Investigation into the occurrence and structure of lectin receptors on human and bovine erythrocytes milk fat globule and lymphocyte plasma-membrane glycoproteins.

The reduced disaccharide beta-D-galactosyl(1-3)-N-acetyl-D-galactosaminitol was released, after alkaline borohydride and neuraminidase treatment, from human and bovine erythrocyte membrane and fat globule membrane glycoproteins as well as from human and bovine lymphocyte plasma membranes. This disaccharide was found to be substituted to different extents by sialic acid in the various fractions. beta-D-Galactosyl(1-3)-N-acetyl-D-galactosamine is the immunodominant disaccharide of the Thomsen-Friedenreich antigen (TF) and was detected serologically using specific lectins and antibody-containing sera. Bovine fat globule membrane glycoproteins were the only source of Tn antigen. The Tn antigen was detected by anti-Tn-containing sera and by the lectins from Salvia sclarea and Helix pomatiea as well as gas chromatographic detection of N-acetylgalactosaminitol after alkaline borohydride treatment of the native glycoproteins. Human milk fat globule membrane glycoproteins showed the presence of blood group A substance by reaction with rabbit anti-A serum.