Properties and characteristics of an anti-human chorionic gonadotropin monoclonal antibody

Abstract

The product of a hybrid cell clone, P₃W₈₀, obtained as ascites fluid from mouse peritoneal cavity had high titres of anti-human chorionic gonadotropin antibodies e.g. 30 to 40% binding of ¹²⁵I-human chorionic gonadotropin at 10⁷ dilution in a radioimmunoassay. The antiserum SB₆ (raised against β-human chorionic gonadotropin distributed by National Institutes of Health, USA gave similar binding at 5000 dilution in parallel runs. The monoclonal antibody recognized best human chorionic gonadotropin (0.3 mlU of hormone/tube with B/B₀ < 75%), but also bound β and α subunits of human chorionic gonadotropin, 12 and 800 folds lower than human chorionic gonadotropin respectively No binding was observed with carboxy terminal peptides of β-human chorionic gonadotropin ranging from 93 to 145 amino acid residues, indicating the lack of recognition of the C-terminal region. No cross-reaction with human leutinizing hormone was obtained at the physiological surge levels, a significant competition (B/B₀ < 75 %. obtainable only at 60 mlU of LER 960 human leutinizing hormone/ tube. The antibody had heavy chain of IgG₁ and light chain of kappa type. It neutralized the bio-activity of human chorionic gonadotropin bothin vitro and invivo.