铜绿假单胞菌生物被膜对巨噬细胞的免疫逃逸作用及机制

目的 探讨铜绿假单胞菌生物被膜对巨噬细胞的免疫逃逸作用以及相关机制。方法 用PMA刺激THP-1细胞获得巨噬细胞模型。用6孔板建膜法获得铜绿假单胞菌生物被膜菌。分别用铜绿假单胞菌的生物被膜菌和浮游菌感染巨噬细胞，观察巨噬细胞形态的变化，并检测巨噬细胞的细胞毒性和吞噬功能的变化。进一步用ELISA试剂盒检测感染的巨噬细胞培养上清中炎症细胞因子IL-1β的变化。结果 成功构建巨噬细胞模型和铜绿假单胞菌生物被膜菌模型。与感染了浮游菌的细胞相比，感染了生物被膜菌的巨噬细胞形态变化小，释放的LDH降低，吞噬功能减弱，IL-1β的表达量减少。结论 铜绿假单胞菌生物被膜菌可以逃逸巨噬细胞的免疫防御作用，其机制可能与降低巨噬细胞的炎症反应有关。

Biofilm-derived Pseudomonas aeruginosa immune escape frommacrophages and its mechanisms

Objective To explore the interaction between biofilm-derived Pseudomonas aeruginosa and macrophages and the possible mechanisms of Pseudomonas aeruginosa biofilm immune evasion. Methods The macrophages were derived from THP-1 cells using PMA. The Pseudomonas aeruginosa biofilm was generated in a 6-well polystyrene plates. Macrophages were infected with the biofilm and planktonic cells derived from Pseudomonas aeruginosa respectively. The morphological changes of infected macrophages were observed; the cytotoxicity of the macrophages were analyzed by detecting the activity of lactate dehydrogenase (LDH), and the phagocytic function was assessed using the method described in literatures. ELISA method was used to detect the secretion of proinflammatory cytokine IL-1β. Results Compared with the cells infected with planktonic Pseudomonas aeruginosa, the macrophages infected with biofilm Pseudomonas aeruginosa showed less morphological changes and produced less LDH; its phagocytic function was weakened, and the secretion of IL-1β reduced. Conclusion Biofilm-forming Pseudomonas aeruginosa can evade the host defence. The possible mechanism may be related with the reduced inflammatory response of host by its biofilm.