Expression of heterologous antigens in Salmonella Typhimurium vaccine vectors using the in vivo-inducible, SPI-2 promoter, ssaG.
DNA derived from regions upstream of the Salmonella enterica serovar Typhimurium ssaG gene were used to drive expression of different reporter genes in putative Salmonella vaccine strains. Expression from ssaG was shown to be significantly upregulated once Salmonella had entered murine or human macrophages, and levels of expression were dependent on the length of the ssaG 5' sequence incorporated. S. Typhimurium derivatives harbouring the Escherichia coli heat labile toxin B subunit (LT-B) fused to various lengths of the ssaG promoter region were also constructed as single copy chromosomal integrations. Expression of LT-B by these Salmonella derivatives was detected at significant levels after intra-macrophage survival and mice immunised with these derivatives mounted marked anti-LT-B humoral antibody responses.
McKelvie
Nicola D
ND
Microscience Limited, 540-545 Eskdale Road, Winnersh Triangle, Wokingham, Berkshire RG41 5TU, UK. n.mckelvie@microscience.com
Stratford
Richard
R
Wu
Tao
T
Bellaby
Trevor
T
Aldred
Emma
E
Hughes
Nicky J
NJ
Chatfield
Steven N
SN
Pickard
Derek
D
Hale
Christine
C
Dougan
Gordon
G
Khan
Shahid A
SA
D000818:Animals; D000942:Antigens, Bacterial / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D002470:Cell Survival; D002478:Cells, Cultured; D002876:Chromosomes, Bacterial / Q000235:genetics / Q000276:immunology; D003470:Culture Media; D017931:DNA Primers; D005434:Flow Cytometry; D005798:Genes, Bacterial / Q000235:genetics / Q000276:immunology*; D017930:Genes, Reporter / Q000235:genetics; D006801:Humans; D007074:Immunoglobulin G / Q000096:biosynthesis; D007763:Lac Operon / Q000235:genetics; D008264:Macrophages / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D010957:Plasmids / Q000235:genetics / Q000276:immunology; D011401:Promoter Regions, Genetic / Q000235:genetics / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D022562:Salmonella Vaccines / Q000235:genetics / Q000276:immunology*; D012486:Salmonella typhimurium / Q000235:genetics / Q000276:immunology*; D019444:Vaccines, DNA / Q000096:biosynthesis / Q000276:immunology
D000942:Antigens, Bacterial; D003470:Culture Media; D017931:DNA Primers; D007074:Immunoglobulin G; D022562:Salmonella Vaccines; D019444:Vaccines, DNA