An efficient method for labelling antibodies with 111In.

Using a new method, rabbit IgG and a monoclonal antibody have been conjugated with the chelating agent DTPA. This was accomplished with reaction conditions that should entail lower antibody damage than existing methods. Gel filtration of the 111In-labelled antibody conjugate indicated minimal damage to the antibody and radioimmunoassay showed no significant change in its immunological activity.