Previous studies have shown that in addition to the tumor specific site on the carcinoembryonic antigen (CEA), this molecule also contains a blood group A like grouping. To study the A like site on the CEA molecule, a radioimmunoassay was devised in which anti A bodies were coupled to either Sepharose or Sephadex beads. The following observations were made. The monosaccharide, N acetyl D galactosamine was capable of inhibiting the interaction between 125I CEA and a preparation of anti A antibodies. A glycopeptide (GP 1), containing the tumor specific antigenic site of the CEA, which was obtained by the enzymatic degradation of the CEA molecule was capable of binding to anti A antibodies. The ratio, by weight, of GP 1 to N acetyl D galactosamine required to achieve equivalent binding was 10-3 to 10-4 to 1. GP 1 has a molecular weight of about 4000 daltons, and although it contains N acetyl D glucosamine, D mannose, D galactose, and L fucose, the glycopeptide is apparently devoid of N acetyl D galactosamine.
|Original language||English (US)|
|Number of pages||8|
|Journal||Journal of Immunology|
|State||Published - Dec 1 1973|
ASJC Scopus subject areas
- Immunology and Allergy