CHARACTERIZATION OF LISTERIA-MONOCYTOGENES PATHOGENESIS IN A STRAIN EXPRESSING PERFRINGOLYSIN-O IN-PLACE OF LISTERIOLYSIN-O
CHARACTERIZATION OF LISTERIA-MONOCYTOGENES PATHOGENESIS IN A STRAIN EXPRESSING PERFRINGOLYSIN-O IN-PLACE OF LISTERIOLYSIN-O
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DOI：
10.1128/iai.62.12.5608-5613.1994
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发表时间：
1994-12-01
影响因子：
3.1
通讯作者：
PORTNOY, DA
中科院分区：
文献类型：
--
作者：
JONES, S;PORTNOY, DA
李斯特菌溶血素O(Listeriolysin O，LLO)是一种能使单核细胞增生性李斯特氏菌从宿主细胞液泡中逃逸的致孔溶血素。从编码LLO的HLY启动子下游克隆了细胞溶血素-产气相溶血素O(PFA)的结构基因，该基因位于质粒和单核细胞增多性乳杆菌染色体上。这两个菌株都能分泌活性的PFO，尽管其调节机制与LLO不同。染色体上表达PFO的菌株具有细胞内生长和细胞间扩散的特征。通过细菌F-肌动蛋白的免疫荧光染色确定，与野生型相比，它从宿主细胞空泡中逃脱的效率为%。F-肌动蛋白是进入细胞质的标志。此外，它在细胞内复制，倍增时间与野生型相似，5h后，由于对宿主细胞的细胞毒作用和细胞外庆大霉素的内流，生长中止。染色体上的pfo株能够在小鼠L(2)成纤维细胞中形成空斑，但与野生型相比，其效率为20%，并且空斑明显较小。两株表达PFO的菌株对小鼠都是完全无毒的。这些结果表明，PFO可以介导从宿主细胞空泡中逃逸，但不能补充HLY缺失菌株的毒力。
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 (pfa) 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 L(2) 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.