Syntheses of functionalized indium porphyrins for monoclonal antibody labeling.

The syntheses and characterizations of five differently hydrosoluble monosubstituted aryl porphyrins are reported. Their metallation with indium-111 was achieved and provided tracers with strong specific activities. The covalent coupling between indium-111 porphyrins and BSA served as a model reaction for the definition of the best experimental coupling conditions; the transposition to the labeling of anti-CEA monoclonal antibody was realized. The conjugates exhibited an in vitro good mAb-labeling efficiency, as well as a good preservation of immunoreactivity.

Synthesis of a monoclonal antibody-indium-111-porphyrin conjugate.

Antibodies were labelled with indium-111 with a view to their use in the radio-immunodetection of cancers. The covalent coupling between indium-111 porphyrin and monoclonal antibodies (IgG and F(ab')2 fragment) was achieved using the ester activated method [N-hydroxy-succinimide/1-ethyl-3-(3-dimethylaminopropyl)carbodiimide]. After purification, this provided conjugated with specific activities of 6 muCi/micrograms Mab (9.3 molecules per Mab) or 1 muCi/microgram (F(ab')2 fragment (1.5 molecule per F(ab')2). ELISA procedures suggested the full retention of immunoreactivity by the radiolabelled antibodies.