1Laboratoire UPRES EA3826, Thérapeutiques Cliniques et Expérimentales des Infections, Faculté de Médecine, Université de Nantes, Nantes, France. 2CHU Nantes, Pôle Anesthésie Réanimations, Service d'Anesthésie Réanimation Chirurgicale, Hôtel Dieu, Nantes, France.
Crit Care Med. 2014 Jun;42(6):e441-50. doi: 10.1097/CCM.0000000000000311.
Pseudomonas aeruginosa infection is a clinically relevant infection involved in pneumonia in ICUs. Understanding the type of immune response initiated by the host during pneumonia would help defining new strategies to interfere with the bacteria pathogenicity. In this setting, the role of natural killer cells remains controversial. We assessed the role of systemic natural killer cells in a Pseudomonas aeruginosa mouse pneumonia model.
Experimental study.
Research laboratory from a university hospital.
RjOrl:SWISS and BALB/cJ mice (weight, 20-24 g).
Lung injuries were assessed by bacterial load, myeloperoxidase activity, endothelial permeability (pulmonary edema), immune cell infiltrate (histological analysis), proinflammatory cytokine release, and Ly6-G immunohistochemistry. Bacterial loads were assessed in the lungs and spleen. Natural killer cell number and status were assessed in spleen (flow cytometry and quantitative polymerase chain reaction). Depletion of natural killer cells was achieved through an IV anti-asialo-GM1 antibody injection.
Pseudomonas aeruginosa tracheal instillation led to an acute pneumonia with a rapid decrease of bacterial load in lungs and with an increase of endothelial permeability, proinflammatory cytokines (tumor necrosis factor-α and interleukin-1β), and myeloperoxidase activity followed by Ly6-G positive cell infiltrate in lungs. Pseudomonas aeruginosa was detected in the spleen. Membrane markers of activation and maturation (CD69 and KLRG1 molecules) were increased in splenic natural killer cells during Pseudomonas aeruginosa infection. Splenic natural killer cells activated upon Pseudomonas aeruginosa infection produced interferon-γ but not interleukin-10. Ultimately, mice depleted of natural killer cells displayed an increased neutrophil numbers in the lungs and an increased mortality rate without bacterial load modifications in the lungs, indicating that mice depleted of natural killer cells were much more susceptible to infection compared with control animals.
We report for the first time that natural killer cells play a major role in the mice susceptibility toward a Pseudomonas aeruginosa-induced acute pneumonia model.
铜绿假单胞菌感染是一种与 ICU 肺炎相关的临床相关感染。了解宿主在肺炎过程中引发的免疫反应类型将有助于确定新的策略来干扰细菌的致病性。在这种情况下，自然杀伤细胞的作用仍存在争议。我们评估了自然杀伤细胞在铜绿假单胞菌小鼠肺炎模型中的作用。
实验研究。
大学医院的研究实验室。
RjOrl:SWISS 和 BALB/cJ 小鼠（体重 20-24 克）。
通过细菌负荷、髓过氧化物酶活性、内皮通透性（肺水肿）、免疫细胞浸润（组织学分析）、促炎细胞因子释放和 Ly6-G 免疫组织化学评估肺损伤。评估肺部和脾脏中的细菌负荷。通过静脉注射抗-asialo-GM1 抗体来评估自然杀伤细胞的数量和状态。
铜绿假单胞菌气管内滴注导致急性肺炎，肺部细菌负荷迅速下降，内皮通透性增加，促炎细胞因子（肿瘤坏死因子-α和白细胞介素-1β）和髓过氧化物酶活性增加，随后肺部 Ly6-G 阳性细胞浸润。在脾脏中检测到铜绿假单胞菌。在铜绿假单胞菌感染期间，脾自然杀伤细胞的活化和成熟（CD69 和 KLRG1 分子）的膜标记物增加。感染铜绿假单胞菌后，脾自然杀伤细胞产生干扰素-γ而不产生白细胞介素-10。最终，耗尽自然杀伤细胞的小鼠肺部中性粒细胞数量增加，死亡率增加，而肺部细菌负荷无变化，这表明与对照动物相比，耗尽自然杀伤细胞的小鼠对感染更敏感。
我们首次报道自然杀伤细胞在小鼠对铜绿假单胞菌诱导的急性肺炎模型的易感性中起主要作用。
