Labeling of antibodies with 64Cu using a conjugate containing a macrocyclic amine chelating agent

The conjugation of a model antibody (rabbit-anti-HSA-IgG) with a functionalized derivative of cyclam (1-(3-aminopropyl)-4-methyl-1,4,8,11-tetraazacyclotetradecane) is reported. Coupling of this derivative to the antibodies was accomplished using commercially available heterobifunctional coupling agents. The conjugation technique produced minimal effects on the antibody binding activity. 64Cu complexes with this cyclam derivative have excellent stability in human serum and aqueous solutions containing 1 mM EDTA. The high stability of these Cu-complexes suggests that this system, or other analogous systems, may be useful for production of stable 67Cu-immunotherapeutic agents.