title: Unmasking of an immunoreactive site on the alpha subunit of human choriogonadotropin bound to the extracellular domain of its receptor.
abstract: To define the human choriogonadotropin (hCG) hormone's contact points with its receptor, we examined five monoclonal anti-hCG antibodies for their binding ability to the hCG-intact receptor complex and to the hCG-truncated extracellular N-terminal half receptor complex. hCG-producing CHO cells were transfected with the N-terminal 297 residues of the porcine LH/CG receptor and the secreted complexes were detected by two-site immunoassays based on anti-receptor and anti-hCG antibodies. Four antibodies did not show any differences toward the two types of complexes. In contrast, a particular antibody, directed to the alpha-subunit of hCG, recognized the hCG-truncated receptor complex but not the hCG-intact receptor complex. These results substantiate recent reports indicating that, if most of the whole alpha/beta dimer is bound to the N-terminal half of the receptor, some regions of the alpha-subunit might be contacting the C-terminal half.
authors.affiliation: Service d'Immunologie Moléculaire, Institut Gustave-Roussy, Villejuif, France.
authors.forename: J
authors.initials: J
authors.lastname: Pantel
authors.forename: J J
authors.initials: JJ
authors.lastname: Remy
authors.forename: R
authors.initials: R
authors.lastname: Salesse
authors.forename: A
authors.initials: A
authors.lastname: Jolivet
authors.forename: J M
authors.initials: JM
authors.lastname: Bidart
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D016466:CHO Cells; D006063:Chorionic Gonadotropin / Q000276:immunology / Q000378:metabolism; D018997:Chorionic Gonadotropin, beta Subunit, Human; D006224:Cricetinae; D000939:Epitopes / Q000032:analysis / Q000378:metabolism; D015292:Glycoprotein Hormones, alpha Subunit / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D008961:Models, Structural; D010446:Peptide Fragments / Q000276:immunology / Q000378:metabolism; D017433:Protein Structure, Secondary; D011863:Radioimmunoassay; D011974:Receptors, LH / Q000096:biosynthesis / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000378:metabolism; D013552:Swine; D014162:Transfection
chemical_list: D000911:Antibodies, Monoclonal; D006063:Chorionic Gonadotropin; D018997:Chorionic Gonadotropin, beta Subunit, Human; D000939:Epitopes; D015292:Glycoprotein Hormones, alpha Subunit; D010446:Peptide Fragments; D011974:Receptors, LH; D011994:Recombinant Proteins