Preparation, biodistribution, and dosimetry of super(188)Re-labeled MoAb ior cea1 and its F(ab') sub(2) fragments by avidin-biotin strategy

• Published in: Nuclear medicine and biology 1999-01, Vol.26 (1), p.57-62
• Main Authors: Ferro-Flores, G, Pimentel-Gonzalez, G, Gonzalez-Zavala, MA, De Murphy, CA, Melendez-Alafort, L, Tendilla, JI, Croft, B Y
• Format: Article
• Language: English
• Subjects: avidin; biotin; ethane-1-hydroxy-1,1-diphosphonic acid
• ISSN: 0969-8051
• DOI: 10.1016/S0969-8051(98)00050-X

The biotinylated monoclonal antibody (MoAb) ior cea1 and its F(ab') sub(2) fragments were labeled with Re-188 by combination of avidin-biotin strategy. super(188)Re-MoAb, super(188)Re-MoAb-biotin, super(188)Re-F(ab') sub(2), and super(188)Re-F(ab') sub(2)-biotin preparations were produced for these studies with specific activities of 1.30 plus or minus 0.18 GBq/mg and from instant freeze-dried kit formulations using ethane-1-hydroxy-1,1-diphosphonic acid (EHDP) as a weak competing ligand. There were no significant differences (p > 0.05) between the biodistribution in mice of biotinylated and unbiotinylated super(188)Re-labeled immunoconjugates. When avidin was injected as a chase after injection of super(188)Re-MoAb-biotin or super(188)Re-F(ab') sub(2)-biotin, the blood radioactivity level decreased approximately 75% (cumulated activity) and the effective dose decreased almost 25% with respect to that of the radioimmunoconjugates in which the chase effect was not used. Our results suggest that super(188)Re-labeled biotinylated MoAb ior cea1 and its F(ab') sub(2) fragments prepared by this method are stable complexes in vivo.