A standard hybridoma fusion technique was used to produce a monoclonal antibody capable of binding both carcinoembryonic antigen (CEA) and the hapten 4-amino-phthalate. A hypoxanthine-aminopterin-thymidine (HAT) sensitive anti-CEA hybridoma and KLH-phthalate immunized spleen cells were hybridized to yield clones producing bispecific monoclonal antibodies. The desired bispecific antibody was identified using both enzyme-linked immunosorbent assay (ELISA) and radio-immunoassay. The resultant hybrid-hybridoma or "tridoma" was subcloned and expanded to yield a stable population. Bifunctional antibody was then isolated from the various possible recombinants by ion exchange chromatography. This general method may be used to produce bispecific monoclonals against a wide variety of tumor associative antigens and reagents for immunodetection or treatment.
