A new method of technetium-99m labeling of monoclonal antibodies through sugar residues. A study with TAG-72 specific CC-49 antibody.

We have developed a very efficient labeling technique for monoclonal antibodies with technetium-99m. Oxidation of sugar residues on the IgG class of antibodies leads to the generation of aldehyde groups which are further reacted with two newly developed hydrazide compounds. This methodology introduces sulfhydryl groups on the antibody through sugar residues which can be labeled with technetium-99m. We have studied the TAG-72 specific second generation antibody CC-49. The specific activity of the labeled antibody was high without loss of its immunoreactivity.