Open AccessExpression of LacZ from the htrA, nirB and groE promoters in a Salmonella vaccine strain: Influence of growth in mammalian cells
Author(s) -
Everest Paul,
Frankel Gad,
Li Jingli,
Lund Peter,
Chatfield Steven,
Dougan Gordon
Publication year - 1995
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1995.tb07398.x
Subject(s) - heterologous , biology , promoter , salmonella , plasmid , microbiology and biotechnology , lac operon , immune system , heterologous expression , gene expression , antigen , gene , recombinant dna , bacteria , genetics
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.