title: Radiochemical and radioimmunological data of 99Tcm-anti-CEA labelled by two diverse methods.
abstract: The aim of this study was to make a comparative evaluation of a direct and an indirect method for the labelling of anti-CEA with technetium-99m (99Tcm). With the direct method, disulphide bridges were cleaved by the use of 2-mercaptoethanol as reductant, whereas with the indirect method, the antibody was coupled to 2-iminothiolane. In both cases, a preformed intermediate chelate was used for 99Tcm exchange. The radiochemical and radiobiological behaviour of the 99Tcm-labelled species were studied. Furthermore, the influence of the labelling systems on the integrity of monoclonal antibodies, as well as the ability of 99Tcm-anti-CEA to tag onto human cancer cells, was investigated for the two labelling systems. Both methods showed a high labelling yield and resulted in immunoreactive and stable derivatives. However, detailed electrophoretical and radiochemical data, as well as the cysteine challenge trial, indicated relatively greater stability for the 2-mercaptoethanol reduction procedure.
authors.affiliation: Institute of Radiodiagnostics, National Centre for Scientific Research Demokritos, Aghia Paraskevi Attikis, Greece.
authors.forename: A D
authors.initials: AD
authors.lastname: Varvarigou
authors.forename: S C
authors.initials: SC
authors.lastname: Archimandritis
authors.forename: K
authors.initials: K
authors.lastname: Sekeri-Pataryas
authors.forename: T G
authors.initials: TG
authors.lastname: Sourlingas
authors.forename: G
authors.initials: G
authors.lastname: Sivolapenko
authors.forename: E
authors.initials: E
authors.lastname: Paschali
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D006801:Humans; D007202:Indicators and Reagents; D007553:Isotope Labeling / Q000379:methods; D008297:Male; D051379:Mice; D011863:Radioimmunoassay / Q000379:methods; D013667:Technetium; D014018:Tissue Distribution
chemical_list: D000911:Antibodies, Monoclonal; D002272:Carcinoembryonic Antigen; D007202:Indicators and Reagents; D013667:Technetium