Gulig P A, Curtiss R
Department of Biology, Washington University, St. Louis, Missouri 63130.
Infect Immun. 1987 Dec;55(12):2891-901. doi: 10.1128/iai.55.12.2891-2901.1987.
We investigated the role of the 100-kilobase (kb) plasmid of Salmonella typhimurium in the virulence of this organism for mice. Three strains, LT2-Z, SR-11, and SL1344, which possessed 100-kb plasmids with identical restriction enzyme digestion profiles, were cured of their respective 100-kb plasmids after Tnmini-tet was used to label plasmids. Curing wild-type virulent strains SR-11 and SL1344 raised peroral 50% lethal doses from 3 x 10(5) and 6 x 10(4) CFU, respectively, to greater than 10(8) CFU. Both wild-type strains had intraperitoneal 50% lethal doses of less than 50 CFU, whereas the intraperitoneal 50% lethal doses for cured SR-11 and SL1344 were less than 50 and 400 CFU, respectively. Reintroduction of the Tnmini-tet-labeled, 100-kb plasmid restored wild-type virulence. Invasion from Peyer's patches to mesenteric lymph nodes and spleens after peroral inoculation was the stage of pathogenesis most affected by curing S. typhimurium of the 100-kb plasmid. Wild-type S. typhimurium replicated in spleens of mice inoculated intravenously to a greater extent than did plasmid-cured derivatives. Wild-type and cured strains equally adhered to and invaded Henle-407, HEp-2, and CHO cells; furthermore, the presence of the 100-kb plasmid was not necessary for replication of S. typhimurium within CHO cells. The 100-kb plasmid had no effect on phagocytosis and killing of S. typhimurium by murine peritoneal macrophages in vitro and in vivo. Similarly, wild-type and plasmid-cured strains were resistant to killing by 90% normal human, rabbit, and guinea pig sera. All wild-type and plasmid-cured S. typhimurium strains possessed complete lipopolysaccharide, as determined by silver staining solubilized cells in sodium dodecyl sulfate-polyacrylamide gels. We have confirmed the role of the 100-kb plasmid of S. typhimurium in virulence, primarily in invasion to mesenteric lymph nodes and spleens after peroral inoculation of mice. Involvement of the 100-kb plasmid in infection of mesenteric lymph nodes and spleens suggests a role for the plasmid in the complex interaction of S. typhimurium with cells of the reticuloendothelial system.
我们研究了鼠伤寒沙门氏菌100千碱基（kb）质粒在该菌对小鼠的毒力中的作用。三株菌株LT2-Z、SR-11和SL1344，它们拥有具有相同限制性内切酶消化图谱的100-kb质粒，在用Tnmini-tet标记质粒后，各自的100-kb质粒被消除。消除野生型毒力菌株SR-11和SL1344后，经口半数致死剂量分别从3×10⁵和6×10⁴CFU提高到大于10⁸CFU。两种野生型菌株的腹腔半数致死剂量均小于50 CFU，而消除质粒后的SR-11和SL1344的腹腔半数致死剂量分别小于50和400 CFU。重新导入Tnmini-tet标记的100-kb质粒可恢复野生型毒力。经口接种后从派伊尔结侵入肠系膜淋巴结和脾脏是鼠伤寒沙门氏菌消除100-kb质粒后发病机制中受影响最大的阶段。野生型鼠伤寒沙门氏菌在静脉接种小鼠的脾脏中比消除质粒的衍生物复制程度更高。野生型和消除质粒的菌株对Henle-407、HEp-2和CHO细胞的黏附和侵入能力相同；此外，100-kb质粒的存在对于鼠伤寒沙门氏菌在CHO细胞内的复制并非必需。100-kb质粒在体外和体内对鼠腹膜巨噬细胞吞噬和杀灭鼠伤寒沙门氏菌均无影响。同样，野生型和消除质粒的菌株对90%正常人、兔和豚鼠血清的杀灭具有抗性。通过十二烷基硫酸钠-聚丙烯酰胺凝胶中银染溶解细胞测定，所有野生型和消除质粒的鼠伤寒沙门氏菌菌株均具有完整的脂多糖。我们已证实鼠伤寒沙门氏菌100-kb质粒在毒力中的作用，主要是在经口接种小鼠后侵入肠系膜淋巴结和脾脏。100-kb质粒参与肠系膜淋巴结和脾脏的感染表明该质粒在鼠伤寒沙门氏菌与网状内皮系统细胞的复杂相互作用中发挥作用。
