Klebsiella pneumoniae (K. pneumoniae) is a gram-negative pathogen, and Klebsiella pneumonia is one of the most common nosocomial infections. Canonical NLRP3 and NLRC4 inflammasome was found involved in innate immune response against K. pneumoniae, but the role of caspase-11 in K. pneumoniae infection remains undefined. It was shown that Caspase-11 knockout blocked K. pneumoniae-induced IL-1α and IL-1β secretion and pyroptosis of bone marrow-derived macrophages (BMDMs). Furthermore, caspase-11-/- mice exhibited impaired neutrophil recruitment and bacterial clearance in the early stage of K. pneumoniae infection, accompanied by a reduction in IL-1α production. Moreover, IL-1α neutralizing antibody pretreatment was found to inhibit neutrophil recruitment and bacterial clearance of wild-type mice. Together, these data suggest that caspase-11/IL-1α pathway plays an important role in defending against K. pneumoniae by recruiting neutrophils in the early stage of infection.

中文翻译：

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Caspase-11缺乏症会损害肺炎克雷伯菌肺炎早期的中性粒细胞募集和细菌清除。

肺炎克雷伯菌（K. pneumoniae）是革兰氏阴性病原体，肺炎克雷伯菌是最常见的医院感染之一。发现规范的NLRP3和NLRC4炎性小体参与了针对肺炎克雷伯菌的先天免疫应答，但caspase-11在肺炎克雷伯菌感染中的作用仍然不确定。结果表明，Caspase-11基因敲除可阻断肺炎克雷伯菌诱导的骨髓来源巨噬细胞（BMDMs）分泌的IL-1α和IL-1β并引起细胞凋亡。此外，在肺炎克雷伯菌感染的早期，caspase-11-/-小鼠表现出中性粒细胞募集受损和细菌清除受损，并伴有IL-1α产生减少。此外，发现IL-1α中和抗体预处理可抑制中性粒细胞募集和野生型小鼠的细菌清除。一起，