Abstract: To explore the key role of neutrophils in the host response after hypervirulent K. pneumoniae sgh10 inhalation infection. Method In vivo elimination model of neutrophils was established by depleting lung tissue neutrophils in mice using monoclonal antibody anti-ly6g ( 10 mg / kg ) , and the model was evaluated by flow cytometry detection and immunofluorescence. Animals were divided into two groups, one injected with mAb and one injected with isotype control Ab at pre-infection, 24 and 48 h post infection to examine mouse survival, lung bacterial load, lung histopathology, cytokines as well as the effect of neutrophil depletion on other immune cells. Reslut The elimination effect of neutrophils was confirmed by flow cytometry and immunofluorescence assays. Depletion of neutrophils in vivo resulted in increased mortality, higher bacterial loads in the lungs, more severe lung injury and higher levels of pro-inflammatory cytokines in mice compared to controls. Furthermore, although neutrophil depleted mice are more susceptible to hypervirulent K. pneumoniae respiratory infection and cause up to 90% mortality, alterations in neutrophils did not significantly affect the levels of several other innate immune cells. Conclusion neutrophils played an important role in the host response of hypervirulent K. pneumoniae infection.

Key words: hypervirulent K. pneumoniae;neutrophils, inhalation infection, pneumonia

摘要： 目的 探究中性粒细胞在高毒力肺炎克雷伯菌 sgh10 吸入感染后宿主防御中的关键作用。 方法 使用单克隆抗体 anti-Ly6g 消除小鼠体内肺组织中性粒细胞,建立中性粒细胞体内消除模型,通过流式细胞术检测和免疫荧光对消除效果进行评价。 将动物分为两组,一组注射单克隆抗体,一组注射同型对照抗体,分别在感染前、感染后24 和 48 h,检测小鼠生存率、肺细菌载量、肺组织病理、细胞因子以及中性粒细胞消除对其他免疫细胞的影响。结果 流式细胞术和免疫荧光检测证实中性粒细胞在体内被消除。 与对照组相比,中性粒细胞消除组小鼠死亡率增加、肺部细菌载量增加、肺部病理损伤加重、促炎细胞因子水平上升。 此外,尽管中性粒细胞消除的小鼠对高毒力肺炎克雷伯菌呼吸道感染更敏感,并导致更高的死亡率,但中性粒细胞的改变并未对其他几种固有免疫细胞的水平造成显著影响。 结论 中性粒细胞在高毒力肺炎克雷伯菌 sgh10 吸入感染后宿主应答中发挥了重要作用。

关键词: 高毒力肺炎克雷伯菌, 中性粒细胞, 吸入感染, 肺炎