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 the 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 metabolized 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.