Clerc P L, Ryter A, Mounier J, Sansonetti P J
Infect Immun. 1987 Mar;55(3):521-7. doi: 10.1128/iai.55.3.521-527.1987.
In Shigella flexneri a 220-kilobase plasmid encodes the ability to invade nonprofessional phagocytes by a mechanism similar to phagocytosis. In this report, the continuous macrophage cell line J774 was used to study the intracellular fate of both invasive and noninvasive strains. pWR100, the virulence plasmid of S. flexneri serotype 5, mediated very efficient and rapid killing of J774 macrophages, as measured by cellular detachment and uptake of trypan blue. For this to occur, the bacteria had to be within the cells, since the macrophages were protected by cytochalasin D. A battery of strains differing in their levels of Shiga toxin production showed that inhibition of protein synthesis by Shiga toxin, as measured by [35S]methionine incorporation into infected macrophages, was not required for early killing of cells. Damage to J774 macrophages rather correlated with the ability of invasive bacteria to rapidly and efficiently lyse the membrane of the phagocytic vacuole. The role of the release of bacteria within the cytosol for subsequent expression of cytotoxic activity is discussed, and mitochondria are proposed as a potential target for this activity.
在福氏志贺菌中，一个220千碱基的质粒编码了通过类似于吞噬作用的机制侵入非专职吞噬细胞的能力。在本报告中，连续巨噬细胞系J774被用于研究侵袭性和非侵袭性菌株的细胞内命运。福氏志贺菌5型的毒力质粒pWR100介导了对J774巨噬细胞非常高效且快速的杀伤，这通过细胞脱离和台盼蓝摄取来衡量。要发生这种情况，细菌必须在细胞内，因为巨噬细胞受到细胞松弛素D的保护。一系列志贺毒素产生水平不同的菌株表明，通过[35S]甲硫氨酸掺入感染的巨噬细胞来衡量，志贺毒素对蛋白质合成的抑制对于细胞的早期杀伤并非必需。对J774巨噬细胞的损伤反而与侵袭性细菌快速有效地裂解吞噬泡膜的能力相关。讨论了胞质溶胶中细菌释放对随后细胞毒性活性表达的作用，并提出线粒体是这种活性的潜在靶点。
