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Differential intracellular fate of Burkholderia pseudomallei 844 and Burkholderia thailandensis UE5 in human monocyte-derived dendritic cells and macrophages.

Charoensap J, Utaisincharoen P, Engering A, Sirisinha S - BMC Immunol. (2009)

Bottom Line: The results were compared with those obtained using the Bt-UE5.By contrast, the two bacteria exhibited different growth kinetics in human Mphis, where the intracellular growth of Bt-UE5, but not Bp-844, was significantly suppressed.Both bacteria induced similar host cellular responses, particularly with regard to their ability to bias T cell differentiation toward a Th1 phenotype.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand. cjaruek@yahoo.com

ABSTRACT

Background: Burkholderia pseudomallei (Bp) is a category B biothreat organism that causes a potentially fatal disease in humans and animals, namely melioidosis. Burkholderia thailandensis (Bt) is another naturally occurring species that is very closely related to Bp. However, despite this closely related genotype, Bt is considered avirulent as it does not cause the disease. In the present study, we compared the growth kinetics of B. pseudomallei strain 844 (Bp-844) in human monocyte-derived dendritic cells (MoDCs) and macrophages (Mphis), as well as its ability to stimulate host cell responses with those of B. thailandensis strain UE5 (Bt-UE5).

Results: Primary human MoDCs and Mphis were infected with Bp-844 and its intracellular growth kinetics and ability to induce host cell responses were evaluated. The results were compared with those obtained using the Bt-UE5. In human MoDCs, both bacteria were similar in respect to their ability to survive and replicate intracellularly, induce upregulation of costimulatory molecules and cytokines and bias T helper cell differentiation toward a Th1 phenotype. By contrast, the two bacteria exhibited different growth kinetics in human Mphis, where the intracellular growth of Bt-UE5, but not Bp-844, was significantly suppressed. Moreover, the ability of Mphis to kill Bp-844 was markedly enhanced following stimulation with IFN-gamma.

Conclusion: The data presented showed that while both strains were similar in their ability to survive and replicate in human MoDCs, only Bp-844 could readily replicate in human Mphis. Both bacteria induced similar host cellular responses, particularly with regard to their ability to bias T cell differentiation toward a Th1 phenotype.

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T helper cell differentiation profiles driven by Bp-844- or Bt-UE5-stimulated MoDCs. MoDCs were allowed to mature after priming with PFA-fixed Bp-844 or Bt-UE5 for 24 hr. These matured MoDCs were then co-cultured with allogeneic T cells for approximately 2 weeks as detailed in the Methods section. Afterward, the resting differentiated T cells were restimulated with PMA/ionomycin and their intracellular IL-4 and IFN-γ levels were analyzed by flow cytometry. E. coli LPS, poly I:C and E.coli LPS + PGE2 were used as referencing stimuli for mixed Th1/Th2, Th1 and Th2, respectively. Results (mean and SEM) of the T cell responses from 5 different MoDC donors interacting with a same batch of allogeneic T cells are shown as per cent of responsive positive T cells in A and a scatter plot from one representative donor is shown in B. Circles indicate the predominant Th1 cell population induced by Bp-844 and Bt-UE5.
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Figure 3: T helper cell differentiation profiles driven by Bp-844- or Bt-UE5-stimulated MoDCs. MoDCs were allowed to mature after priming with PFA-fixed Bp-844 or Bt-UE5 for 24 hr. These matured MoDCs were then co-cultured with allogeneic T cells for approximately 2 weeks as detailed in the Methods section. Afterward, the resting differentiated T cells were restimulated with PMA/ionomycin and their intracellular IL-4 and IFN-γ levels were analyzed by flow cytometry. E. coli LPS, poly I:C and E.coli LPS + PGE2 were used as referencing stimuli for mixed Th1/Th2, Th1 and Th2, respectively. Results (mean and SEM) of the T cell responses from 5 different MoDC donors interacting with a same batch of allogeneic T cells are shown as per cent of responsive positive T cells in A and a scatter plot from one representative donor is shown in B. Circles indicate the predominant Th1 cell population induced by Bp-844 and Bt-UE5.

Mentions: We compared the ability of Bp-844-and Bt-UE5-stimulated MoDCs to induce Th1-Th2 differentiation. A MoDC-allogeneic naïve CD4+ co-culture system was employed essentially as described earlier by Bergman et al. (9). MoDCs from 5 different donors that had been exposed to PFA-fixed Bp-844 or Bt-UE5 were incubated with allogeneic T cells and the extent of T-cell polarization was determined (Figure 3A). Scatter plots of flow cytometry analyses from one representative MoDC donor are separately shown in Figure 3B. The results with all 5 donors showed that MoDCs exposed to either of the PFA-fixed bacteria biased toward a Th1 polarization, based on the observation that the majority of T cells in samples that had been exposed to the bacteria produced intracellular IFN-γ which is a characteristic of Th1 cells. In conclusion, stimulation of MoDCs with either Bp-844 or Bt-UE5 induced indistinguishable T-helper cell profiles, i.e., both predominantly induced naïve T cells to differentiate to a Th1 cell population.


Differential intracellular fate of Burkholderia pseudomallei 844 and Burkholderia thailandensis UE5 in human monocyte-derived dendritic cells and macrophages.

Charoensap J, Utaisincharoen P, Engering A, Sirisinha S - BMC Immunol. (2009)

T helper cell differentiation profiles driven by Bp-844- or Bt-UE5-stimulated MoDCs. MoDCs were allowed to mature after priming with PFA-fixed Bp-844 or Bt-UE5 for 24 hr. These matured MoDCs were then co-cultured with allogeneic T cells for approximately 2 weeks as detailed in the Methods section. Afterward, the resting differentiated T cells were restimulated with PMA/ionomycin and their intracellular IL-4 and IFN-γ levels were analyzed by flow cytometry. E. coli LPS, poly I:C and E.coli LPS + PGE2 were used as referencing stimuli for mixed Th1/Th2, Th1 and Th2, respectively. Results (mean and SEM) of the T cell responses from 5 different MoDC donors interacting with a same batch of allogeneic T cells are shown as per cent of responsive positive T cells in A and a scatter plot from one representative donor is shown in B. Circles indicate the predominant Th1 cell population induced by Bp-844 and Bt-UE5.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2683794&req=5

Figure 3: T helper cell differentiation profiles driven by Bp-844- or Bt-UE5-stimulated MoDCs. MoDCs were allowed to mature after priming with PFA-fixed Bp-844 or Bt-UE5 for 24 hr. These matured MoDCs were then co-cultured with allogeneic T cells for approximately 2 weeks as detailed in the Methods section. Afterward, the resting differentiated T cells were restimulated with PMA/ionomycin and their intracellular IL-4 and IFN-γ levels were analyzed by flow cytometry. E. coli LPS, poly I:C and E.coli LPS + PGE2 were used as referencing stimuli for mixed Th1/Th2, Th1 and Th2, respectively. Results (mean and SEM) of the T cell responses from 5 different MoDC donors interacting with a same batch of allogeneic T cells are shown as per cent of responsive positive T cells in A and a scatter plot from one representative donor is shown in B. Circles indicate the predominant Th1 cell population induced by Bp-844 and Bt-UE5.
Mentions: We compared the ability of Bp-844-and Bt-UE5-stimulated MoDCs to induce Th1-Th2 differentiation. A MoDC-allogeneic naïve CD4+ co-culture system was employed essentially as described earlier by Bergman et al. (9). MoDCs from 5 different donors that had been exposed to PFA-fixed Bp-844 or Bt-UE5 were incubated with allogeneic T cells and the extent of T-cell polarization was determined (Figure 3A). Scatter plots of flow cytometry analyses from one representative MoDC donor are separately shown in Figure 3B. The results with all 5 donors showed that MoDCs exposed to either of the PFA-fixed bacteria biased toward a Th1 polarization, based on the observation that the majority of T cells in samples that had been exposed to the bacteria produced intracellular IFN-γ which is a characteristic of Th1 cells. In conclusion, stimulation of MoDCs with either Bp-844 or Bt-UE5 induced indistinguishable T-helper cell profiles, i.e., both predominantly induced naïve T cells to differentiate to a Th1 cell population.

Bottom Line: The results were compared with those obtained using the Bt-UE5.By contrast, the two bacteria exhibited different growth kinetics in human Mphis, where the intracellular growth of Bt-UE5, but not Bp-844, was significantly suppressed.Both bacteria induced similar host cellular responses, particularly with regard to their ability to bias T cell differentiation toward a Th1 phenotype.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Microbiology, Faculty of Science, Mahidol University, Bangkok, Thailand. cjaruek@yahoo.com

ABSTRACT

Background: Burkholderia pseudomallei (Bp) is a category B biothreat organism that causes a potentially fatal disease in humans and animals, namely melioidosis. Burkholderia thailandensis (Bt) is another naturally occurring species that is very closely related to Bp. However, despite this closely related genotype, Bt is considered avirulent as it does not cause the disease. In the present study, we compared the growth kinetics of B. pseudomallei strain 844 (Bp-844) in human monocyte-derived dendritic cells (MoDCs) and macrophages (Mphis), as well as its ability to stimulate host cell responses with those of B. thailandensis strain UE5 (Bt-UE5).

Results: Primary human MoDCs and Mphis were infected with Bp-844 and its intracellular growth kinetics and ability to induce host cell responses were evaluated. The results were compared with those obtained using the Bt-UE5. In human MoDCs, both bacteria were similar in respect to their ability to survive and replicate intracellularly, induce upregulation of costimulatory molecules and cytokines and bias T helper cell differentiation toward a Th1 phenotype. By contrast, the two bacteria exhibited different growth kinetics in human Mphis, where the intracellular growth of Bt-UE5, but not Bp-844, was significantly suppressed. Moreover, the ability of Mphis to kill Bp-844 was markedly enhanced following stimulation with IFN-gamma.

Conclusion: The data presented showed that while both strains were similar in their ability to survive and replicate in human MoDCs, only Bp-844 could readily replicate in human Mphis. Both bacteria induced similar host cellular responses, particularly with regard to their ability to bias T cell differentiation toward a Th1 phenotype.

Show MeSH
Related in: MedlinePlus