title: Monoclonal antibodies for specific cell labeling: considerations, preparations and preliminary evaluation.
abstract: Two types of monoclonal antibodies (MAb), B79.7 and B59.2 determined to be specific for human platelet glycoprotein III.a and III.a.II.b respectively, were labeled with 125I and 111In via diethylenetriaminepentaacetic acid (DTPA) bifunctional chelation technique and evaluated as agents for labeling platelets. Under the chemical conditions chosen one DTPA molecule was bound to one MAb molecule. The specific activities of 111In and 125I preparation averaged 5 and 2.5 Ci/mumol respectively. Both agents showed saturable binding to human platelets. Scatchard analysis showed that the Kd values for 111In-B79.7 and 125I-B79.7 were 83.3 X 10(-9) M and 113.3 X 10(-9) M respectively. The corresponding protein molecules bound per human platelet were 16.75 X 10(3) and 29.5 X 10(3). The Mab B59.2 also reacted with canine platelets and at 50% antigen saturation 49.5% of the added 111In-DTPA-B59.2 was bound to platelets. Using these platelets experimental thrombi were imaged. At 2 h post injection, the thrombi to blood ratios were 15.8. These radiolabeled MAbs are worthy of further evaluation.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000302:isolation & purification; D001792:Blood Platelets / Q000276:immunology*; D004285:Dogs; D005260:Female; D006023:Glycoproteins / Q000097:blood / Q000276:immunology; D006801:Humans; D007204:Indium; D007457:Iodine Radioisotopes; D007700:Kinetics; D004369:Pentetic Acid; D011877:Radionuclide Imaging; D013924:Thrombophlebitis / Q000000981:diagnostic imaging
chemical_list: D000911:Antibodies, Monoclonal; D006023:Glycoproteins; D007457:Iodine Radioisotopes; D007204:Indium; D004369:Pentetic Acid