Chabot-Roy Geneviève, Willson Philip, Segura Mariela, Lacouture Sonia, Gottschalk Marcelo
Groupe de recherche sur les maladies infectieuses du porc (GREMIP), Faculté de médecine vétérinaire, Université de Montréal, 3200 Sicotte, St-Hyacinthe, Qué., Canada J2S 2M2.
Microb Pathog. 2006 Jul;41(1):21-32. doi: 10.1016/j.micpath.2006.04.001. Epub 2006 May 22.
Streptococcus suis serotype 2 is an important swine pathogen responsible for diverse infections, mainly meningitis. Virulence factors and the pathogenesis of infection are not well understood. Neutrophils may play an important role in the pathogenesis of infection given that infiltration by neutrophils and mononuclear cells are frequently observed in lesions caused by S. suis. The objective of this work was to study the interactions between S. suis serotype 2 and porcine neutrophils. Results showed that suilysin is toxic to neutrophils and this could help S. suis evade innate immunity. Moreover, suilysin appears to affect complement-dependent killing by decreasing the opsonization of S. suis and the bactericidal capacity of neutrophils. Our results confirm that capsule polysaccharide protects S. suis against killing and phagocytosis by neutrophils. We also showed that the presence of specific IgG against S. suis serotype 2 promoted killing by neutrophils, indicating that the induction of a strong humoral response is beneficial for clearance of this pathogen.
猪链球菌2型是一种重要的猪病原体，可引发多种感染，主要是脑膜炎。其毒力因子和感染发病机制尚未完全明确。鉴于在猪链球菌引起的病变中经常观察到中性粒细胞和单核细胞浸润，中性粒细胞可能在感染发病机制中起重要作用。本研究的目的是探讨猪链球菌2型与猪中性粒细胞之间的相互作用。结果表明，溶菌酶对中性粒细胞有毒性，这可能有助于猪链球菌逃避先天免疫。此外，溶菌酶似乎通过降低猪链球菌的调理作用和中性粒细胞的杀菌能力来影响补体依赖性杀伤。我们的结果证实，荚膜多糖可保护猪链球菌免受中性粒细胞的杀伤和吞噬。我们还表明，针对猪链球菌2型的特异性IgG的存在促进了中性粒细胞的杀伤作用，这表明诱导强烈的体液反应有利于清除该病原体。
