Baboon anti‐idiotype antibodies mimic a carcinoembryonic antigen epitope

A baboon was immunized with NP-4, a murine monoclonal antibody (MAb) to carcinoembryonic antigen (CEA). Anti-idiotype antibodies were purified from the baboon serum by affinity chromatography on a NP-4-coupled matrix, followed by adsorption of the non-specific antibodies on an irrelevant MAb. Baboon anti-idiotype antibodies inhibited specifically the binding between NP-4 and CEA. Mice immunized with baboon anti-idiotype antibodies produced antibodies to the CEA epitope recognized by NP-4. These results indicate that baboon anti-idiotype antibodies functionally mimic a CEA epitope and that they can be suitable for idiotype therapy of human CEA-producing carcinomas.