A simple method to determine the immunoreactivity of radiolabelled monoclonal antibodies to the TAG-72 antigen.

A simple method has been developed for determining the immunoreactivity of radiolabelled monoclonal antibodies to the TAG-72 antigen. The method involves binding of a constant small amount of the antibody to increasing concentrations of bovine submaxillary mucin. The immunoreactive fraction (IRF) is then determined by linear extrapolation of binding to infinite antigen excess. Using this assay, the IRF of radioiodinated anti-TAG-72 antibodies ranged from 0.22-0.48.