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In vitro Intestinal Mucosal Epithelial Responses to Wild-Type Salmonella Typhi and Attenuated Typhoid Vaccines.

Fiorentino M, Lammers KM, Levine MM, Sztein MB, Fasano A - Front Immunol (2013)

Bottom Line: Typhi exhibited alterations in the organization of tight junctions, increased paracellular permeability, and a rapid decrease in Trans-Epithelial Electrical Resistance as early as 4 h post-exposure.We conclude that wild-type S.Typhi causes marked transient alterations of the intestinal mucosa that are more pronounced than those observed with Ty21a or new generation attenuated typhoid vaccine candidates.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Mucosal Biology Research Center, University of Maryland School of Medicine Baltimore, MD, USA.

ABSTRACT
Typhoid fever, caused by S. Typhi, is responsible for approximately 200,000 deaths per year worldwide. Little information is available regarding epithelium-bacterial interactions in S. Typhi infection. We have evaluated in vitro the effects of wild-type S. Typhi, the licensed Ty21a typhoid vaccine and the leading strains CVD 908-htrA and CVD 909 vaccine candidates on intestinal barrier function and immune response. Caco2 monolayers infected with wild-type S. Typhi exhibited alterations in the organization of tight junctions, increased paracellular permeability, and a rapid decrease in Trans-Epithelial Electrical Resistance as early as 4 h post-exposure. S. Typhi triggered the secretion of interleukin (IL)-8 and IL-6. Caco2 cells infected with the attenuated strains exhibited a milder pro-inflammatory response with minimal disruption of the barrier integrity. We conclude that wild-type S. Typhi causes marked transient alterations of the intestinal mucosa that are more pronounced than those observed with Ty21a or new generation attenuated typhoid vaccine candidates.

No MeSH data available.


Related in: MedlinePlus

The effect of S. Typhi attenuated strain on the TEER of polarized Caco2 monolayers. Wild-type S. Typhi served as control. (A)Aro mutants-infected monolayers (MOI of 40:1); (B)Aro mutants-infected monolayers (MOI of 400:1). (C)Aro mutants-infected monolayers (MOI of 4000:1). (D) TEER in Caco2 cells infected with Ty21a applied apically at a MOI of 4000:1. Data are expressed as means ± SEM for triplicate samples for all conditions tested. These results are representative of three experiments with similar results. Statistical comparisons over wild-type S. Typhi at the same time point; *p < 0.05 (ANOVA).
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Figure 2: The effect of S. Typhi attenuated strain on the TEER of polarized Caco2 monolayers. Wild-type S. Typhi served as control. (A)Aro mutants-infected monolayers (MOI of 40:1); (B)Aro mutants-infected monolayers (MOI of 400:1). (C)Aro mutants-infected monolayers (MOI of 4000:1). (D) TEER in Caco2 cells infected with Ty21a applied apically at a MOI of 4000:1. Data are expressed as means ± SEM for triplicate samples for all conditions tested. These results are representative of three experiments with similar results. Statistical comparisons over wild-type S. Typhi at the same time point; *p < 0.05 (ANOVA).

Mentions: To determine the effect of attenuated mutant strains of S. Typhi on mucosal permeability in vitro, Caco2 cell monolayers were infected with S. Typhi Ty21a, CVD 908-htrA, and CVD 909 attenuated strains (Figure 2). Wild-type S. Typhi was used as a positive control. Monolayers reached confluence in about 2 weeks, with a baseline TEER between 1200 and 1700 Ω.cm2 (t = 0). As described in our first series of experiments, wild-type S. Typhi induced a significant decline in TEER at all MOIs as early as 2 h post-infection (Figure 2). In contrast, both CVD 908-htrA and CVD 909 mutant strains failed to induce TEER changes at their lowest infection titers (MOI 40:1; Figure 2A). At a MOI of 400:1 (Figure 2B) we observed a decrease in TEER as early as 2 h post-infection that became more pronounced at 4 h when we registered a drop to 842 ± 43.5 Ω.cm2 and 586.75 ± 13.3 Ω.cm2 for CVD 909 and CVD 908-htrA, respectively compared to baseline values (1185.2 ± 40.0 Ω.cm2). Interestingly, 22 h after exposure to these attenuated strains we observed a recovery in TEER values, although the difference with the uninfected monolayer was still significant (Figure 2B).


In vitro Intestinal Mucosal Epithelial Responses to Wild-Type Salmonella Typhi and Attenuated Typhoid Vaccines.

Fiorentino M, Lammers KM, Levine MM, Sztein MB, Fasano A - Front Immunol (2013)

The effect of S. Typhi attenuated strain on the TEER of polarized Caco2 monolayers. Wild-type S. Typhi served as control. (A)Aro mutants-infected monolayers (MOI of 40:1); (B)Aro mutants-infected monolayers (MOI of 400:1). (C)Aro mutants-infected monolayers (MOI of 4000:1). (D) TEER in Caco2 cells infected with Ty21a applied apically at a MOI of 4000:1. Data are expressed as means ± SEM for triplicate samples for all conditions tested. These results are representative of three experiments with similar results. Statistical comparisons over wild-type S. Typhi at the same time point; *p < 0.05 (ANOVA).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3569575&req=5

Figure 2: The effect of S. Typhi attenuated strain on the TEER of polarized Caco2 monolayers. Wild-type S. Typhi served as control. (A)Aro mutants-infected monolayers (MOI of 40:1); (B)Aro mutants-infected monolayers (MOI of 400:1). (C)Aro mutants-infected monolayers (MOI of 4000:1). (D) TEER in Caco2 cells infected with Ty21a applied apically at a MOI of 4000:1. Data are expressed as means ± SEM for triplicate samples for all conditions tested. These results are representative of three experiments with similar results. Statistical comparisons over wild-type S. Typhi at the same time point; *p < 0.05 (ANOVA).
Mentions: To determine the effect of attenuated mutant strains of S. Typhi on mucosal permeability in vitro, Caco2 cell monolayers were infected with S. Typhi Ty21a, CVD 908-htrA, and CVD 909 attenuated strains (Figure 2). Wild-type S. Typhi was used as a positive control. Monolayers reached confluence in about 2 weeks, with a baseline TEER between 1200 and 1700 Ω.cm2 (t = 0). As described in our first series of experiments, wild-type S. Typhi induced a significant decline in TEER at all MOIs as early as 2 h post-infection (Figure 2). In contrast, both CVD 908-htrA and CVD 909 mutant strains failed to induce TEER changes at their lowest infection titers (MOI 40:1; Figure 2A). At a MOI of 400:1 (Figure 2B) we observed a decrease in TEER as early as 2 h post-infection that became more pronounced at 4 h when we registered a drop to 842 ± 43.5 Ω.cm2 and 586.75 ± 13.3 Ω.cm2 for CVD 909 and CVD 908-htrA, respectively compared to baseline values (1185.2 ± 40.0 Ω.cm2). Interestingly, 22 h after exposure to these attenuated strains we observed a recovery in TEER values, although the difference with the uninfected monolayer was still significant (Figure 2B).

Bottom Line: Typhi exhibited alterations in the organization of tight junctions, increased paracellular permeability, and a rapid decrease in Trans-Epithelial Electrical Resistance as early as 4 h post-exposure.We conclude that wild-type S.Typhi causes marked transient alterations of the intestinal mucosa that are more pronounced than those observed with Ty21a or new generation attenuated typhoid vaccine candidates.

View Article: PubMed Central - PubMed

Affiliation: Department of Pediatrics, Mucosal Biology Research Center, University of Maryland School of Medicine Baltimore, MD, USA.

ABSTRACT
Typhoid fever, caused by S. Typhi, is responsible for approximately 200,000 deaths per year worldwide. Little information is available regarding epithelium-bacterial interactions in S. Typhi infection. We have evaluated in vitro the effects of wild-type S. Typhi, the licensed Ty21a typhoid vaccine and the leading strains CVD 908-htrA and CVD 909 vaccine candidates on intestinal barrier function and immune response. Caco2 monolayers infected with wild-type S. Typhi exhibited alterations in the organization of tight junctions, increased paracellular permeability, and a rapid decrease in Trans-Epithelial Electrical Resistance as early as 4 h post-exposure. S. Typhi triggered the secretion of interleukin (IL)-8 and IL-6. Caco2 cells infected with the attenuated strains exhibited a milder pro-inflammatory response with minimal disruption of the barrier integrity. We conclude that wild-type S. Typhi causes marked transient alterations of the intestinal mucosa that are more pronounced than those observed with Ty21a or new generation attenuated typhoid vaccine candidates.

No MeSH data available.


Related in: MedlinePlus