title: Characterization of porcine dendritic cell response to Streptococcus suis.
abstract: Streptococcus suis is a major swine pathogen and important zoonotic agent causing mainly septicemia and meningitis. However, the mechanisms involved in host innate and adaptive immune responses toward S. suis as well as the mechanisms used by S. suis to subvert these responses are unknown. Here, and for the first time, the ability of S. suis to interact with bone marrow-derived swine dendritic cells (DCs) was evaluated. In addition, the role of S. suis capsular polysaccharide in modulation of DC functions was also assessed. Well encapsulated S. suis was relatively resistant to phagocytosis, but it increased the relative expression of Toll-like receptors 2 and 6 and triggered the release of several cytokines by DCs, including IL-1β, IL-6, IL-8, IL-12p40 and TNF-α. The capsular polysaccharide was shown to interfere with DC phagocytosis; however, once internalized, S. suis was readily destroyed by DCs independently of the presence of the capsular polysaccharide. Cell wall components were mainly responsible for DC activation, since the capsular polysaccharide-negative mutant induced higher cytokine levels than the wild-type strain. The capsular polysaccharide also interfered with the expression of the co-stimulatory molecules CD80/86 and MHC-II on DCs. To conclude, our results show for the first time that S. suis interacts with swine origin DCs and suggest that these cells might play a role in the development of host innate and adaptive immunity during an infection with S. suis serotype 2.
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, J2S 2M2, Canada. marcelo.gottschalk@umontreal.ca.
authors.forename: Marie-Pier
authors.initials: MP
authors.lastname: Lecours
authors.forename: Mariela
authors.initials: M
authors.lastname: Segura
authors.forename: Claude
authors.initials: C
authors.lastname: Lachance
authors.forename: Tufaria
authors.initials: T
authors.lastname: Mussa
authors.forename: Charles
authors.initials: C
authors.lastname: Surprenant
authors.forename: Maria
authors.initials: M
authors.lastname: Montoya
authors.forename: Marcelo
authors.initials: M
authors.lastname: Gottschalk
mesh_terms: D000818:Animals; D016667:Bacterial Capsules / Q000378:metabolism*; D001853:Bone Marrow; D002470:Cell Survival; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology* / Q000382:microbiology / Q000502:physiology; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005434:Flow Cytometry / Q000662:veterinary; D018613:Microscopy, Confocal / Q000662:veterinary; D046529:Microscopy, Electron, Transmission / Q000662:veterinary; D010587:Phagocytosis; D016133:Polymerase Chain Reaction / Q000662:veterinary; D013290:Streptococcal Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary*; D017011:Streptococcus suis / Q000502:physiology*; D013552:Swine; D013553:Swine Diseases / Q000276:immunology* / Q000382:microbiology; D051193:Toll-Like Receptors / Q000235:genetics / Q000378:metabolism
chemical_list: D016207:Cytokines; D051193:Toll-Like Receptors; C028096:capsular polysaccharide, Streptococcus suis type 2