title: Expression of LacZ from the htrA, nirB and groE promoters in a Salmonella vaccine strain: influence of growth in mammalian cells.
abstract: Attenuated Salmonella strains are currently being evaluated as live vectors for the delivery of heterologous antigens to the mammalian mucosal and systemic immune systems. An approach to improving the stability of heterologous antigen expression during vaccination is to drive expression of the foreign protein from promoters, e.g. nirB, that become activated when Salmonella enter the host. Salmonella strains were constructed that harboured similar multicopy plasmids encoding the lacZ gene. In each strain, lacZ expression was driven from either the nirB, htrA or groE promoters. Expression of LacZ increased in all vaccine strains as they were shifted from conditions of low to high temperature. In addition, expression of lacZ driven from the htrA and nirB promoters significantly increased when the Salmonella entered eukaryotic cells, including macrophages. Expression of lacZ from the groE promoter was significantly elevated in macrophages but not in cells derived from epithelia. These promoters may be useful for optimising heterologous antigen expression within immune cells of the host.
authors.affiliation: Department of Biochemistry, Imperial College of Science, Technology and Medicine, London, UK.
authors.forename: P
authors.initials: P
authors.lastname: Everest
authors.forename: G
authors.initials: G
authors.lastname: Frankel
authors.forename: J
authors.initials: J
authors.lastname: Li
authors.forename: P
authors.initials: P
authors.lastname: Lund
authors.forename: S
authors.initials: S
authors.lastname: Chatfield
authors.forename: G
authors.initials: G
authors.lastname: Dougan
mesh_terms: D000941:Antigens / Q000096:biosynthesis / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D001428:Bacterial Vaccines / Q000235:genetics*; D002478:Cells, Cultured; D018833:Chaperonins; D004337:Drug Carriers; D029968:Escherichia coli Proteins; D015964:Gene Expression Regulation, Bacterial; D006360:Heat-Shock Proteins / Q000235:genetics; D006358:Hot Temperature; D008264:Macrophages / Q000382:microbiology; D009572:Nitrite Reductases; D033903:Periplasmic Proteins; D011401:Promoter Regions, Genetic / Q000235:genetics; D012475:Salmonella / Q000235:genetics*; D012697:Serine Endopeptidases / Q000235:genetics; D014613:Vaccines, Attenuated / Q000235:genetics*; D014614:Vaccines, Synthetic / Q000235:genetics*; D001616:beta-Galactosidase / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D000941:Antigens; D001426:Bacterial Proteins; D001428:Bacterial Vaccines; D004337:Drug Carriers; D029968:Escherichia coli Proteins; C028715:GroE protein, E coli; D006360:Heat-Shock Proteins; D033903:Periplasmic Proteins; D014613:Vaccines, Attenuated; D014614:Vaccines, Synthetic; D009572:Nitrite Reductases; C079730:NirB protein, E coli; D001616:beta-Galactosidase; C061682:DegP protease; D012697:Serine Endopeptidases; D018833:Chaperonins