title: Critical role for Streptococcus suis cell wall modifications and suilysin in resistance to complement-dependent killing by dendritic cells.
abstract: Streptococcus suis is an emerging zoonotic agent of septicemia and meningitis. Knowledge on host immune responses toward S. suis and strategies used by this pathogen for subversion of these responses is scarce. Here, S. suis modulation of dendritic cell (DC) functions were assessed for the first time. Using S. suis knockout mutants in capsular polysaccharide (CPS) expression, it was shown that CPS blocks DC phagocytosis and impairs cytokine release by hindering cell wall components. Mutants impaired in D-alanylation of lipoteichoic acid (LTA) or N-deacetylation of peptidoglycan (PG) further demonstrated the importance of cell wall in modulation of DC activation. Notably, LTA/PG modifications were identified as major players in resistance to complement-dependent killing by DCs. Finally, S. suis hemolysin was partially involved in cytokine release and also contributed to bacterial escape of opsonophagocytosis. Overall, S. suis uses its arsenal of virulence factors to modulate DC functions and escape immune surveillance.
authors.affiliation: Groupe de Recherche sur les Maladies Infectieuses du Porc and Centre de Recherche en Infectiologie Porcine, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, Québec, Canada. mariela.segura@umontreal.ca
authors.forename: Marie-Pier
authors.initials: MP
authors.lastname: Lecours
authors.forename: Marcelo
authors.initials: M
authors.lastname: Gottschalk
authors.forename: Mathieu
authors.initials: M
authors.lastname: Houde
authors.forename: Paul
authors.initials: P
authors.lastname: Lemire
authors.forename: Nahuel
authors.initials: N
authors.lastname: Fittipaldi
authors.forename: Mariela
authors.initials: M
authors.lastname: Segura
mesh_terms: D000818:Animals; D016667:Bacterial Capsules / Q000378:metabolism*; D001433:Bacteriolysis; D002473:Cell Wall / Q000276:immunology / Q000378:metabolism*; D003165:Complement System Proteins / Q000276:immunology*; D016207:Cytokines / Q000378:metabolism; D003713:Dendritic Cells / Q000187:drug effects / Q000276:immunology*; D005260:Female; D006460:Hemolysin Proteins / Q000276:immunology* / Q000378:metabolism; D057131:Immune Evasion; D008070:Lipopolysaccharides / Q000276:immunology / Q000378:metabolism; D051379:Mice; D010457:Peptidoglycan / Q000276:immunology / Q000378:metabolism; D010587:Phagocytosis; D017011:Streptococcus suis / Q000737:chemistry / Q000276:immunology*; D013682:Teichoic Acids / Q000276:immunology / Q000378:metabolism
chemical_list: D016207:Cytokines; D006460:Hemolysin Proteins; D008070:Lipopolysaccharides; D010457:Peptidoglycan; D013682:Teichoic Acids; C104760:suilysin; C009900:lipoteichoic acid; D003165:Complement System Proteins