Lipooligosaccharide and polysaccharide capsule: virulence factors of Neisseria meningitidis that determine meningococcal interaction with human dendritic cells.
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.
Unkmeir
Alexandra
A
Institut für Hygiene und Mikrobiologie, Universität Würzburg. Universitätsklinik für Frauenheilkunde. Dermatologische Universitätsklinik, 97080 Würzburg, Germany.
Kämmerer
Ulrike
U
Stade
Anne
A
Hübner
Claudia
C
Haller
Sabine
S
Kolb-Mäurer
Annette
A
Frosch
Matthias
M
Dietrich
Guido
G
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
D016207:Cytokines; D008070:Lipopolysaccharides; C023023:lipid-linked oligosaccharides; D019158:N-Acetylneuraminic Acid