Presence of blood group H antigen on a carcinoembryonic antigen, and its enzymatic modification into blood group A and B specificities.

A carcinoembryonic antigen (CEA-M) was purified from a hepatic metastasis obtained from a blood group O patient with cancer of the rectum. Using 125I-labeled carcinoembryonic antigen (CEA) and blood group antisera, H specificity has been found on the CEA-M. As the addition of anti-H to anti-CEA does not modify the extent of binding of labeled CEA-M to its antibodies (86%), the H and CEA determinants are carried by the same molecule. The affinity chromatography of CEA-M on an immunosorbent "anti-H-Sepharose" demonstrated that a proportion of CEA-M molecules might bear both H and CEA antigenic determinants. In addition, glycosyltransferases were used to modify the blood group H specificity into blood group A or B specificities.