title: A novel monoclonal antibody to a defined peptide epitope in MUC16.
abstract: The MUC16 mucin is overexpressed and aberrantly glycosylated in ovarian carcinomas. Immunodetection of circulating MUC16 is one of the most used cancer biomarker assays, but existing antibodies to MUC16 fail to distinguish normal and aberrant cancer glycoforms. Although all antibodies react with the tandem-repeat region, their epitopes appear to be conformational dependent and not definable by a short peptide. Aberrant glycoforms of MUC16 may constitute promising targets for diagnostic and immunotherapeutic intervention, and it is important to develop well-defined immunogens for induction of potent MUC16 immunity. Here, we developed a MUC16 vaccine based on a 1.7TR (264 aa) expressed in Escherichia coli and in vitro enzymatically glycosylated to generate the aberrant cancer-associated glycoform Tn. This vaccine elicited a potent serum IgG response in mice and we identified two major immunodominant linear peptide epitopes within the tandem repeat. We developed one monoclonal antibody, 5E11, reactive with a minimum epitope with the sequence FNTTER. This sequence contains potential N- and O-glycosylation sites and, interestingly, glycosylation blocked binding of 5E11. In immunochemistry of ovarian benign and cancer lesions, 5E11 showed similar reactivity as traditional MUC16 antibodies, suggesting that the epitope is not efficiently glycosylated. The study provides a vaccine design and immunodominant MUC16 TR epitopes.
authors.affiliation: Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IPATIMUP, Institute of Molecular Pathology and Immunology, University of Porto, Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal Faculty of Medicine, University of Porto, Porto, Portugal.
authors.forename: Lara
authors.initials: L
authors.lastname: Marcos-Silva
authors.affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IPATIMUP, Institute of Molecular Pathology and Immunology, University of Porto, Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal.
authors.forename: Sara
authors.initials: S
authors.lastname: Ricardo
authors.affiliation: Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
authors.forename: Kowa
authors.initials: K
authors.lastname: Chen
authors.affiliation: Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
authors.forename: Ola
authors.initials: O
authors.lastname: Blixt
authors.affiliation: Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
authors.forename: Emma
authors.initials: E
authors.lastname: Arigi
authors.affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IPATIMUP, Institute of Molecular Pathology and Immunology, University of Porto, Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal.
authors.forename: Daniela
authors.initials: D
authors.lastname: Pereira
authors.affiliation: Department of Pathology, Herlev Hospital, University of Copenhagen, Herlev, Denmark.
authors.forename: Estrid
authors.initials: E
authors.lastname: Høgdall
authors.affiliation: Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
authors.forename: Ulla
authors.initials: U
authors.lastname: Mandel
authors.affiliation: Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
authors.forename: Eric P
authors.initials: EP
authors.lastname: Bennett
authors.affiliation: Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark.
authors.forename: Sergey Y
authors.initials: SY
authors.lastname: Vakhrushev
authors.affiliation: Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal IPATIMUP, Institute of Molecular Pathology and Immunology, University of Porto, Rua Dr. Roberto Frias s/n, 4200-465 Porto, Portugal Faculty of Medicine, University of Porto, Porto, Portugal ldavid@ipatimup.pt hclau@sund.ku.dk.
authors.forename: Leonor
authors.initials: L
authors.lastname: David
authors.affiliation: Copenhagen Center for Glycomics, Department of Cellular and Molecular Medicine and School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Blegdamsvej 3, DK-2200 Copenhagen N, Denmark The Novo Nordisk Foundation Center for Biosustainability, Technical University of Denmark, Hørsholm, Denmark ldavid@ipatimup.pt hclau@sund.ku.dk.
authors.forename: Henrik
authors.initials: H
authors.lastname: Clausen
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D058846:Antibodies, Monoclonal, Murine-Derived / Q000737:chemistry / Q000276:immunology*; D018394:CA-125 Antigen / Q000737:chemistry / Q000276:immunology*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D000939:Epitopes / Q000737:chemistry / Q000276:immunology*; D005260:Female; D006801:Humans; D008565:Membrane Proteins / Q000737:chemistry / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D018394:CA-125 Antigen; D000939:Epitopes; C451759:MUC16 protein, human; D008565:Membrane Proteins
keywords: CA125; biomarker; epitope mapping; glycopeptides; ovarian cancer