Down-regulation of key virulence factors makes the Salmonella enterica serovar typhimurium rfaH mutant a promising live-attenuated vaccine candidate

Gabor Nagy, Vittoria Danino, Ulrich Dobrindt, Mark Pallen, Roy Chaudhuri, L. Emődy, Jay C. Hinton, Jörg Hacker

Research output: Contribution to journalArticle

76 Citations (Scopus)

Abstract

Mutants of Salmonella enterica serovar Typhimurium that lack the transcriptional regulator RfaH are efficient as live oral vaccines against salmonellosis in mice. We show that the attenuation of the vaccine candidate strain is associated with reduced net growth in epithelial and macrophage cells. In order to identify the relevant RfaH-dependent genes, the RfaH regulon was determined with S. enterica serovars Enteritidis and Typhimurium using whole-genome Salmonella microarrays. As well as impacting the expression of genes involved in lipopolysaccharide (LPS) core and O-antigen synthesis, the loss of RfaH results in a marked down-regulation of SPI-4 genes, the flagellum/chemotaxis system, and type III secretion system 1. However, a proportion of these effects could have been the indirect consequence of the altered expression of genes required for LPS biosynthesis. Direct and indirect effects of the rfaH mutation were dissociated by genome-wide transcriptional profiling of a structural deep-rough LPS mutant (waaG). We show that truncation of LPS itself is responsible for the decreased intracellular yield observed for γrfaH strains. LPS mutants do not differ in replication ability; rather, they show increased susceptibility to antimicrobial peptides in the intracellular milieu. On the other hand, evidence that deletion of rfaH, as well as some other genes involved in LPS biosynthesis, results in enhanced invasion of various mammalian cells is shown. Exposure of common minor antigens in the absence of serovar-specific antigens might be responsible for the observed cross-reactive nature of the elicited immune response upon vaccination. Increased invasiveness of the Salmonella rfaH mutant into antigen-presenting cells, combined with increased intracellular killing and the potential for raising a cross-protective immune response, renders the rfaH mutant an ideal vaccine candidate.

Original languageEnglish
Pages (from-to)5914-5925
Number of pages12
JournalInfection and Immunity
Volume74
Issue number10
DOIs
Publication statusPublished - Oct 2006

Fingerprint

Attenuated Vaccines
Salmonella enterica
Virulence Factors
Lipopolysaccharides
Down-Regulation
Salmonella
Vaccines
Salmonella Vaccines
Genome
Genes
Gene Expression
Antigens
Regulon
O Antigens
Salmonella enteritidis
Aptitude
Flagella
Antigen-Presenting Cells
Chemotaxis
Serogroup

ASJC Scopus subject areas

  • Immunology

Cite this

Down-regulation of key virulence factors makes the Salmonella enterica serovar typhimurium rfaH mutant a promising live-attenuated vaccine candidate. / Nagy, Gabor; Danino, Vittoria; Dobrindt, Ulrich; Pallen, Mark; Chaudhuri, Roy; Emődy, L.; Hinton, Jay C.; Hacker, Jörg.

In: Infection and Immunity, Vol. 74, No. 10, 10.2006, p. 5914-5925.

Research output: Contribution to journalArticle

Nagy, Gabor ; Danino, Vittoria ; Dobrindt, Ulrich ; Pallen, Mark ; Chaudhuri, Roy ; Emődy, L. ; Hinton, Jay C. ; Hacker, Jörg. / Down-regulation of key virulence factors makes the Salmonella enterica serovar typhimurium rfaH mutant a promising live-attenuated vaccine candidate. In: Infection and Immunity. 2006 ; Vol. 74, No. 10. pp. 5914-5925.
@article{b9495f8992c545f0b2c1d0821d491b5a,
title = "Down-regulation of key virulence factors makes the Salmonella enterica serovar typhimurium rfaH mutant a promising live-attenuated vaccine candidate",
abstract = "Mutants of Salmonella enterica serovar Typhimurium that lack the transcriptional regulator RfaH are efficient as live oral vaccines against salmonellosis in mice. We show that the attenuation of the vaccine candidate strain is associated with reduced net growth in epithelial and macrophage cells. In order to identify the relevant RfaH-dependent genes, the RfaH regulon was determined with S. enterica serovars Enteritidis and Typhimurium using whole-genome Salmonella microarrays. As well as impacting the expression of genes involved in lipopolysaccharide (LPS) core and O-antigen synthesis, the loss of RfaH results in a marked down-regulation of SPI-4 genes, the flagellum/chemotaxis system, and type III secretion system 1. However, a proportion of these effects could have been the indirect consequence of the altered expression of genes required for LPS biosynthesis. Direct and indirect effects of the rfaH mutation were dissociated by genome-wide transcriptional profiling of a structural deep-rough LPS mutant (waaG). We show that truncation of LPS itself is responsible for the decreased intracellular yield observed for γrfaH strains. LPS mutants do not differ in replication ability; rather, they show increased susceptibility to antimicrobial peptides in the intracellular milieu. On the other hand, evidence that deletion of rfaH, as well as some other genes involved in LPS biosynthesis, results in enhanced invasion of various mammalian cells is shown. Exposure of common minor antigens in the absence of serovar-specific antigens might be responsible for the observed cross-reactive nature of the elicited immune response upon vaccination. Increased invasiveness of the Salmonella rfaH mutant into antigen-presenting cells, combined with increased intracellular killing and the potential for raising a cross-protective immune response, renders the rfaH mutant an ideal vaccine candidate.",
author = "Gabor Nagy and Vittoria Danino and Ulrich Dobrindt and Mark Pallen and Roy Chaudhuri and L. Emődy and Hinton, {Jay C.} and J{\"o}rg Hacker",
year = "2006",
month = "10",
doi = "10.1128/IAI.00619-06",
language = "English",
volume = "74",
pages = "5914--5925",
journal = "Infection and Immunity",
issn = "0019-9567",
publisher = "American Society for Microbiology",
number = "10",

}

TY - JOUR

T1 - Down-regulation of key virulence factors makes the Salmonella enterica serovar typhimurium rfaH mutant a promising live-attenuated vaccine candidate

AU - Nagy, Gabor

AU - Danino, Vittoria

AU - Dobrindt, Ulrich

AU - Pallen, Mark

AU - Chaudhuri, Roy

AU - Emődy, L.

AU - Hinton, Jay C.

AU - Hacker, Jörg

PY - 2006/10

Y1 - 2006/10

N2 - Mutants of Salmonella enterica serovar Typhimurium that lack the transcriptional regulator RfaH are efficient as live oral vaccines against salmonellosis in mice. We show that the attenuation of the vaccine candidate strain is associated with reduced net growth in epithelial and macrophage cells. In order to identify the relevant RfaH-dependent genes, the RfaH regulon was determined with S. enterica serovars Enteritidis and Typhimurium using whole-genome Salmonella microarrays. As well as impacting the expression of genes involved in lipopolysaccharide (LPS) core and O-antigen synthesis, the loss of RfaH results in a marked down-regulation of SPI-4 genes, the flagellum/chemotaxis system, and type III secretion system 1. However, a proportion of these effects could have been the indirect consequence of the altered expression of genes required for LPS biosynthesis. Direct and indirect effects of the rfaH mutation were dissociated by genome-wide transcriptional profiling of a structural deep-rough LPS mutant (waaG). We show that truncation of LPS itself is responsible for the decreased intracellular yield observed for γrfaH strains. LPS mutants do not differ in replication ability; rather, they show increased susceptibility to antimicrobial peptides in the intracellular milieu. On the other hand, evidence that deletion of rfaH, as well as some other genes involved in LPS biosynthesis, results in enhanced invasion of various mammalian cells is shown. Exposure of common minor antigens in the absence of serovar-specific antigens might be responsible for the observed cross-reactive nature of the elicited immune response upon vaccination. Increased invasiveness of the Salmonella rfaH mutant into antigen-presenting cells, combined with increased intracellular killing and the potential for raising a cross-protective immune response, renders the rfaH mutant an ideal vaccine candidate.

AB - Mutants of Salmonella enterica serovar Typhimurium that lack the transcriptional regulator RfaH are efficient as live oral vaccines against salmonellosis in mice. We show that the attenuation of the vaccine candidate strain is associated with reduced net growth in epithelial and macrophage cells. In order to identify the relevant RfaH-dependent genes, the RfaH regulon was determined with S. enterica serovars Enteritidis and Typhimurium using whole-genome Salmonella microarrays. As well as impacting the expression of genes involved in lipopolysaccharide (LPS) core and O-antigen synthesis, the loss of RfaH results in a marked down-regulation of SPI-4 genes, the flagellum/chemotaxis system, and type III secretion system 1. However, a proportion of these effects could have been the indirect consequence of the altered expression of genes required for LPS biosynthesis. Direct and indirect effects of the rfaH mutation were dissociated by genome-wide transcriptional profiling of a structural deep-rough LPS mutant (waaG). We show that truncation of LPS itself is responsible for the decreased intracellular yield observed for γrfaH strains. LPS mutants do not differ in replication ability; rather, they show increased susceptibility to antimicrobial peptides in the intracellular milieu. On the other hand, evidence that deletion of rfaH, as well as some other genes involved in LPS biosynthesis, results in enhanced invasion of various mammalian cells is shown. Exposure of common minor antigens in the absence of serovar-specific antigens might be responsible for the observed cross-reactive nature of the elicited immune response upon vaccination. Increased invasiveness of the Salmonella rfaH mutant into antigen-presenting cells, combined with increased intracellular killing and the potential for raising a cross-protective immune response, renders the rfaH mutant an ideal vaccine candidate.

UR - http://www.scopus.com/inward/record.url?scp=33749258050&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33749258050&partnerID=8YFLogxK

U2 - 10.1128/IAI.00619-06

DO - 10.1128/IAI.00619-06

M3 - Article

C2 - 16988271

AN - SCOPUS:33749258050

VL - 74

SP - 5914

EP - 5925

JO - Infection and Immunity

JF - Infection and Immunity

SN - 0019-9567

IS - 10

ER -