Carbohydrate determinants associated with carcinoembryonic antigen (CEA).

The reactivities of eight purified preparations of carcinoembryonic antigen with monoclonal antibodies directed to tumor-associated carbohydrate determinants have been studied. All eight preparations showed strong reactivities with AH6, which defines Y structure (Fuc alpha 1----2Gal beta 1----4Fuc alpha 1----3 GlcNAc beta 1----R), whereas only a few preparations showed reactivity with FH4-defining dimeric X determinants, (Gal beta 1----4 Fuc alpha 1----3GlcNAc beta 1----3Gal beta 1----4 Fuc alpha 1----3GlcNA beta 1----3Gal beta 1----R). No other antibodies tested showed any reactivity with these preparations. These carbohydrate markers associated with carcinoembryonic antigen will be useful to enhance the diagnostic value of the antigen.