Preparation of TH227-Labeled Radioimmunoconjugates, Assessment of Serum Stability and Antigen Binding Ability.

In this study, the feasibility of constructing radioimmunoconjugates by using the novel therapeutic candidate alpha-emitter, 227Th, was evaluated. By use of the bifunctional chelator, p-SCN-benzyl-DOTA, 227Th was conjugated to the two monoclonal antibodies, rituximab and trastuzumab. Their stability in 80 fetal bovine serum at 37°C was measured. The immunoreactive fractions were determined by using CD20- and HER2-positive cells, respectively. The overall labeling yield spanned from 6 to 17. The radioimmunoconjugates demonstrated a relevant stability in serum and showed appropriate antigen-binding abilities. [ABSTRACT FROM AUTHOR]