title: Monoclonal antibodies as reversible equilibrium carriers of radiopharmaceuticals.
abstract: We have prepared monoclonal antibodies (MoAbs) with the specific ability to bind metal chelates such as 111In benzyl EDTA. One, 10, 50 and 100 micrograms MoAb CHA255 Kb = 4 X 10E9 was complexed with 111In BLEDTA II, BLEDTA IV, and benzyl EDTA and injected i.v. in Balb/c mice with KHJJ tumor. The biological half-life by whole body counting was profoundly altered for all three compounds; from minutes to hours with 10 micrograms; to days with 100 micrograms. Tumor uptake increased 50 fold at 24 h with increasing MoAb but satisfactory tumor concentrations (3% per g) and tumor/blood ratios (1.8:1) were obtained with an amount equivalent to 7 mg for a human. Blood level and whole body activity were decreased 30-50% within 3 h or i.v. injection of a "flushing" dose of unlabeled indium benzyl EDTA, increasing tumor/blood ratios to 50:1.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D004492:Edetic Acid; D006207:Half-Life; D007204:Indium / Q000378:metabolism; D007700:Kinetics; D051379:Mice; D008807:Mice, Inbred BALB C; D009374:Neoplasms, Experimental / Q000000981:diagnostic imaging*; D011868:Radioisotopes; D011877:Radionuclide Imaging; D014018:Tissue Distribution
chemical_list: D000911:Antibodies, Monoclonal; D011868:Radioisotopes; D007204:Indium; D004492:Edetic Acid