Salmonella Typhimurium lacking phoBR as a live vaccine candidate against poultry infection

Jung, Bogyo; Park, Soyeon; Kim, Eunsuk; Yoon, Hyunjin; Hahn, Tae-Wook

doi:10.1016/j.vetmic.2022.109342

Cited by 11 publications

(5 citation statements)

References 34 publications

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“…For the intracellular survival assay, as previously described [ 25 , 28 , 29 ], RAW264.7 cells were seeded at a density of 10 5 cells per well in 2–12 well plates. C50336, Δ cheV and Δ cheV + cheV infected the cells with an MOI of 100 and were incubated in a 37 °C, 5% CO 2 incubator for 2 h. The cells were then washed twice with PBS to remove non-adherent/invasive bacteria.…”

Section: Methodsmentioning

confidence: 99%

CheV enhances the virulence of Salmonella Enteritidis, and the Chev-deleted Salmonella vaccine provides immunity in mice

Zhang,

Wu,

Wang

et al. 2024

BMC Vet Res

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Background Salmonella enteritidis (SE) is a major zoonotic pathogen and causes infections in a variety of hosts. The development of novel vaccines for SE is necessary to eradicate this pathogen. Genetically engineered attenuated live vaccines are more immunogenic and safer. Thus, to develop a live attenuated Salmonella vaccine, we constructed a cheV gene deletion strain of SE (named ΔcheV) and investigated the role of cheV in the virulence of SE. First, the ability to resist environmental stress in vitro, biofilm formation capacity, drug resistance and motility of ΔcheV were analyzed. Secondly, the bacterial adhesion, invasion, intracellular survival assays were performed by cell model. Using a mouse infection model, an in vivo virulence assessment was conducted. To further evaluate the mechanisms implicated by the reduced virulence, qPCR analysis was utilized to examine the expression of the strain’s major virulence genes. Finally, the immune protection rate of ΔcheV was evaluated using a mouse model. Results Compared to C50336, the ΔcheV had significantly reduced survival ability under acidic, alkaline and thermal stress conditions, but there was no significant difference in survival under oxidative stress conditions. There was also no significant change in biofilm formation ability, drug resistance and motility. It was found that the adhesion ability of ΔcheV to Caco-2 cells remained unchanged, but the invasion ability and survival rate in RAW264.7 cells were significantly reduced. The challenge assay results showed that the LD50 values of C50336 and ΔcheV were 6.3 × 105 CFU and 1.25 × 107 CFU, respectively. After the deletion of the cheV gene, the expression levels of fimD, flgG, csgA, csgD, hflK, lrp, sipA, sipB, pipB, invH, mgtC, sodC, rfbH, xthA and mrr1 genes were significantly reduced. The live attenuated ΔcheV provided 100% protection in mice against SE infection. Conclusion All the results confirmed that the deletion of the cheV gene reduces the virulence of SE and provides significant immune protection in mice, indicating that ΔcheV could be potential candidates to be explored as live-attenuated vaccines.

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Section: Methodsmentioning

confidence: 99%

CheV enhances the virulence of Salmonella Enteritidis, and the Chev-deleted Salmonella vaccine provides immunity in mice

Zhang,

Wu,

Wang

et al. 2024

BMC Vet Res

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“…Referring to previous methods ( Jung et al, 2022 ), RAW264.7 was seeded into two 12-well plates at a density of 3 × 10 5 cells/well and incubated for 12 h. After washing with PBS, the cells were infected with bacterial cultures of C50336, Δ pal , and Δ pal + pal at an MOI of 100:1, followed by centrifugation at 1000 rpm for 10 min. After a 2-h incubation, the cells were washed with PBS to remove unadhered bacteria.…”

Section: Methodsmentioning

confidence: 99%

The peptidoglycan-associated lipoprotein gene mutant elicits robust immunological defense in mice against Salmonella enteritidis

Zhao,

Duan,

Zhang

et al. 2024

Front. Microbiol.

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BackgroundSalmonella enteritidis (S. enteritidis), a zoonotic pathogen with a broad host range, presents a substantial threat to global public health safety. Vaccination stands as an effective strategy for the prevention and control of S. enteritidis infection, highlighting an immediate clinical need for the creation of safe and efficient attenuated live vaccines.MethodsIn this study, a S. enteritidis peptidoglycan-associated lipoprotein (pal) gene deletion strain (Δpal), was constructed. To assess its virulence, we conducted experiments on biofilm formation capability, motility, as well as cell and mouse infection. Subsequently, we evaluated the immune-protective effect of Δpal.ResultsIt was discovered that deletion of the pal gene reduced the biofilm formation capability and motility of S. enteritidis. Cell infection experiments revealed that the Δpal strain exhibited significantly decreased abilities in invasion, adhesion, and intracellular survival, with downregulation of virulence gene expression, including mgtC, invH, spvB, sipA, sipB, ssaV, csgA, and pipB. Mouse infection experiments showed that the LD50 of Δpal increased by 104 times, and its colonization ability in mouse tissue organs was significantly reduced. The results indicated that the pal gene severely affected the virulence of S. enteritidis. Further, immunogenicity evaluation of Δpal showed a significant enhancement in the lymphocyte transformation proliferation capability of immunized mice, producing high titers of specific IgG and IgA, suggesting that Δpal possesses good immunogenicity. Challenge protection tests demonstrated that the strain could provide 100% immune protection against wild-type strains in mice.DiscussionThis study proves that the pal gene influences the virulence of S. enteritidis, and Δpal could serve as a candidate strain for attenuated live vaccines, laying the foundation for the development of attenuated live vaccines against Salmonella.

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“…Therefore, vaccination has become an effective means to prevent Salmonella typhimurium infection [17]. With an increasing number of studies on the pathogenic mechanism of Salmonella typhimurium, constructing attenuated strains by deleting virulence genes is also increasingly applied to the development of attenuated vaccines [18,19,20,21] The SptP protein, one of the vital virulence proteins of Salmonella typhimurium [22,23], induces rearrangement of the actin skeleton of the cell after Salmonella entry and facilitates bacterial invasion [24,25]. SptP plays an essential regulatory role in the intracellular survival of Salmonella typhimurium.…”

Section: Introductionmentioning

confidence: 99%

Construction of Salmonella typhimurium sptP mutant and evaluation of its characterization and immunoprotective effect

Zhou,

Ding,

et al. 2024

Preprint

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Salmonella typhimurium is a pathogen that poses a severe health risk to humans and animals. We discussed the feasibility of the Salmonella typhimurium ΔsptP mutant as a live attenuated vaccine, constructed a Salmonella typhimurium ΔsptP mutant by homologous recombination, and evaluated its biological functions, such as growth characteristics, immunogenicity, and protective properties. We found that the ΔsptP gene mutant of Salmonella typhimurium is a safe and effective live attenuated vaccine. The mutation of the sptP gene does not affect the growth and character of bacteria and has genetic stability. Compared with wild-type Salmonella typhimurium, the colonization ability of the mutant in RAW264.7 mouse macrophages and mice was significantly weakened. The median lethal dose (LD50) of the ΔsptP mutant was 39.92 times that of the wild-type strain, indicating that the virulence of the ΔsptP mutant was significantly weakened. After inoculation with 2×104 CFU ΔsptP mutant and one booster immunization, the mice were able to resist 87.5% of the virulent strains compared to the PBS control group, and the level of IgG antibodies produced by the mutant was similar to that of the wild-type strain. These results show that ΔsptP mutants of Salmonella typhimurium are significantly less virulent to mice than wild-type strains. The sptP mutant is immunogenic and protective in mice, and ΔsptP can be used as a live attenuated vaccine for Salmonella typhimurium disease.

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Salmonella Typhimurium lacking phoBR as a live vaccine candidate against poultry infection

Cited by 11 publications

References 34 publications

CheV enhances the virulence of Salmonella Enteritidis, and the Chev-deleted Salmonella vaccine provides immunity in mice

CheV enhances the virulence of Salmonella Enteritidis, and the Chev-deleted Salmonella vaccine provides immunity in mice

The peptidoglycan-associated lipoprotein gene mutant elicits robust immunological defense in mice against Salmonella enteritidis

Construction of Salmonella typhimurium sptP mutant and evaluation of its characterization and immunoprotective effect

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