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首页> 外文期刊>Infection and immunity >Characterization of Listeria monocytogenes pathogenesis in a strain expressing perfringolysin O in place of listeriolysin O.
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Characterization of Listeria monocytogenes pathogenesis in a strain expressing perfringolysin O in place of listeriolysin O.

机译：在表达穿孔素溶菌素O代替李斯特菌溶血素O的菌株中表征单核细胞增生李斯特菌的发病机理。

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Listeriolysin O (LLO) is a pore-forming cytolysin that enables Listeria monocytogenes to escape from a host cell vacuole. The structural gene for the related cytolysin perfringolysin O (pfo) was cloned downstream from the promoter for hly, the gene encoding LLO, both on a plasmid and on the L. monocytogenes chromosome. Both strains secreted active PFO, although regulation was not identical to that of LLO. The chromosomal PFO-expressing strain was characterized for intracellular growth and cell-to-cell spread. It escaped from a host cell vacuole with 64% efficiency compared with the wild type as determined by immunofluorescent staining of bacteria for F-actin, a marker for entry into the cytoplasm. In addition, it replicated intracellularly with a doubling time similar to that of the wild type for 5 h, after which growth was aborted because of a cytotoxic effect on the host cell and influx of extracellular gentamicin. The chromosomal PFO strain was able to plaque in mouse L2 fibroblasts, but it did so at 20% efficiency compared with the wild type and the plaques were significantly smaller. Both strains expressing PFO were completely avirulent in mice. These results indicate that PFO can mediate escape from a host cell vacuole but cannot complement an hly deletion strain for virulence.
机译：李斯特菌溶血素O（LLO）是一种成孔的细胞溶素，可使单核细胞增生李斯特菌从宿主细胞液泡中逸出。相关的细胞溶素溶血性纤溶酶溶蛋白O（pfo）的结构基因被克隆到hly启动子的下游，该基因在质粒和单核细胞增生李斯特氏菌染色体上均编码LLO。两种菌株均分泌活性PFO，尽管其调控与LLO不同。染色体PFO表达菌株的特征是细胞内生长和细胞间扩散。通过对细菌进行F-肌动蛋白（一种进入细胞质的标志物）进行免疫荧光染色确定，与野生型相比，它以64％的效率从宿主细胞液泡中逸出。此外，它以与野生型相似的倍增时间在细胞内复制了5小时，此后由于对宿主细胞的细胞毒性作用和细胞外庆大霉素的流入而中止了生长。染色体PFO菌株能够在小鼠L2成纤维细胞中形成噬菌斑，但与野生型相比，效率为20％，并且噬菌斑明显较小。两种表达PFO的菌株在小鼠中都完全无毒。这些结果表明，PFO可以介导宿主细胞液泡的逃逸，但是不能补充hly缺失菌株的毒力。

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