Hirakata Yoichi, Kirikae Teruo, Kirikae Fumiko, Yamaguchi Toshiyuki, Izumikawa Kohichi, Takemura Hiromu, Maesaki Shigefumi, Tomono Kazunori, Yamada Yasuaki, Kamihira Shimeru, Nakano Masayasu, Kitamura Satoshi, Kohno Shigeru
Departments of Laboratory Medicine, Jichi Medical School, Minamikawachi, Tochigi 329-0498, Japan.
Departments of Pulmonary Medicine, Jichi Medical School, Minamikawachi, Tochigi 329-0498, Japan.
J Med Microbiol. 1999 May;48(5):471-477. doi: 10.1099/00222615-48-5-471.
The ability of several Pseudomonas aeruginosa exo-enzymes, including exotoxin A (ETA), to induce inflammation and their influence on endotoxin-induced tumour necrosis factor (TNF) production in murine lung were evaluated. Intratracheal administration of lipopolysaccharide (LPS; 0.1-10 microg/mouse), 2(-1) LD50 of P. aeruginosa alkaline protease (7.5 microg/mouse) and elastase (1.2 microg/mouse) elevated total cell number and the percentage of neutrophils in broncho-alveolar lavage fluid (BALF), whereas ETA (0.1 microg/mouse) did not. LPS induced TNF production in BALF in a dose-dependent manner, whereas the P. aeruginosa exo-enzymes did not. When ETA was inoculated into the respiratory tract before LPS, production of TNF in BALF was significantly suppressed in a dose-dependent manner. ETA also suppressed TNF production by alveolar macrophages (AMs) stimulated with LPS in vitro. Flow cytometric analysis showed that ETA markedly reduced the expression of CD14 and CD11c/CD18 on the surface of AMs. ETA also depressed partially the expression of TNF-alpha mRNA in AMs. These findings suggest that ETA regulates TNF production in murine lung by suppressing LPS receptor expression, mRNA expression and protein synthesis and/or secretion of TNF.
评估了几种铜绿假单胞菌外酶（包括外毒素A（ETA））诱导炎症的能力及其对小鼠肺中内毒素诱导的肿瘤坏死因子（TNF）产生的影响。气管内给予脂多糖（LPS；0.1 - 10微克/小鼠）、2（-1）LD50的铜绿假单胞菌碱性蛋白酶（7.5微克/小鼠）和弹性蛋白酶（1.2微克/小鼠）可提高支气管肺泡灌洗液（BALF）中的总细胞数和中性粒细胞百分比，而ETA（0.1微克/小鼠）则无此作用。LPS以剂量依赖方式诱导BALF中TNF的产生，而铜绿假单胞菌外酶则无此作用。当在LPS之前将ETA接种到呼吸道时，BALF中TNF的产生以剂量依赖方式被显著抑制。ETA还在体外抑制LPS刺激的肺泡巨噬细胞（AMs）产生TNF。流式细胞术分析表明，ETA显著降低AMs表面CD14和CD11c/CD18的表达。ETA还部分抑制AMs中TNF-α mRNA的表达。这些发现表明，ETA通过抑制LPS受体表达、TNF的mRNA表达以及蛋白质合成和/或分泌来调节小鼠肺中TNF的产生。
