Galacto-N-biose,Gal-b1,3-GalNAc;Thomsen-Fridenreich antigen;

 2-Acetamido-2-deoxy-3-O-(b-D-galactopyranosyl)-D-galactopyranose; 

 b1-3 Galactosyl-N-acetyl galactosamine; T antigen

2-Acetamido-2-deoxy-3-O-(b-D-galactopyranosyl)-D-galactopyranose (also known as galacto-N-biose, GNB and T antigen) is a β 1-3’ linked disaccharide which is found in the gastrointestinal tract as a core component of mucin. GNB has been shown to have potential to protect against glutamate excitotoxicity, a process in which nerve cells can be damaged or destroyed. GNB, along with lactose-N-biose, are found in human milk but are not metabolised by gut enzymes and are instead broken down to a digestible form by bifidobacteria found in the intestinal systems of infants in a symbiotic process. 

Beta-D-Galp-(1->3)-D-GalpNAc is an amino disaccharide consisting of D-galactopyranose at the non-reducing end joined by a (1->3) glycosidic linkage to N-acetyl-D-galactopyranosamine. It has a role as an epitope. It is a D-Galp-(1->3)-D-GalpNAc, a galactosamine oligosaccharide and an amino disaccharide.

Those proteins recognized by antibodies from serum of animals bearing tumors induced by viruses; these proteins are presumably coded for by the nucleic acids of the same viruses that caused the neoplastic transformation.