Specific Human Chorionic Gonadotropin Research Articles

Monoclonal antibodies to human chorionic gonadotropin (HCG) and their use in two-site binding enzyme immunoassays.

A panel of mouse monoclonal antibodies (MABs) was produced against human chorionic gonadotropin (HCG) and its isolated beta-subunit (beta-HCG). According to their binding specificities the antibodies could be divided into HCG-specific and cross-reactive MABs. The HCG-specific antibodies reacted with antigenic sites on holo-HCG or holo-HCG and beta-HCG, or exclusively with the non-associated beta-HCG chain. The cross-reactive antibodies reacted with either HCG and luteinizing hormone (LH) or with HCG, LH, follicle-stimulating hormone (FSH) and thyroid-stimulating hormone (TSH). According to the binding specificities of the MABs and their reciprocal inhibition detected in two-site binding enzyme immunoassays (EIA), altogether 13 epitopes (including the 3 hidden epitopes detectable only on free non-associated beta-HCG) were distinguished by the antibodies described here. Antibody combinations resulting in most effective and specific HCG- or beta-HCG-determination were used as clinical assays and proved their reliability and correctness for monitoring patients with HCG- and/or beta-HCG-producing tumors before and after therapy.

Pilot Study to Detect Early Pregnancy and Early Fetal Loss

A 6-month pilot study was conducted to investigate the feasibility of detecting early pregnancy and early fetal loss in a population of healthy women. To ascertain early pregnancy, monthly 3-day morning urine specimens were collected during each woman's late luteal phase. A specific human chorionic gonadotropin (hCG)-radioimmunoassay, using antibodies against the unique carboxy-terminal portion of beta-hCG, was used to determine pregnancy as early as 9 days fetal developmental age. Eight pregnancies have been reported on a clinical basis, one of which ended in a spontaneous abortion. This pilot study demonstrated the feasibility of detecting early pregnancy and early fetal loss, and an epidemiological study is now being planned to estimate the rate of fetal loss in a large population to establish a baseline for early pregnancy loss.

Measurement of Human Chorionic Gonadotropin (HCG) Concentrations in Paired Maternal and Cord Sera Using an Assay Specific for the Beta Subunit of HCG

Human chorionic gonadotropin (HCG) concentrations were determined in paired maternal and cord sera using an essay specific for the beta subunit of HCG. The sera of 46 mothers and 46 infants, 24 female and 22 male, were studied. Results were compared to those obtained using a radioimmunoassay for luteinizing-hormone (LH) which cross-reacted with HCG. With either assay system, mean maternal HCG concentrations were lower when the sex of the fetus was male than when the sex of the fetus was female. Mean cord HCG concentrations of male (0.09 +/- 0.02 IU/ml) and female (0.09 +/- 0.04 IU/ml) infants were not different as determined by the beta HCG assay. In contrast, the mean cord serum concentration of HCG was significantly greater (P less than .005) in male infants (0.29 +/- 0.05 IU/ml) than in female infants (0.23 +/- 0.09 IU/ml) as determined by the cross-reacting assay. HCG concentrations were lower in both maternal and cord sera when assayed in the specific HCG system than when assayed in the cross-reacting system. There was a significant correlation (r=.9; P less than .005) between the results obtained with the two assays in both maternal and cord blood. Regardless of the assay system employed, the cord serum concentration of HCG was markedly less than the corresponding maternal serum concentration. There was no correlation between maternal and cord serum HCG concentrations with either assay. These data are in agreement with the results of previous studies employing less specific methodology which indicated that maternal serum HCG concentrations were less when the fetus was male than when it was female. They are also consistent with a placental barrier effect with regard to HCG transfer to the fetus. The difference in results obtained in cord blood with the two assay systems suggests that the newborn male infant secretes more LH and/or alpha LH subunits than the newborn female infant.

A radioimmunoassay which specifically measures human chorionic gonadotropin in the presence of human luteinizing hormone

With antiserum to the β-subunit of human chorionic gonadotropin (HCG), we have developed a radioimmunoassay which selectively measures HCG in samples containing both human pituitary luteinizing hormone (HLH) and HCG. High HLH levels observed in samples obtained at the midcycle peak or from castrate patients do not cause significant inhibition in the specific HCG radioimmunoassay. The sensitivity of the assay is sufficient for distinguishing HCG from follicular and luteal phase HLH levels. This specific HCG radioimmunoassay is ideal for following serum HCG levels in patients under going chemotherapy for HCG-secreting tumors as well as for follow-up of patients after termination of molar pregnancies. In addition, the sensitivity of the assay will permit earlier diagnosis of pregnancy which, in turn, would permit earlier therapeutic intervention if desired.