title: Galectin-3 binds Neisseria meningitidis and increases interaction with phagocytic cells.
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.
authors: Centre for Molecular Microbiology and Infection, Department of Microbiology, Imperial College London, London, UK.
authors: Paola
authors: P
authors: Quattroni
authors: Yanwen
authors: Y
authors: Li
authors: Davide
authors: D
authors: Lucchesi
authors: Sebastian
authors: S
authors: Lucas
authors: Derek W
authors: DW
authors: Hood
authors: Martin
authors: M
authors: Herrmann
authors: Hans-Joachim
authors: HJ
authors: Gabius
authors: Christoph M
authors: CM
authors: Tang
authors: Rachel M
authors: RM
authors: Exley
mesh_terms: D000818:Animals; D016470:Bacteremia / Q000276:immunology / Q000382:microbiology; D001422:Bacterial Adhesion; D002460:Cell Line; D004195:Disease Models, Animal; D004847:Epithelial Cells / Q000276:immunology / Q000382:microbiology; D037502:Galectin 3 / Q000276:immunology / Q000378:metabolism*; D054884:Host-Pathogen Interactions; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D009345:Neisseria meningitidis / Q000276:immunology / Q000472:pathogenicity* / Q000502:physiology*; D010586:Phagocytes / Q000276:immunology / Q000382:microbiology*
chemical_list: D037502:Galectin 3