Labelling monoclonal antibody 10D9 with 125I using the iodogen method

To establish the method radiolabeled monoclonal antibody 10D9 against human costimulatory molecules CD80 with 125I, 10D9 was labeled with 125I using the Iodogen method at room temperature. The labeling efficiency and radiochemical purity were tested with TCA, and the immune activity and stability of the labeling product were analyzed. The optimum labeling condition was 10 μg Iodogen, 20 μg 10D9 and 22.2 MBq Na125I. The reaction time was 8 min at room temperature. The labeled yield was (84.10±3.18)%, and the radiochemical purity was (98.49±1.14)%. The radio-activity of 125I-10D9 was 933.51 MBq/mg. The specific binding efficiency of 125I-10D9 with Daudi cell was(23.21±1.14)%. The radiochemical purity of 125I-10D9 was over 90% after three weeks of mixing with PBS. In conclusion, the method is simple and easy to perform. The labeling efficiency and radiochemical purity is high. The stability of 125I-10D9 is fine in vitro and 125I-10D9 keeps its immune activity after Iodogen labeling. (authors)