Immunological considerations in the use of goat antibodies to carcinoembryonic antigen for the radioimmunodetection of cancer.

Preparation of radioantibodies from carcinoembryonic antigen (CEA) antisera raised in goats by conventional procedures necessitates extensive absorption procedures to remove antibody activity against CEA-related substances. Further purification by affinity chromatography increases the antibody content of the radiolabeled preparation and enhances antibody uptake by a xenogeneic tumor. In patients given injections of CEA radioantibody, immune complexes form with CEA or a human antibody reactive with goat gamma-globulin, but these complexes do not appear to prevent tumor radioimmunodetection. Monoclonal antitumor antibodies from appropriate animal species would be a more suitable source, eliminating many of the problems encountered with conventional antisera.