Abstract
AH109A tumor cell agglutinations caused by Rana catesbeiana agglutinin and Rana japonica agglutinin were inhibited by urinary glycoproteins and glycopeptides from cancer-bearing and normal rats. Fractions of a series of substances (molecular weight above 10000) from cancer-bearing rat urine (10T) and from normal rat urine (N10T) inhibited cytoagglutination caused by Rana catesbeiana agglutinin and by Rana japonica agglutinin, while other fractions (ranging in molecular weight from 1000 to 10000) from cancer-bearing rat urine (01T), and from normal rat urine (N01T) only inhibited that caused by Rana catesbeiana agglutinin. It is probable that these two agglutinins recognize different AH109A cell surface sialoglycoconjugates. Since the content of sialic acid of each fraction is independent of its inhibitory capacity, these agglutinins seem to recognize a certain sialoglycoconjugate, regardless of the content of sialosyl residues.