Immunohistologic distribution of CEA defined by human anti‐CEA antibody in the serum of a colonic cancer patient

Abstract

The serum from a colonic cancer patient was examined showing anti‐CEA (carcinoembryonic antigen) activity but not anti‐NCA (nonspecific cross‐reacting antigen) activity. Conventional immunoelectrophoresis and radioimmunoelectrophoresis in conjunction with iodine 125‐labeled CEA strongly suggested that this serum contained M‐protein (IgG kappa). Most of the anti‐CEA activity was found in the M‐component using radioimmunoelectrophoresis, suggesting the monoclonal nature of anti‐CEA autoantibodies. With the use of this serum the histologic distribution of the antigen by the immunoperoxidase method was demonstrated for the first time. Anti‐CEA specificity of this serum was confirmed by the fact that the absorbed antibody with purified CEA gave negative staining of the serial sections of the tissues that formerly had immunostaining. Interestingly, this distribution was almost superimposed on that detected by the murine monoclonal anti‐CEA antibody AS802. The data suggested that the antibody in the serum reacted with the CEA molecule in the tissue sections, the majority of which were found in the cancerous tissues. Copyright © 1985 American Cancer Society