title: Iodine-131 and indium-111 labelled avidin and streptavidin for pre-targetted immunoscintigraphy with biotinylated anti-tumour monoclonal antibody.
abstract: Studies have been carried out in mice to examine by gamma camera imaging and dissection analysis the biodistribution of 131I- and 111In-labelled avidin and streptavidin. This has included mice with human tumour xenografts pre-targetted with biotinylated anti-tumour monoclonal antibody. Both iodine-labelled avidin and streptavidin were cleared rapidly from the circulation particularly to kidneys, which showed prolonged retention of the tracer. Similar distribution was seen with 111In-labelled preparations, although here tracer also accumulated in the liver. Radiolabelled preparations could form complexes in vitro with a biotinylated monoclonal antibody. This biotinylated antibody, following radioiodine labelling, localized in xenografts of a human osteosarcoma. When xenografted mice were injected with biotinylated antibody followed by 111In-labelled avidin, levels of tracer per gram of tumour tissue were four times higher than those in non-pretreated mice. However, there was still marked liver and kidney uptake of tracer and, since this dominated the images, tumours were not visualized by scintigraphy.
authors.affiliation: Cancer Research Campaign Laboratories, University of Nottingham, UK.
authors.forename: M V
authors.initials: MV
authors.lastname: Pimm
authors.forename: H F
authors.initials: HF
authors.lastname: Fells
authors.forename: A C
authors.initials: AC
authors.lastname: Perkins
authors.forename: R W
authors.initials: RW
authors.lastname: Baldwin
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D001360:Avidin; D001426:Bacterial Proteins; D001710:Biotin; D007205:Indium Radioisotopes; D007457:Iodine Radioisotopes; D051379:Mice; D009369:Neoplasms / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D019809:Streptavidin
chemical_list: D000911:Antibodies, Monoclonal; D001426:Bacterial Proteins; D007205:Indium Radioisotopes; D007457:Iodine Radioisotopes; D001360:Avidin; D001710:Biotin; D019809:Streptavidin