1. Minimal epitope for Mannitou IgM on paucimannose-carrying glycoproteins
- Author
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Ana Gimeno, Jesús Jiménez-Barbero, Stefania Robakiewicz, Sandra Delgado, Clarisse Bridot, Begoña Echeverria, Ann Dansercoer, Nicola G. A. Abrescia, Jérôme de Ruyck, Sonia Serna, Shubham Semwal, Mikel Azkargorta, Ruud H. P. Wilbers, Ana Ardá, Savvas N. Savvides, Diego Charro, Niels C. Reichardt, Kenneth Verstraete, Julie Bouckaert, Kim van Noort, Unité de Glycobiologie Structurale et Fonctionnelle UMR 8576 (UGSF), Institut National de la Recherche Agronomique (INRA)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Unité de Glycobiologie Structurale et Fonctionnelle (UGSF), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Centro de Investigación Cooperativa en Biomateriales (CIC biomaGUNE), Cell Biology and Stem Cells Unit (CICbioGUNE), Technologic Park of Bizkaia, VIB-UGent Center for Inflammation Research [Gand, Belgique] (IRC), VIB [Belgium], Wageningen University and Research [Wageningen] (WUR), Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN), Instituto de Salud Carlos III [Madrid] (ISC)-ministerio de ciencia e innovacion, Université de Lille-Centre National de la Recherche Scientifique (CNRS), Unité de Glycobiologie Structurale et Fonctionnelle - UMR 8576 (UGSF), Université de Lille, CNRS, Unité de Glycobiologie Structurale et Fonctionnelle (UGSF) - UMR 8576, Centro de Investigación Cooperativa en Biomateriales [CIC biomaGUNE], Cell Biology and Stem Cells Unit [CICbioGUNE], VIB-UGent Center for Inflammation Research [Gand, Belgique] [IRC], Wageningen University and Research [Wageningen] [WUR], Unité de Glycobiologie Structurale et Fonctionnelle UMR 8576 [UGSF], and Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine [CIBER-BBN]
- Subjects
[SDV]Life Sciences [q-bio] ,Mannose ,Biochemistry ,Epitope ,Epitopes ,Mice ,chemistry.chemical_compound ,0302 clinical medicine ,Mannitou ,N-linked glycosylation ,BINDING ,Medicine and Health Sciences ,AFFINITY ,Mammals ,chemistry.chemical_classification ,0303 health sciences ,biology ,PROLIFERATION ,paucimannosidic epitopes ,Schistosoma mansoni ,N-GLYCOSYLATION ,CANCER ,3. Good health ,DNA-Binding Proteins ,GLYCAN MICROARRAYS ,030220 oncology & carcinogenesis ,N-glycan ,Antibody ,Glycan ,core fucose ,IgM ,CORE FUCOSYLATION ,03 medical and health sciences ,Antigen ,Polysaccharides ,Animals ,Humans ,Laboratorium voor Nematologie ,Fucose ,Glycoproteins ,030304 developmental biology ,Membrane Proteins ,Biology and Life Sciences ,IgM binding ,Immunoglobulin M ,chemistry ,ANTIBODIES ,biology.protein ,Laboratory of Nematology ,Glycoprotein ,ELASTASE - Abstract
Paucimannosidic glycans are restricted to the core structure [Man1–3GlcNAc2Fuc0–1] of N-glycans and are rarely found in mammalian tissues. Yet, especially [Man2-3GlcNAc2Fuc1] have been found significantly upregulated in tumors, including in colorectal and liver cancer. Mannitou IgM is a murine monoclonal antibody that was previously shown to recognize Man3GlcNAc2 with an almost exclusive selectivity. Here, we have sought the definition of the minimal glycan epitope of Mannitou IgM, initiated by screening on a newly designed paucimannosidic glycan microarray; among the best binders were Man3GlcNAc2 and its α1,6 core-fucosylated variant, Man3GlcNAc2Fuc1. Unexpectedly and in contrast to earlier findings, Man5GlcNAc2-type structures bind equally well and a large tolerance was observed for substitutions on the α1,6 arm. It was confirmed that any substitution on the single α1,3-linked mannose completely abolishes binding. Surface plasmon resonance for kinetic measurements of Mannitou IgM binding, either directly on the glycans or as presented on omega-1 and kappa-5 soluble egg antigens from the helminth parasite Schistosoma mansoni, showed submicromolar affinities. To characterize the epitope in greater and atomic detail, saturation transfer difference nuclear magnetic resonance spectroscopy was performed with the Mannitou antigen-binding fragment. The STD-NMR data demonstrated the strongest interactions with the aliphatic protons H1 and H2 of the α1–3-linked mannose and weaker imprints on its H3, H4 and H5 protons. In conclusion, Mannitou IgM binding requires a nonsubstituted α1,3-linked mannose branch of paucimannose also on proteins, making it a highly specific tool for the distinction of concurrent human tumor-associated carbohydrate antigens.
- Published
- 2021
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