Targeting of [111In]biocytin to cultured ovarian adenocarcinoma cells using covalent monoclonal antibody—Streptavidin conjugates

Abstract

Three monoclonal antibodies (mAb) directed against the human ovarian adenocarcinoma cell line HEY, were substituted with maleimide and covalently bonded to thiolated streptavidin. The conjugates were separated from unreacted reagents by successive affinity chromatography on protein A—Sepharose and iminobiotin columns. Purified conjugates consisted of an immunoglobulin (Ig) monomer bound to a streptavidin tetramer through a covalent bond between the Ig molecule and one of the streptavidin subunits. The conjugates were able to specifically target [¹¹¹In]biocytin to HEY cells in vitro in the presence of human serum and ascitic fluid from ovarian cancer patients.