title: Enzyme immunoassay for human chorionic gonadotropin using monoclonal antibodies elicited with a synthetic peptide.
abstract: We recently described the generation of mouse monoclonal antibodies directed against hCG using a synthetic peptide immunogen: the carboxy-terminal peptide (CTP) of beta-hCG. The CTP, residues 109-145, is a portion unique to hCG and is not present in other glycoprotein hormones. These monoclonal antibodies react with beta-hCG-CTP and whole hCG but do not react with hLH. In the present study, a two-site sandwich ELISA specific for hCG has been developed using these CTP-induced monoclonal antibodies. Two monoclonal antibodies were paired: beta-hCG-CTP-a6 was immobilized to give a hCG-specific solid phase, and a biotinylated monoclonal antibody against beta-hCG was used as the indicator antibody. This second antibody was introduced during the hCG-capture step because of its agonist effect on hCG-capture by beta-hCG-CTP-a6 solid phase. This ELISA system can detect 2.2 IU/l hCG in a serum-free medium and 10.4 IU/l in a medium containing 20% human serum. We did not observe any cross-reactivity with hLH up to concentrations of 5000 IU/l. The hCG-ELISA correlated well (r = 0.99) with a control RIA in an assay of 78 human sera from healthy males, pregnant or non-pregnant females and from patients with choriocarcinoma, hydatidiform mole, or teratocarcinoma.
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D001769:Blood; D006063:Chorionic Gonadotropin / Q000032:analysis* / Q000276:immunology; D003429:Cross Reactions; D004306:Dose-Response Relationship, Immunologic; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006801:Humans; D009842:Oligopeptides / Q000138:chemical synthesis / Q000276:immunology; D011863:Radioimmunoassay
chemical_list: D000911:Antibodies, Monoclonal; D006063:Chorionic Gonadotropin; D009842:Oligopeptides