Sato K, Yoo Y C, Fukushima A, Saiki I, Takahashi T A, Fujihara M, Tono-Oka S, Azuma I
Institute of Immunological Science, Hokkaido University, Sapporo, Japan.
Infect Immun. 1995 Aug;63(8):2859-66. doi: 10.1128/iai.63.8.2859-2866.1995.
Bacterial endotoxin (lipopolysaccharide [LPS]) causes severe damage to the host organism as a result of excessive release of inflammatory cytokines, including interleukin-1 (IL-1) and tumor necrosis factor alpha (TNF-alpha), from mononuclear phagocytes during gram-negative bacterial infection. We evaluated the ability of a novel synthetic lipid A analog with low endotoxicity, DT-5461, to antagonize LPS-induced IL-1 and TNF-alpha production in cells of monocyte/macrophage lineage and examined the protective effect of DT-5461 against lethal endotoxic shock in mice. The IL-1- or TNF-alpha-inducing activity of DT-5461 is 100,000 to 10,000 times less active than that of Escherichia coli LPS (EcLPS) or synthetic lipid A. DT-5461 significantly inhibited EcLPS-induced IL-1 and TNF-alpha release when murine peritoneal macrophages were incubated with DT-5461 2 h prior to EcLPS stimulation at the same concentration (1 microgram/ml). The antagonistic effect of DT-5461 on the production of IL-1 and TNF-alpha induced by EcLPS occurred in a concentration-dependent manner. DT-5461 also inhibited IL-1 and TNF-alpha induction when murine peritoneal macrophages were stimulated by LPS from Salmonella typhimurium or synthetic lipid A, as well as by EcLPS, but not by muramyl dipeptides. This indicated that DT-5461 specifically antagonized the action of LPS. DT-5461 also antagonized EcLPS-mediated activation of human peripheral blood monocytes. DT-5461 blocked the binding of fluorescein isothiocyanate-labelled LPS to murine peritoneal macrophages as well as it did the binding of EcLPS and synthetic lipid A, i.e., in a concentration-dependent fashion. Injection of DT-5461 2 h before EcLPS challenge prevented the production of serum IL-1 and TNF-alpha in D-galactosamine-treated mice. Furthermore, this treatment modality protected mice against LPS-induced lethal toxicity. This study suggests that DT-5461 possesses a potent LPS antagonistic effect and may be useful in a protective strategy against lethal endotoxemia caused by gram-negative bacterial infection.
细菌内毒素（脂多糖[LPS]）在革兰氏阴性菌感染期间，由于单核吞噬细胞过度释放包括白细胞介素-1（IL-1）和肿瘤坏死因子α（TNF-α）在内的炎性细胞因子，会对宿主生物体造成严重损害。我们评估了一种新型低内毒素合成脂多糖类似物DT-5461拮抗LPS诱导单核细胞/巨噬细胞系细胞产生IL-1和TNF-α的能力，并检测了DT-5461对小鼠致死性内毒素休克的保护作用。DT-5461诱导IL-1或TNF-α的活性比大肠杆菌LPS（EcLPS）或合成脂多糖低100,000至10,000倍。当鼠腹膜巨噬细胞在与相同浓度（1微克/毫升）的EcLPS刺激前2小时与DT-5461孵育时，DT-5461显著抑制EcLPS诱导的IL-1和TNF-α释放。DT-5461对EcLPS诱导的IL-1和TNF-α产生的拮抗作用呈浓度依赖性。当鼠腹膜巨噬细胞受到鼠伤寒沙门氏菌的LPS、合成脂多糖以及EcLPS刺激时，DT-5461也抑制IL-1和TNF-α的诱导，但对胞壁酰二肽无此作用。这表明DT-5461特异性拮抗LPS的作用。DT-5461还拮抗EcLPS介导的人外周血单核细胞活化。DT-5461以浓度依赖方式阻断异硫氰酸荧光素标记的LPS与鼠腹膜巨噬细胞的结合，以及EcLPS和合成脂多糖的结合。在EcLPS攻击前2小时注射DT-5461可防止D-半乳糖胺处理的小鼠血清中IL-1和TNF-α的产生。此外，这种治疗方式可保护小鼠免受LPS诱导的致死毒性。本研究表明DT-5461具有强大的LPS拮抗作用，可能有助于制定针对革兰氏阴性菌感染所致致死性内毒素血症的保护策略。
