Stabilization of an At-Labeled Antibody with Sodium Ascorbate.

At, an α-particle emitter, has recently attracted attention for radioimmunotherapy of intractable cancers. However, our sodium dodecyl sulfate polyacrylamide gel electrophoresis and flow cytometry analyses revealed that At-labeled immunoconjugates are easily disrupted. Luminol assay revealed that reactive oxygen species generated from radiolysis of water caused the disruption of At-labeled immunoconjugates.

Radioimmunotherapy with an At-labeled anti-tissue factor antibody protected by sodium ascorbate.

Tissue factor (TF), the trigger protein of the extrinsic blood coagulation cascade, is abundantly expressed in various cancers including gastric cancer. Anti-TF monoclonal antibodies (mAbs) capable of targeting cancers have been successfully applied to armed antibodies such as antibody-drug conjugates (ADCs) and molecular imaging probes. We prepared an anti-TF mAb, clone 1084, labeled with astatine-211 ( At), as a promising alpha emitter for cancer treatment.