title: Development by Genetic Immunization of Monovalent Antibodies (Nanobodies) Behaving as Antagonists of the Human ChemR23 Receptor.
abstract: The generation of Abs that recognize the native conformation of G protein-coupled receptors can be a challenging task because, like most multimembrane-spanning proteins, they are extremely difficult to purify as native protein. By combining genetic immunization, phage display, and biopanning, we identified two functional monovalent Abs (nanobodies) targeting ChemR23. The two nanobodies (CA4910 and CA5183) were highly specific for the human receptor and bind ChemR23 with moderate affinity. Binding studies also showed that they share a common binding site that overlaps with that of chemerin, the natural ligand of ChemR23. Consistent with these results, we found that the nanobodies were able to antagonize chemerin-induced intracellular calcium increase. The inhibition was partial when chemerin was used as agonist and complete when the chemerin(149-157) nonapeptide was used as agonist. Engineering of a bivalent CA4910 nanobody resulted in a relatively modest increase in affinity but a marked enhancement of efficacy as an antagonist of chemerin induced intracellular calcium mobilization and a much higher potency against the chemerin(149-157) nonapeptide-induced response. We also demonstrated that the fluorescently labeled nanobodies detect ChemR23 on the surface of human primary cell populations as efficiently as a reference mouse mAb and that the bivalent CA4910 nanobody behaves as an efficient antagonist of chemerin-induced chemotaxis of human primary cells. Thus, these nanobodies constitute new tools to study the role of the chemerin/ChemR23 system in physiological and pathological conditions.
authors: Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire, Université Libre de Bruxelles, B-1070 Brussels, Belgium;
authors: Xavier
authors: X
authors: Peyrassol
authors: Structural Biology Brussels, Vrije Universiteit Brussels, B-1050 Brussels, Belgium; Structural Biology Research Center, Vlaams Instituut voor Biotechnologie, B-1050 Brussels, Belgium;
authors: Toon
authors: T
authors: Laeremans
authors: Laboratory of Molecular Immunology, Rega Institute for Medical Research, Department of Microbiology and Immunology, KU Leuven - University of Leuven, B-3000 Leuven, Belgium; and.
authors: Mieke
authors: M
authors: Gouwy
authors: Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire, Université Libre de Bruxelles, B-1070 Brussels, Belgium;
authors: Vannessa
authors: V
authors: Lahura
authors: Structural Biology Brussels, Vrije Universiteit Brussels, B-1050 Brussels, Belgium; Structural Biology Research Center, Vlaams Instituut voor Biotechnologie, B-1050 Brussels, Belgium;
authors: Maja
authors: M
authors: Debulpaep
authors: Laboratory of Molecular Immunology, Rega Institute for Medical Research, Department of Microbiology and Immunology, KU Leuven - University of Leuven, B-3000 Leuven, Belgium; and.
authors: Jo
authors: J
authors: Van Damme
authors: Structural Biology Brussels, Vrije Universiteit Brussels, B-1050 Brussels, Belgium; Structural Biology Research Center, Vlaams Instituut voor Biotechnologie, B-1050 Brussels, Belgium;
authors: Jan
authors: J
authors: Steyaert
authors: Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire, Université Libre de Bruxelles, B-1070 Brussels, Belgium; Welbio, Université Libre de Bruxelles, B-1070 Brussels, Belgium.
authors: Marc
authors: M
authors: Parmentier
authors: Institut de Recherche Interdisciplinaire en Biologie Humaine et Moléculaire, Université Libre de Bruxelles, B-1070 Brussels, Belgium; ilanger@ulb.ac.be.
authors: Ingrid
authors: I
authors: Langer
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000378:metabolism; D020013:Calcium Signaling; D002161:Camelids, New World; D061505:Cell Surface Display Techniques; D002478:Cells, Cultured; D018925:Chemokines / Q000378:metabolism; D004247:DNA / Q000008:administration & dosage; D003713:Dendritic Cells / Q000378:metabolism*; D005818:Genetic Engineering; D006801:Humans; D007114:Immunization; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism*; D051379:Mice; D010446:Peptide Fragments / Q000378:metabolism; D011485:Protein Binding; D019707:Receptors, Chemokine / Q000276:immunology*; D061905:Single-Domain Antibodies / Q000235:genetics / Q000276:immunology / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; C102741:CMKLR1 protein, human; D018925:Chemokines; D036341:Intercellular Signaling Peptides and Proteins; D010446:Peptide Fragments; C478630:RARRES2 protein, human; D019707:Receptors, Chemokine; D061905:Single-Domain Antibodies; D004247:DNA