extended rods with widths (2.5 nm) and lengths (450--500 nm) similar to those of TA3-Ha epiglycanin. Incubation of each of two sublines of the TA3-MM ascites cell, TA3-MM/1 and TA3-MM/2, with a modified trypsin followed by column chromatography produced approximately 1.0- and 0.2-fold as much epiglycanin-like material, respectively, as was obtained from the TA3--a ascites cell. Continuous growth of the TA3-MM cell in suspension culture resulted in an almost complete disappearance of epiglycanin in a manner demonstrated earlier for the TA3-Ha cell grown under similar conditions. Allotransplantability in the TA3-MM cell may be due, at least in part, to masking a histocompatibility antigens by epiglycanin-like molecules.