Cell-Surface Glycoproteins of Two Sublines of the TA3 Tumor,

Summary

Incubation of cells with proteolytic enzymes, followed by fractionation on chromatographic columns, revealed a glycoprotein material of high molecular weight on the surface of cells of the non-strain-specific TA3-Ha subline of the strain A mouse ascites tumor. This material was not observed in fractions obtained by similar procedures from cells of the strain-specific TA3-St subline. Although the material from TA3-Ha cells strongly inhibited agglutination of NN-specific human erythrocytes by an extract of Vicia graminea seeds, no fractions of demonstrable activity were obtained by proteolysis from TA3-St cells, which suggests the absence of carbohydrate groups of similar structure in material removed from TA3-St cells. Incubation of the 2 sublines with neuraminidase (Vibrio cholerae) removed 2.3 times as much sialic acid per unit surface area from the TA3-Ha cell as from the TA3-St cell. The ratio of N-acetyl-to N-glycolyl-neuraminic acid from the TA3-Ha subline was approximately 13:1 and from the TA3-St about 4:1. The correlation of loss of strain specificity in the TA3-Ha cell with the presence of this unique large-surface glycoprotein suggests that this material may mask surface histocompatibility antigens.