Anti-GP2 antibodies are used in the immunodetection of the protein glycoprotein 2. In humans, the canonical protein has a reported length of 537 amino acid residues and a mass of 59.5 kDa. Its subcellular localization is in the cell membrane and is secreted. Up to 4 different isoforms have been reported for this protein. It is notably expressed in the pancreas. GP2 is known to function as a intestinal M-cell transcytotic receptor specific for type-I-piliated bacteria that participates in the mucosal immune response toward these bacteria. Post-translational modifications have been described, including N-glycosylation. Synonyms for this target antigen include pancreatic secretory granule membrane major glycoprotein GP2, glycoprotein 2 (zymogen granule membrane), pancreatic zymogen granule membrane associated protein GP2, and ZAP75. GP2 gene orthologs have been reported in the mouse, rat, bovine and chimpanzee species.