小鼠巨噬细胞对钩端螺旋体56606v和56606a的吞噬及炎症应答的比较研究

Comparison of the phagocytosis and inflammatory response of murine macrophages infected by Leptospira strains 56606v and 56606a

目的·比较问号钩端螺旋体56606v株和56606a株对小鼠巨噬细胞的感染情况,探究致病性钩端螺旋体的致病机制。方法·用问号钩端螺旋体强毒株56606v株和减毒株56606a株分别感染C57BL/6小鼠腹腔巨噬细胞后,对样本进行免疫荧光染色,观察巨噬细胞对钩端螺旋体的吞噬及清除能力,并通过realtime-PCR检测感染后巨噬细胞的细胞因子的表达。结果·免疫荧光染色和realtime-PCR结果均发现在感染72 h后,56606v株仍能在巨噬细胞中存活,而56606a株不能在巨噬细胞中存活;巨噬细胞对56606v株的吞噬率高于对56606a株的吞噬率,而感染56606v株后细胞因子的表达低于感染56606a株后的水平。结论·问号钩端螺旋体强毒株56606v株能在巨噬细胞中存活,并引起较低的炎症反应,可借此逃避免疫细胞的杀伤从而引发疾病;而减毒株56606a株被巨噬细胞吞噬后则被清除,且引发较强的炎症反应,易被机体免疫细胞清除,从而不引起疾病。

Objective·To compare the response and consequence of mouse macrophages infected by Leptospira interrogans 56606v and 56606a,and explore the mechanisms of pathogenic Leptospira to cause disease.Methods·Peritoneal macrophages of C57BL/6 mice were infected by pathogenic Leptospira 56606v and non-pathogenic Leptospira 56606a respectively.Immunofluorescence staining was performed to observe phagocytosis and clearance of Leptospira after infection,and realtime-PCR was used to determine cytokine production of macrophages.Results·After 72-hour infection,strain 56606v exhibited a lower phagocytic rate but survived after incubation with peritoneal macrophages compared with strain 56606a,which showed a higher phagocytic rate but was cleared at that time point.Additionally,cytokine production of macrophages incubated with 56606v was lower than that with 56606a.Conclusion·Leptospira interrogans strain 56606v can survive in macrophages,which may contribute to evasion from phagocytic clearance and lead to disease,while strain 56606a can be cleared,which implicates a lower pathogenicity.