title: A solid-phase receptor binding assay for 125I-hCG.
abstract: A solid-phase radioligand-receptor assay (RRA) to measure the binding of 125I-labelled human chorionic gonadotropin (125I-hCG) to target cell membranes has been developed. The binding of 125I-hCG to membranes immobilized on the wells of microtitration plates reached a maximum at about 3 hours at 37 degrees C, was saturable, displayed a high affinity (Ka = 2.4 X 10(9) M-1) and was specifically inhibited by unlabelled hCG. In comparison with RRAs carried out with membranes in suspension, the solid-phase RRA is significantly simpler and much faster to perform as it avoids centrifugation or filtration procedures. The solid-phase RRA was adapted profitably to process large numbers of samples at the same time. It proved particularly useful as a screening assay to detect anti-hCG monoclonal antibodies with high inhibitory activity for binding of 125I-hCG to its receptors.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000032:analysis; D002462:Cell Membrane / Q000032:analysis; D006063:Chorionic Gonadotropin / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007457:Iodine Radioisotopes; D008297:Male; D011869:Radioligand Assay / Q000379:methods*; D011974:Receptors, LH / Q000378:metabolism*; D013552:Swine; D013737:Testis / Q000032:analysis
chemical_list: D000911:Antibodies, Monoclonal; D006063:Chorionic Gonadotropin; D007457:Iodine Radioisotopes; D011974:Receptors, LH