Salmonella protease mutants, clpP and especially htrA, are candidate live oral vaccines in humans. A functional and mature immune system is, however, required to cope with them in mice. Here, we test the cytokine response of highly susceptible germ-free pigs to infection with Salmonella Typhimurium clpP and htrA mutants. Cytokine levels (IL-4, IL-10, IL-18 and IFN-gamma) were measured by ELISA in plasma and washes from the terminal small bowel 24h after oral challenge. Unlike the infection with the wild type strain, no IFN-gamma response and low IL-18 intestinal levels were found in pigs infected with the protease mutants. Despite this and regardless of partially reduced ability of htrA and clpP mutants to invade and multiply in a 3D4 porcine macrophage-like cell line, both the mutants were as virulent as was the wild type LT2 strain and caused fatal septicaemia in germ-free pigs. IFN-gamma and IL-18 response therefore did not correlate with the virulence of Salmonella Typhimurium. Our results indicate that htrA and clpP attenuations should be used with caution in populations in which an increased number of immunocompromised individuals can be expected.
- MeSH
- buněčné linie MeSH
- cytokiny imunologie metabolismus MeSH
- financování organizované MeSH
- gnotobiologické modely MeSH
- makrofágy imunologie mikrobiologie MeSH
- mutace MeSH
- náchylnost k nemoci MeSH
- prasata MeSH
- proteasy genetika metabolismus MeSH
- Salmonella typhimurium enzymologie genetika imunologie patogenita MeSH
- salmonelová infekce u zvířat imunologie metabolismus mikrobiologie MeSH
- salmonelové vakcíny imunologie MeSH
- virulence MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
Using transcriptional promoter fusions, we investigated the expression of selected SPI-1 and SPI-2 genes of Salmonella enterica serovar Typhimurium (S. Typhimurium). Promoters of genes related to the invasion of the epithelial cell (hilA, hilC, hilD, invF, sicA, sopA, sopB and sopE2) were active in... ( view more ) Luria-Bertani (LB) medium and LB with butyrate but were suppressed by bile salts and in glucose minimal (M9) medium. Genes related to S. Typhimurium intracellular survival (phoP, ssrA, ssaB, ssaG, sifA, sifB and pipB) were characterized by their expression in stationary phase in LB and M9 medium. Activity of phoP and ssrA promoters indicated that these might be expressed inside the gut. SPI-1 genes were expressed on the transition to stationary phase while SPI-2 genes were expressed in stationary phase. Among SPI-1 genes, those with regulatory functions preceded in expression the effector genes and sop genes were expressed in the order of sopA, sopB and sopE2, showing hierarchy in the expression of S. Typhimurium virulence genes.
- MeSH
- exprese genu fyziologie genetika imunologie MeSH
- finanční podpora výzkumu jako téma MeSH
- financování vládou MeSH
- genetické techniky trendy využití MeSH
- luciferasy genetika MeSH
- polymerázová řetězová reakce s reverzní transkripcí využití MeSH
- promotorové oblasti (genetika) imunologie účinky léků MeSH
- reportérové geny genetika MeSH
- Salmonella typhimurium genetika imunologie metabolismus MeSH
- transkripční faktory Sp genetika MeSH
- virulence genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
Plasmids of Salmonella enterica vary in size from 2 to more than 200 kb. The best described group of plasmids are the virulence plasmids (50-100 kb in size) present in serovars Enteritidis, Typhimurium, Dublin, Cholerae-suis, Gallinarum, Pullorum and Abortus-ovis. They all encode spvRABCD genes involved in intra-macrophage survival of Salmonella. Another group of high molecular weight plasmids are plasmids responsible for antibiotic resistance. Since most of these plasmids are conjugative, besides storage of genetic information, they contribute to the spread of genes in bacterial populations. The low molecular weight plasmids are the last group of plasmids found in S. enterica. Some of them have been shown to increase resistance to phage infection due to the presence of restriction modification systems. Despite limited knowledge on their function, their presence or absence is frequently used for strain differentiation in epidemiological studies.
- MeSH
- bakteriální léková rezistence genetika MeSH
- faktory virulence genetika MeSH
- financování organizované MeSH
- molekulová hmotnost MeSH
- plazmidy genetika MeSH
- Salmonella enterica genetika patogenita účinky léků MeSH
- salmonelová infekce u zvířat mikrobiologie MeSH
- virulence genetika MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- přehledy MeSH
- Publikační typ
- abstrakt z konference MeSH
