A comprehensive study of the contribution of Salmonella enterica serovar Typhimurium SPI2 effectors to bacterial colonization, survival and replication in typhoid fever, macrophage and epithelial cell infection models
A comprehensive study of the contribution of Salmonella enterica serovar Typhimurium SPI2 effectors to bacterial colonization, survival and replication in typhoid fever, macrophage and epithelial cell infection models
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DOI：
10.4161/viru.2.3.15894
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发表时间：
2011-05-01
期刊：
影响因子：
5.2
通讯作者：
Finlay, B. Brett
中科院分区：
文献类型：
--
作者：
Buckner, Michelle M. C.;Croxen, Matthew A.;Finlay, B. Brett
肠道沙门氏菌血清型是革兰氏阴性菌病原体，可引发包括肠胃炎和伤寒在内的人类疾病。摄入后，沙门氏菌穿过肠道上皮屏障，在此它们被巨噬细胞和树突状细胞吞噬，这使得它们在伤寒病例中能够扩散到全身各处。沙门氏菌利用由沙门氏菌致病岛（SPI）1和2编码的两种三型分泌系统将毒力蛋白注入宿主细胞以改变细胞功能。SPI1参与宿主细胞入侵和炎症反应，而SPI2是吞噬细胞内的生存、复制以及全身扩散所必需的。在这项研究中，在小鼠伤寒的体内模型以及巨噬细胞和上皮细胞感染的细胞培养模型中，对几乎所有已知的SPI2效应蛋白的作用进行了检测。在肠道沙门氏菌血清型鼠伤寒沙门氏菌中构建了SPI2效应蛋白无标记的框内缺失突变体，并检测了16种不同突变体的定植和复制能力。在伤寒模型中，我们发现ΔspvB和ΔspiC突变体在肠道和全身部位的定植能力减弱，而ΔsseF突变体在全身器官中的定植能力减弱。在上皮细胞中，所有突变体的复制程度与野生型相同。在巨噬细胞中，与野生型沙门氏菌相比，ΔspiC、ΔsteC、ΔspvB、ΔssseK1/K2/K3、ΔsifA和ΔsifB菌株的复制能力较差。这项研究对在各种感染模型中相同条件下评估的大多数已知SPI2效应蛋白进行了全面筛选，为这些效应蛋白的作用及相互作用的比较研究提供了基础。
Salmonella enterica serovars are Gram-negative bacterial pathogens responsible for human diseases including gastroenteritis and typhoid fever. After ingestion, Salmonella cross the intestinal epithelial barrier, where they are phagocytosed by macrophages and dendritic cells, which then enables their spread to systemic sites during cases of typhoid fever. Salmonella use two type 3 secretion systems encoded by Salmonella pathogenicity islands (SPI) 1 and 2 to inject virulence proteins into host cells to modify cellular functions. SPI1 is involved in host cell invasion and inflammation, whereas SPI2 is required for intracellular survival and replication within phagocytes, and systemic spread. In this study the contribution of nearly all known SPI2 effectors was examined in an in vivo model of murine typhoid fever and cell culture models of macrophage and epithelial cell infection. Unmarked, in-frame deletions of SPI2 effectors were engineered in S. enterica serovar Typhimurium and the ability of the 16 different mutants to colonize and replicate was examined. In the typhoid model, we found that Delta spvB and Delta spiC mutants were attenuated for colonization of intestinal and systemic sites, while the Delta sseF mutant was attenuated in systemic organs. In epithelial cells, all mutants replicated to the same extent as the wild-type. In macrophages, Delta spiC, Delta steC, Delta spvB, Delta ssseK1/K2/K3, Delta sifA and Delta sifB strains replicated poorly in comparison to wild-type Salmonella. This study provides a thorough screen of the majority of the known SPI2 effectors evaluated under the same conditions in various models of infection, providing a foundation for comparative examination of the roles and interactions of these effectors.