The evaluation of 186Re-labeled antibodies using N2S4 chelate in vitro and in vivo using tumor-bearing nude mice

We have recently described a method for radiolabeling monoclonal antibodies, with metallic radionuclides using a new chelating agent N₂S₃. Using this chelate the monoclonal antibodies Lym-1 and B72.3 were labeled with ¹⁸⁶Re and their biological integrity was evaluated in vitro and in vivo. ¹⁸⁶Re-labeled antibodies using N₂S₄ methodology were found to be stable in human serum and retained their immunoreactivity. Intravenous administration of 0.5 mCi ¹⁸⁶Re-labeled antibodies resulted in partial or complete regression of tumor tissue in mice.