Egawa K, Klein T W, Yamamoto Y, Newton C A, Friedman H
Department of Medical Microbiology and Immunology, University of South Florida College of Medicine, Tampa 33612.
Proc Soc Exp Biol Med. 1992 Jul;200(3):338-42. doi: 10.3181/00379727-200-43439.
Macrophages from A/J mice are permissive for growth of Legionella pneumophila, an intracellular opportunistic pathogen that grows preferentially in macrophages. Macrophages from other mouse strains are highly resistant to growth of Legionella. In the present study, it was found that macrophages from A/J mice are readily activated by pretreatment with lipopolysaccharide (LPS), so that the cells do not permit Legionella to replicate in vitro, as occurs when untreated macrophages from A/J mice are cultured with these organisms for 48 hr. The augmentation of Legionella growth inhibition by LPS-activated macrophages from nonpermissive BDF1 mice also occurred. After in vitro infection, there was a 1000-fold increase in the number of Legionella in A/J macrophages and approximately a 10-fold increase in BDF1 macrophages, but LPS treatment of macrophages from either strain resulted in marked growth restrictions. This suppression was both dose dependent as well as dependent upon the time of addition of the LPS to the macrophages. Furthermore, the lipid A component of LPS was found to be as effective as the intact LPS in activating macrophages to inhibit the intracellular growth of Legionella. Further studies concerning the mechanisms involved are clearly warranted and in progress.
A/J小鼠的巨噬细胞允许嗜肺军团菌生长，嗜肺军团菌是一种细胞内机会性病原体，优先在巨噬细胞中生长。其他小鼠品系的巨噬细胞对嗜肺军团菌的生长具有高度抗性。在本研究中，发现A/J小鼠的巨噬细胞经脂多糖（LPS）预处理后很容易被激活，因此这些细胞不允许嗜肺军团菌在体外复制，这与未处理的A/J小鼠巨噬细胞与这些病原体培养48小时时的情况不同。来自非允许性BDF1小鼠的LPS激活巨噬细胞对嗜肺军团菌生长的抑制作用也增强。体外感染后，A/J巨噬细胞中嗜肺军团菌的数量增加了1000倍，BDF1巨噬细胞中增加了约10倍，但对任一品系的巨噬细胞进行LPS处理都会导致明显的生长限制。这种抑制作用既依赖于剂量，也依赖于将LPS添加到巨噬细胞中的时间。此外，发现LPS的脂质A成分在激活巨噬细胞以抑制嗜肺军团菌的细胞内生长方面与完整的LPS一样有效。显然有必要对相关机制进行进一步研究，目前正在进行中。
