Vectors to achieve selective expression of vaccine antigens within eukaryotic cells using Salmonella spp. as carrier strains

A set of expression vectors was constructed which allows the expression of recombinant antigens under the control of Salmonella typhi promoters that a re selectively activated after infection of eukaryotic cells. The pUC18Not derivatives contain a promoter downstream of the early transcriptional term inator from phage T7 and followed by a multiple cloning site, whereas the p Bluescript II S/K derivatives contain the ribosomal RNA T-1 transcriptional terminator and also the strong translation signals of the Escherichia coli atpE gene. The expression cassettes are flanked by NotI or PacI sites to s implify their subcloning where required. The resulting vectors were validat ed using the S1 subunit of pertussis toxin as a model antigen and Salmonell a typhimurium aroA SL7207 as a carrier. The S1 subunit was efficiently expr essed by recombinant Salmonella within Henle 407 cells. (C) 2000 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.