Characterization of a monoclonal antibody inhibiting the biological activity of human chorionic gonadotrophin.
A mouse monoclonal antibody (MCA), raised against human chorionic gonadotrophin (HCG) and coded 130A, was characterized with several types of immunoassay and with in-vitro and in-vivo bioassays. MCA 130A binds strongly to the intact HCG molecule but less so to either alpha- or beta-subunit; The dissociation constant of the MCA-HCG complex was found to be in the order of 70 pmol/l. MCA 130A inhibits the biological activity of HCG very effectively, both in vitro and in vivo. In a competitive immunoassay MCA 130A binds 30 x better to HCG than to human luteinizing hormone (HLH). The selectivity in the bioassays was much higher, e.g. in vitro, 50% inhibition of HLH-stimulated testosterone production requires 2600 x as much MCA as is needed for inhibiting HCG-stimulated production. Possible reasons for this difference in selectivity are discussed.
Kloosterboer
H
H
Organon Scientific Development Group, Oss, The Netherlands.
Hahlin
M
M
Schuurs
A
A
D000818:Animals; D000911:Antibodies, Monoclonal / Q000032:analysis*; D001681:Biological Assay; D006063:Chorionic Gonadotropin / Q000037:antagonists & inhibitors* / Q000276:immunology; D006801:Humans; D007124:Immunoenzyme Techniques; D007986:Luteinizing Hormone / Q000037:antagonists & inhibitors* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D011863:Radioimmunoassay
D000911:Antibodies, Monoclonal; D006063:Chorionic Gonadotropin; D007986:Luteinizing Hormone