We report the successful labeling of mouse IgG with yttrium-90 (Y-90) using isothiocyanatobenzyl-ethylenediaminetetraacetic acid (SCN-Bz-EDTA) as a chelating agent and compared the result with labeling by indium-111 (In-111). After conjugating IgG with SCN-Bz-EDTA, a predetermined volume of conjugated IgG was mixed with different volumes of either Y-90 or In-111 acetate and incubated at 37℃. Labeling efficiency was assessed at specific intervals upto 3 hr. After 3 hr, the mixtures were challenged with Na2EDTA to evaluate the transchelation of labeled Y-90 or In-111. All mixtures showed labeling efficiency of around 50% with Y-90 and the leveling was fairly preserved even after Na2EDTA challenge. However, labeling with In-111 was unsuccessful when conjugated IgG was not separated from the unconjugated form. When separated, however, In-111 showed more than 80% labeling efficiency though labeling with In-111 could not tolerate Na2EDTA challenge. In conclusion, IgG was efficiently labeled by Y-90 using SCN-Bz-EDTA though labeling with In-111 showed some problems associated with this method.journal articl
