Comparative lectin-binding and agglutination properties of the strain-specific, TA-3-St, and the non-strain-specific, TA3-Ha, murine mammary carcinoma ascites sublines. Further studies of receptors in epiglycanin.

The complex carbohydrates at the cell surfaces of two TA3, murine mammary carcinoma ascites sublines (the strain-specific, TA3-St subline and the nonstrain-specific. TA3-Ha line) were compared by binding studies with 125I-labelled concanavalin A (con A), Ricinis communis agglutinin (RCA), and eel-serum agglutinin (ESA). The TA3-Ha cell bound equal amounts of con A, 1.5-fold more RCA, and 4-fold more ESA than the TA3-St cell. Binding-inhibition studies by these lectins and two others [wheat-germ agglutinin (WGA) and potato lectin (STA)] suggest complementary binding-sites between con A and both RCA and ESA. Quantitative agglutination studies with the five lectins, and inhibition determinations by both neuraminidase-treated and untreated epiglycanin revealed that TA3-St, but not TA3-Ha, cells were agglutinated by con A, and that epiglycanin inhibited this agglutination, as well as the agglutination of rabbit erythrocytes by con A. The presence of a con A receptor on epiglycanin was also suggested by the binding of epiglycanin to con A-Sepharose, and its specific elution with methyl alpha-D-mannopyranoside. TA3-St cells were agglutinated at a 10-15-fold lower concentration of either STA or RCA than TA3-Ha cells, but both cells were agglutinated by the same concentration of WGA and ESA. Inhibition by epiglycanin of agglutination of TA3-St cells by either STA or ESA occurred at a concentration lower than that of TA3-Ha cells, but epiglycanin inhibited RCA agglutination of TA3-Hs cells at a concentration lower than that of TA3-St cells. Epiglycanin, but not asialoepiglycanin, inhibited the agglutination of TA3-Ha cells by WGA.