Radioiodination of Antibodies Adsorbed to Insoluble Antigens

A method for radiolodinating antibody adsorbed to an insoluble antigen was developed. Antifibrin antibody as measured by its adsorption to fibrin was found to be sensitive to iodination. Antifibrin adsorption activity was preserved if iodination was carried out while the antibody was adsorbed to fibrin. Subsequent elution and readsorption showed little loss in activity. A fibrinophilic factor from normal globulin with a relatively high adsorption capacity was insensitive to iodination and was therefore unlike antifibrin antibody. A naturally occurring fibrinophilic protein, readily iodinated and elutable, was disclosed by the technique for labeling insoluble components.