Proinflammatory cytokine and chemokine modulation by Streptococcus suis in a whole-blood culture system.
Streptococcus suis is an important swine and human pathogen. Inflammation, a hallmark of S. suis infection, is thought to be responsible for most clinical signs of meningitis, septicaemia and sudden death. In this work, using a porcine whole blood model, S. suis serotype 2 was shown to trigger the release of several pro-inflammatory cytokines as evaluated by reverse transcriptase-PCR and enzyme-linked immunosorbent assay. Although individual variations were observed among different S. suis strains, no correlations were observed between the strain origin/phenotype and cytokine levels. Live bacteria induced higher tumour necrosis factor alpha, interleukin-1 beta (IL-1beta) and IL-6 levels than did heat-killed bacteria. In contrast, heat-killed bacteria stimulated higher levels of IL-8 and monocyte chemotactic protein one (MCP-1). The bacterial cell wall was observed to be the major cytokine-inducting components, whereas capsule expression was important for MCP-1 activation. The presence of specific antibodies suppressed bacterial growth resulting in significantly reduced levels of cytokine production. Thus, antibody-mediated bacterial phagocytosis combined with suppressed inflammation may be beneficial for infection control strategies. We provide first evidence of S.suis-induction of pro-inflammatory swine cytokines and demonstrate the strength and relevance of the whole blood culture systems in the investigation of S. suis modulation of cytokine production.
Segura
Mariela
M
Canadian Research Network on Bacterial Pathogens of Swine, Faculté de Médecine Vétérinaire, Université de Montréal, St-Hyacinthe, QC, Canada.
Vanier
Ghyslaine
G
Al-Numani
Dina
D
Lacouture
Sonia
S
Olivier
Martin
M
Gottschalk
Marcelo
M
D000818:Animals; D001769:Blood / Q000276:immunology / Q000382:microbiology; D018925:Chemokines / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D015870:Gene Expression; D007249:Inflammation / Q000097:blood / Q000276:immunology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013290:Streptococcal Infections / Q000097:blood / Q000276:immunology*; D017011:Streptococcus suis / Q000276:immunology*; D013552:Swine
D018925:Chemokines; D016207:Cytokines; D012333:RNA, Messenger