Galectin‐3 binds Neisseria meningitidis and increases interaction with phagocytic cells |
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Authors: | Paola Quattroni Yanwen Li Davide Lucchesi Sebastian Lucas Derek W Hood Martin Herrmann Hans‐Joachim Gabius Christoph M Tang Rachel M Exley |
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Institution: | 1. Centre for Molecular Microbiology and Infection, Department of Microbiology, Imperial College London, , London, SW7 2AZ UK;2. Department of Histopathology, KCL School of Medicine, St. Thomas's Hospital, , London, SE1?7EH UK;3. Department of Paediatrics, Weatherall Institute of Molecular Medicine, John Radcliffe Hospital, University of Oxford, , Oxford, OX3?9DS UK;4. Department of Internal Medicine 3, Friedrich‐Alexander University of Erlangen‐Nuremberg, , 91054 Erlangen, Germany;5. Chair of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig‐Maximilians‐University Munich, , 80539 Munich, Germany;6. Sir William Dunn School of Pathology, , Oxford, OX1?3RE UK |
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Abstract: | Galectin‐3 is expressed and secreted by immune cells and has been implicated in multiple aspects of the inflammatory response. It is a glycan binding protein which can exert its functions within cells or exogenously by binding cell surface ligands, acting as a molecular bridge or activating signalling pathways. In addition, this lectin has been shown to bind to microorganisms. In this study we investigated the interaction between galectin‐3 and Neisseria meningitidis, an important extracellular human pathogen, which is a leading cause of septicaemia and meningitis. Immunohistochemical analysis indicated that galectin‐3 is expressed during meningococcal disease and colocalizes with bacterial colonies in infected tissues from patients. We show that galectin‐3 binds to N. meningitidis and we demonstrate that this interaction requiresfull‐length, intact lipopolysaccharide molecules. We found that neither exogenous nor endogenous galectin‐3 contributes to phagocytosis of N. meningitidis; instead exogenous galectin‐3 increases adhesion to monocytes and macrophages but not epithelial cells. Finally we used galectin‐3 deficient (Gal‐3?/?) mice to evaluate the contribution of galectin‐3 to meningococcal bacteraemia. We found that Gal‐3?/? mice had significantly lower levels of bacteraemia compared with wild‐type mice after challenge with live bacteria, indicating that galectin‐3 confers an advantage to N. meningitidis during systemic infection. |
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