Changes of physiological and biochemical properties of Salmonella enterica serovar Typhimurium by deletion of cpxR and lon genes using allelic exchange method

Kim, Sam Woong; Moon, Ki Hwan; Baik, Hyung Suk; Kang, Ho Young; Kim, Sung Koo; Bahk, Jeong Dong; Hur, Jin; Lee, John Hwa

doi:10.1016/j.mimet.2009.09.025

Cited by 38 publications

(41 citation statements)

References 31 publications

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“…The lon-and cpxR-deleted ST, JOL912 delivery system can provide efficient expression of the heterologous recombinant protein without causing any safety concerns due to satisfactory attenuation of the pathogenicity (Matsui et al 2003). Given that CpxR can negatively regulate biosynthesis of the adhesin factors containing F-and P-pili and curli fimbriae (Humphreys et al 2004), and the synthesis of fimbriae and capsular polysaccharides were enhanced in the lon mutant (Kim et al 2009), the altered adhesive properties of JOL912 might influence antigen presentation in the ghost strain. This leads to the increase of sIgA titers in the immunized mice.…”

Section: Discussionmentioning

confidence: 99%

Potent immune responses induced by aSalmonellaghost delivery system that expresses the recombinant Stx2eB, FedF, and FedA proteins of theEscherichia coli-producing F18 and Shiga toxin in a murine model and evaluation of its protective effect as a porcine vaccine candidate

Won

Hwa

2017

Veterinary Quarterly

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Section: Discussionmentioning

confidence: 99%

Potent immune responses induced by aSalmonellaghost delivery system that expresses the recombinant Stx2eB, FedF, and FedA proteins of theEscherichia coli-producing F18 and Shiga toxin in a murine model and evaluation of its protective effect as a porcine vaccine candidate

Won

Hwa

2017

Veterinary Quarterly

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“…A cpxR-and lon-deleted S. Typhimurium vaccine candidate was constructed in our previous study (15). The ability of an LTB adjuvant strain to enhance immune responses and protective efficacy induced by the vaccine candidate was evaluated in the present study.…”

Section: Discussionmentioning

confidence: 99%

“…The bacterial strains and plasmids used in this study are listed in Table 1. Attenuated S. Typhimurium strain JOL911 was constructed by deletion of the cpxR and lon genes of the wild-type S. Typhimurium JOL401 isolate, as previously described (15). This strain was used as the vaccine.…”

Section: Methodsmentioning

confidence: 99%

“…We previously constructed a novel attenuated Salmonella vaccine candidate by deleting the cpxR and lon genes from a wild-type S. Typhimurium strain with an allelic exchange method (15). A balanced-lethal host-vector system based on the essential bacterial gene encoding aspartate ␤-semialdehyde dehydrogenase (asd) was used to deliver the adjuvant protein LTB from an Asd ϩ plasmid in the present study.…”

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confidence: 99%

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Enhancement of Immune Responses by an Attenuated Salmonella enterica Serovar Typhimurium Strain Secreting an Escherichia coli Heat-Labile Enterotoxin B Subunit Protein as an Adjuvant for a Live Salmonella Vaccine Candidate

Hur

Lee

2011

Clin Vaccine Immunol

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A plasmid harboring eltB, the gene encoding heat-labile enterotoxin (LTB), was constructed by insertion of eltB into an Asd ؉ ␤-lactamase signal plasmid (pMMP65). This was introduced into the ⌬lon ⌬cpxR ⌬asd Salmonella enterica serovar Typhimurium strain and designated the LTB adjuvant strain. LTB protein production and secretion from the strain were demonstrated with an immunoblot assay and enzyme-linked immunosorbent assay. The LTB strain was evaluated for enhancement of immunity and protection efficacy induced by a previously constructed live Salmonella vaccine candidate. In addition, immunization strategies using the LTB strain were optimized for effective salmonellosis protection. Seventy female BALB/c mice were divided into seven groups (A to G; n ‫؍‬ 10 mice per group). Mice were primed at 6 weeks of age and boosted at 9 weeks of age. All mice were orally challenged with a virulent wild-type strain at week 3 postbooster. Serum IgG and IgA titers from mice immunized with the LTB strain alone or with a mixture of the LTB strain and the vaccine candidate were significantly increased. The secretory IgA titers from mice immunized with the LTB strain alone or with the mixture were at least 2.2 times greater than those of control mice. In addition, all group E mice (primed with the vaccine-LTB mixture and boosted with the vaccine candidate) were free of clinical signs of salmonellosis and survived a virulent challenge. In contrast, death due to the challenge was 100% in control mice, 80% in group A mice (single immunization with the vaccine candidate), 60% in group B mice (primed and boosted with the vaccine candidate), 40% in group C mice (single immunization with the LTB strain), 30% in group D mice (primed and boosted with the LTB strain), and 30% in group F mice (primed and boosted with the vaccine-LTB mixture). These results suggest that vaccination with the LTB strain, especially when added at the prime stage only, effectively enhances immune responses and protection against salmonellosis.

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“…Table 1 contains the list of bacterial strains and plasmids used in this study. Deletion mutants were constructed by an allelic exchange method using the suicide plasmid pMEG375, as described previously (22). Wild-type S. Senftenberg (strain KVCC-BA0000590) chromosomal DNA was used as the template for amplification of the flanking sequences of the lon and cpxR genes.…”

Section: Methodsmentioning

confidence: 99%

Characterization and Evaluation of a Salmonella enterica Serotype Senftenberg Mutant Created by Deletion of Virulence-Related Genes for Use as a Live Attenuated Vaccine

Kamble

Lee

2016

Clin Vaccine Immunol

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Natural infections of chickens with Salmonella enterica subsp. enterica serovar Senftenberg (S. Senftenberg) are characterized by low-level intestinal invasiveness and insignificant production of antibodies. In this study, we investigated the potential effects of lon and cpxR gene deletions on the invasiveness of S. Senftenberg into the intestinal epithelium of chickens and its ability to induce an immune response, conferring protection against S. Senftenberg infection. With the allelic exchange method, we developed JOL1596 (⌬lon), JOL1571 (⌬cpxR), and JOL1587 (⌬lon ⌬cpxR) deletion mutants from wild-type S. Senftenberg. Deletion of the lon gene from S. Senftenberg produced increased frequency of elongated cells, with significantly greater amounts of exopolysaccharide (EPS) than in the cpxR-deleted strain and the wild-type strain. The in vivo intestinal loop invasion assay showed a significant increase in epithelial invasiveness for JOL1596 (⌬lon) and JOL1587 (⌬lon ⌬cpxR), compared to JOL1571 (⌬cpxR) and the wild-type strain. Furthermore, the S. Senftenberg wild-type and mutant strains were internalized at high levels inside activated abdominal macrophages from chicken. The in vivo inoculation of JOL1587 (⌬lon ⌬cpxR) into chickens led to colonization of the liver, spleen, and cecum for a short time. Chickens inoculated with JOL1587 (⌬lon ⌬cpxR) showed significant increases in humoral, mucosal, and cellular immune responses specific to S. Senftenberg antigens. Postchallenge, compared to the control group, the JOL1587 (⌬lon ⌬cpxR)-inoculated chickens showed not only lower persistence but also faster clearance of wild-type S. Senftenberg from the cecum. We conclude that the increased intestinal invasiveness and colonization of internal organs exhibited by JOL1587 (⌬lon ⌬cpxR) led to the establishment of immunogenicity and conferred protective efficacy against S. Senftenberg infections in chickens.S almonella enterica subsp. enterica serovar Senftenberg (S. Senftenberg) is a nontyphoidal serovar (NTS) of the Gram-negative facultative intracellular pathogen S. enterica (1). S. Senftenberg was reported as causing several foodborne outbreaks of gastroenteritis and invasive intestinal infections in humans (2-4). A previously reported nosocomial outbreak of S. Senftenberg in humans was directly related to contaminated turkey supplied to the hospital kitchen, which in turn contaminated the hospital equipment (2, 5). Various S. Senftenberg serotypes are frequently isolated from feed mills and poultry houses (6-8). The trademark of S. Senftenberg infections in chicken is heterogeneity regarding persistence in the cecum and fecal shedding (9). Also, S. Senftenberg has been shown to resist stresses such as low pH, heating, desiccation, irradiation, and cleaning and disinfection procedures used on poultry farms (1, 10, 11). To date, there have been no reported vaccine candidates for control of S. Senftenberg in poultry, and the potential risk of transmission of S. Senftenberg from chickens to human populations emphasizes the ne...

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Changes of physiological and biochemical properties of Salmonella enterica serovar Typhimurium by deletion of cpxR and lon genes using allelic exchange method

Cited by 38 publications

References 31 publications

Potent immune responses induced by aSalmonellaghost delivery system that expresses the recombinant Stx2eB, FedF, and FedA proteins of theEscherichia coli-producing F18 and Shiga toxin in a murine model and evaluation of its protective effect as a porcine vaccine candidate

Potent immune responses induced by aSalmonellaghost delivery system that expresses the recombinant Stx2eB, FedF, and FedA proteins of theEscherichia coli-producing F18 and Shiga toxin in a murine model and evaluation of its protective effect as a porcine vaccine candidate

Enhancement of Immune Responses by an Attenuated Salmonella enterica Serovar Typhimurium Strain Secreting an Escherichia coli Heat-Labile Enterotoxin B Subunit Protein as an Adjuvant for a Live Salmonella Vaccine Candidate

Characterization and Evaluation of a Salmonella enterica Serotype Senftenberg Mutant Created by Deletion of Virulence-Related Genes for Use as a Live Attenuated Vaccine

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