DETECTION OF CANCER AND ABNORMAL PREGNANCY USING MONOCLONAL ANTIBODIES SPECIFIC FOR HCG ISOFORMS

摘要

Human chorionic gonadotropin (hCG) exists in blood and urine as a variety of isoforms, one of which contains peptide bond cleavages within its beta subunit and is referred to as nicked hCG (hCGn). This hCGn isoform appears more prevalent in the urine of patients with certain malignancies and possibly in other diseases of pregnancy. The present invention is directed to two monoclonal antibodies to an isoform of hCGn isolated from a choriocarcinoma patient. Two-site immunometric assays have been developed using these antibodies, designated B151 and B152. The former exhibits good specificity for hCGn independent of the source of the hCGn, that form excreted by choriocarcinoma patients, or the form of hCGn from normal pregnancies. The latter antibody, B152, is uniquely sensitive to the carbohydrate moieties of choriocarcinoma hCG, nicked or non-nicked, since its recognition of ligand is dependent upon carbohydrate differences rather than differences in peptide bond. These two immunometric assays provide novel diagnostic tools based on direct measurement of these hCG isoforms.