L Aldaz-Carroll1, S Richon2, V Dangles-Marie3, M Cocquebert4, T Fournier5, F Troalen6, D Stevens7, B Guery8, A-M Hersant9, J Guibourdenche10, A Nordor11, A Pecking12, D Bellet13. 1. Université Paris Descartes, Sorbonne Paris Cité, Unité de Technologies Chimiques et Biologiques pour la Santé, Faculté de Pharmacie, 4, avenue de l'Observatoire, 75006 Paris France; Ecole Nationale Supérieure de Chimie de Paris, Chimie Paristech, 11, rue Pierre et Marie Curie, 75005 Paris France; CNRS, UMR8258, 4, avenue de l'Observatoire, 75006 Paris France; INSERM U1022, 4, avenue de l'Observatoire, 75006 Paris France. Electronic address: lydia.aldaz-carroll@parisdescartes.fr. 2. Université Paris Descartes, Sorbonne Paris Cité, Institut Médicament Toxicologie Chimie Environnement (IMTCE), 4, avenue de l'Observatoire, 75006 Paris France. Electronic address: sophie.richon@parisdescartes.fr. 3. Université Paris Descartes, Sorbonne Paris Cité, 4, avenue de l'Observatoire, 75006 Paris France; Centre de recherche Institut Curie, Recherche Translationnelle, 26 rue d'Ulm, 75005 Paris France. Electronic address: Virginie.Dangles-Marie@curie.fr. 4. Université Paris Descartes, Sorbonne Paris Cité, UMR-S 1139, 4, avenue de l'Observatoire, 75006 Paris France; INSERM U1139, 4, avenue de l'Observatoire, 75006 Paris France; PremUP fundation, Maternité de Port Royal, 53 avenue de l'Observatoire, 75014 Paris France. Electronic address: melanie.cocquebert@gmail.com. 5. Université Paris Descartes, Sorbonne Paris Cité, UMR-S 1139, 4, avenue de l'Observatoire, 75006 Paris France; INSERM U1139, 4, avenue de l'Observatoire, 75006 Paris France; PremUP fundation, Maternité de Port Royal, 53 avenue de l'Observatoire, 75014 Paris France. Electronic address: thierry.fournier@parisdescartes.fr. 6. Institut de Cancérologie Gustave-Roussy, Département de Biologie et Pathologie Médicales, 114 rue Édouard-Vaillant, 94805 Villejuif Cedex, France. Electronic address: frederic.troalen@gustaveroussy.fr. 7. Institut Curie, Hôpital René Huguenin, Département de santé publique, 35, rue Dailly, 92210 Saint Cloud, France. Electronic address: denise.stevens@curie.fr. 8. Institut Curie, Hôpital René Huguenin, Laboratoire d'Oncobiologie, Département de Biopathologie, 35, rue Dailly, 92210 Saint Cloud, France. Electronic address: beatrice.guery@curie.fr. 9. Institut Curie, Hôpital René Huguenin, Laboratoire d'Oncobiologie, Département de Biopathologie, 35, rue Dailly, 92210 Saint Cloud, France. Electronic address: hersant@club-internet.fr. 10. Université Paris Descartes, Sorbonne Paris Cité, UMR-S 1139, 4, avenue de l'Observatoire, 75006 Paris France; INSERM U1139, 4, avenue de l'Observatoire, 75006 Paris France; PremUP fundation, Maternité de Port Royal, 53 avenue de l'Observatoire, 75014 Paris France. Electronic address: jean.guibourdenche@parisdescartes.fr. 11. Université Paris Descartes, Sorbonne Paris Cité, 4, avenue de l'Observatoire, 75006 Paris France; Centre de recherche Institut Curie, Recherche Translationnelle, 26 rue d'Ulm, 75005 Paris France. Electronic address: akpeli.nordor@gmail.com. 12. Institut Curie, Hôpital René Huguenin, Laboratoire d'Oncobiologie, Département de Biopathologie, 35, rue Dailly, 92210 Saint Cloud, France. Electronic address: alain.pecking@orange.fr. 13. Université Paris Descartes, Sorbonne Paris Cité, Unité de Technologies Chimiques et Biologiques pour la Santé, Faculté de Pharmacie, 4, avenue de l'Observatoire, 75006 Paris France; Ecole Nationale Supérieure de Chimie de Paris, Chimie Paristech, 11, rue Pierre et Marie Curie, 75005 Paris France; CNRS, UMR8258, 4, avenue de l'Observatoire, 75006 Paris France; INSERM U1022, 4, avenue de l'Observatoire, 75006 Paris France; Institut Curie, Hôpital René Huguenin, Laboratoire d'Oncobiologie, Département de Biopathologie, 35, rue Dailly, 92210 Saint Cloud, France. Electronic address: dominique.bellet@parisdescartes.fr.
Abstract
BACKGROUND: The sequence of the beta-subunit of human chorionic gonadotropin (hCGβ) varies depending on whether hCGβ is encoded by type I or type II genes. Type II genes are upregulated in trophoblast and cancer but hCGβ can be detected in the serum of nonpregnant women and healthy individuals. We aimed to determine whether monoclonal antibody (mAb) FBT11-II specifically detects hCGβ encoded by type II genes (type II hCGβ). METHODS: Competitive inhibition assays with synthetic peptides, immunocytochemical and immunohistochemical studies, type II hCGβ dosing immunoassays and sequencing of CGB genes were performed. RESULTS: Competitive inhibition assays determined that mAb FBT11-II recognizes the type II hCGβ derived peptide. CGB mRNA sequencing of JEG-3 (trophoblastic) and T24 (bladder) cell lines confirmed that JEG-3 expresses type II genes while T24 expresses exclusively type I. FBT11-II only recognizes JEG-expressed hCGβ. Placenta immunohistochemical studies confirmed that type II hCGβ expression is restricted to the syncytiotrophoblast. Immunoassays detected type II hCGβ in serum of patients with either nontrophoblastic cancers or fetal Down syndrome. CONCLUSION: Type II gene expression can be detected using FBT11-II. This specific recognition could improve the clinical usefulness of assays aimed at either managing aggressive tumors or screening for Down syndrome.
BACKGROUND: The sequence of the beta-subunit of human chorionic gonadotropin (hCGβ) varies depending on whether hCGβ is encoded by type I or type II genes. Type II genes are upregulated in trophoblast and cancer but hCGβ can be detected in the serum of nonpregnant women and healthy individuals. We aimed to determine whether monoclonal antibody (mAb) FBT11-II specifically detects hCGβ encoded by type II genes (type II hCGβ). METHODS: Competitive inhibition assays with synthetic peptides, immunocytochemical and immunohistochemical studies, type II hCGβ dosing immunoassays and sequencing of CGB genes were performed. RESULTS: Competitive inhibition assays determined that mAb FBT11-II recognizes the type II hCGβ derived peptide. CGB mRNA sequencing of JEG-3 (trophoblastic) and T24 (bladder) cell lines confirmed that JEG-3 expresses type II genes while T24 expresses exclusively type I. FBT11-II only recognizes JEG-expressed hCGβ. Placenta immunohistochemical studies confirmed that type II hCGβ expression is restricted to the syncytiotrophoblast. Immunoassays detected type II hCGβ in serum of patients with either nontrophoblastic cancers or fetal Down syndrome. CONCLUSION: Type II gene expression can be detected using FBT11-II. This specific recognition could improve the clinical usefulness of assays aimed at either managing aggressive tumors or screening for Down syndrome.