Radiolabeling, Biodistribution, and Dosimetry of 123I-mAb 14C5: A New mAb for Radioimmunodetection of Tumor Growth and Metastasis In Vivo

This study reports on the in vitro evaluation, biodistribution, and dosimetry of 123I-labeled monoclonal antibody (mAb) 14C5, a new antibody-based agent proposed for radioimmunodetection of tumor growth and metastasis in vivo. Methods: 123I-mAb 14C5 was prepared by direct iodination and tested for stability in vitro. Binding assays were performed on human SK-BR-3 and HeLa carcinoma cells to investigate the antigen expression, antibody affinity, and kinetics of tracer binding. For the biodis-tribution and dosimetry study, 3- to 4-wk-old NMRI mice were injected intravenously with 123I-mAb 14C5 (148.0 7.4 kBq per mouse) and killed at preset time intervals. Organs, blood, urine, and feces were counted for radioactivity uptake, and the data were expressed as the percentage injected dose per gram tissue (%ID/g tissue) or %ID. The MIRDOSE3.0 program was applied to extrapolate the estimated absorbed radiation dose