Synthesis and evaluation of radioiodinated iodophenyl-bromoacetamides and iodoanilines as potential antibody radioimmunoconjugates

Direct radioiodination of monoclonal antibodies using oxidants such as chloramine T presumably labels the phenyl group of tyrosine residues of antibodies. In an effort to overcome the problem of in vivo deiodination which occurs as a consequence of hydrolytic and enzymatic processes, we have designed and synthesized two non-phenolic reagents: (1) N-(m-[125/131I]iodophenyl) bromoacetamide which reacts with free amino groups of antibodies, and (2) m-[125/131I]iodoaniline which reacts via the oxidized oligosaccharide moieties on the F region. The multistep syntheses of both reagents and their conjugation to monoclonal antibody Lym-1 (IgG2a) will be described. Comparative biological evaluation of the radioiodinated immunoconjugates will also be presented