Radio-iodination of monoclonal antibody using potassium [125I]-(4-isothiocyanatobenzylammonio)-iodo-decahydro-closo-dodecaborate (iodo-DABI).

BACKGROUND Negatively-charged polyhedral boron clusters can be easily halogenated with highly stable boron-halogen bonds and are promising in radionuclide diagnostics and cancer therapy. MATERIALS AND METHODS The radio-iodination conditions for the closo-dodecaborate anion and for the conjugation of its labeled isothiocyanatobenzylammonio derivative to the monoclonal antibody (mAb) were optimized. RESULTS The labeling yield was about 90% and the overall conjugation yield was 55-60%. The in vitro stability of the radio-iodinated mAb was good under physiological and non-physiological conditions. The immunoreactivity of the labeled mAb (SK-BR-3 cells) was retained in the one-pot two-step labeling. CONCLUSION Negatively-charged polyhedral boron clusters can be used for indirect radio-iodination of mAbs.