title: Lipooligosaccharide and polysaccharide capsule: virulence factors of Neisseria meningitidis that determine meningococcal interaction with human dendritic cells.
abstract: In this work we analyzed the roles of meningococcal lipooligosaccharide (LOS) and capsule expression in the interaction of Neisseria meningitidis with human dendritic cells (DC). Infection of DC with serogroup B wild-type meningococci induced a strong burst of the proinflammatory cytokines and chemokines tumor necrosis factor alpha, interleukin-6 (IL-6), and IL-8. In contrast, a serogroup B mutant strain lacking LOS expression barely led to cytokine induction, demonstrating that meningococcal LOS is the main mediator of the proinflammatory response in human DC. Sialylation of meningococcal LOS did not influence cytokine secretion by DC. However, we found the phagocytosis of N. meningitidis by human DC to be inhibited by LOS sialylation. In addition, the expression of the meningococcal serogroup A, B, and C capsules dramatically reduced DC adherence of N. meningitidis and phagocytosis to some extent. Hence, LOS sialylation and capsule expression are independent mechanisms protecting N. meningitidis from the phagocytic activity of human DC.
authors.affiliation: Institut für Hygiene und Mikrobiologie, Universität Würzburg. Universitätsklinik für Frauenheilkunde. Dermatologische Universitätsklinik, 97080 Würzburg, Germany.
authors.forename: Alexandra
authors.initials: A
authors.lastname: Unkmeir
authors.forename: Ulrike
authors.initials: U
authors.lastname: Kämmerer
authors.forename: Anne
authors.initials: A
authors.lastname: Stade
authors.forename: Claudia
authors.initials: C
authors.lastname: Hübner
authors.forename: Sabine
authors.initials: S
authors.lastname: Haller
authors.forename: Annette
authors.initials: A
authors.lastname: Kolb-Mäurer
authors.forename: Matthias
authors.initials: M
authors.lastname: Frosch
authors.forename: Guido
authors.initials: G
authors.lastname: Dietrich
mesh_terms: D016667:Bacterial Capsules / Q000633:toxicity*; D001770:Blood Bactericidal Activity; D016207:Cytokines / Q000096:biosynthesis; D003713:Dendritic Cells / Q000276:immunology* / Q000382:microbiology; D006801:Humans; D008070:Lipopolysaccharides / Q000633:toxicity*; D019158:N-Acetylneuraminic Acid / Q000378:metabolism; D009345:Neisseria meningitidis / Q000276:immunology / Q000472:pathogenicity*; D010587:Phagocytosis; D014774:Virulence
chemical_list: D016207:Cytokines; D008070:Lipopolysaccharides; C023023:lipid-linked oligosaccharides; D019158:N-Acetylneuraminic Acid