Monoclonal antibodies to carcinoembryonic antigen (CEA): characterization and use in a radioimmunoassay for CEA.

Fusion of immune spleen cells of mice immunized with CEA with a mouse myeloma cell line resulted in several hybrid cell lines secreting antibodies to CEA as tested by radio-immunoassay. Four of these were cloned by limiting dilution and large amounts of anti-CEA antibodies were produced by growing the anti-CEA-producing cell clones intraperitoneally in mice and collecting the ascites fluids formed. Ascites fluids containing antibodies with both high and low affinity were obtained. The antibody having the highest affinity was shown to be specific to CEA, whereas one antibody showed cross-reaction with the normal cross-reacting antigen (NCA). The establishment of a competitive-inhibition doubleantibody radio-immunoassad with high sensitivity and specificity using mouse monoclonal antibodies is described.