Carcinoembryonic antigen-like substances of human bile. Isolation and partial characterization

Three species of carcinoembryonic antigen (CEA)-like macromolecules, called the biliary glycoprotein I, II and III (BGP I, II and III) were identified in human bile. BGP I was found in normal gall-bladder bile and hepatic bile but not in bile subjected to inflammation ("white bile"). It was immunologically related to CEA and NGP (the "normal CEA-like glycoprotein". Synonyms: NCA, CCEA-2, etc.). BGP I differed immunologically from CEA in that it lacked the tumor-associated determinants of CEA. It was different from NGP (and CEA) in that it contained BGP I specific determinants as revealed by anti-BGP I antibodies. In bile from gallbladders with obstructed outlet and subjected to cholecystitis, a non-malignant inflammatory process, BGP I was replaced by BGP II and BGP III. Immunologically and physicochemically, BGP II and BGP III appeared to be closely similar to NGP and CEA, respectively.