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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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Host cell responses upon Bp-844 and Bt-UE5 infection. Mφs (A and C) and MoDCs (B and D) were infected with Bp-844 or Bt-UE5 at MOI of 1 for 24 hr and 250 μg/ml kanamycin was added 2 hr after infection. Expression levels of CD86, CD80 and CD11b of Mφs (A) and CD86, CD83 and CD40 of MoDCs (B) on the cell surface were determined with flow cytometry and the results are shown as mean and SEM. Cytokines in supernatants of infected Mφs (C) and infected MoDCs (D) were measured by ELISA and results are shown as mean and SEM, with each symbol representing the level from individual donor. E. coli LPS (1 μg/ml) and PBS were used as controls. Number in parenthesis indicates the number of donors for each experiment. MFI = mean fluorescence intensity.
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Figure 2: Host cell responses upon Bp-844 and Bt-UE5 infection. Mφs (A and C) and MoDCs (B and D) were infected with Bp-844 or Bt-UE5 at MOI of 1 for 24 hr and 250 μg/ml kanamycin was added 2 hr after infection. Expression levels of CD86, CD80 and CD11b of Mφs (A) and CD86, CD83 and CD40 of MoDCs (B) on the cell surface were determined with flow cytometry and the results are shown as mean and SEM. Cytokines in supernatants of infected Mφs (C) and infected MoDCs (D) were measured by ELISA and results are shown as mean and SEM, with each symbol representing the level from individual donor. E. coli LPS (1 μg/ml) and PBS were used as controls. Number in parenthesis indicates the number of donors for each experiment. MFI = mean fluorescence intensity.

Mentions: Given the different fates on intracellular bacterial survival profiles noted above, it was of interest to examine the effect of bacterial infection on the production of host costimulatory molecules, surface markers and cytokines. Exposure of MoDCs to Bp-844 and Bt-UE5at a MOI of 1 for 24 hr readily induced cell maturation as judged by significant increases in the levels of the maturation marker, CD83 (Figure 2B). Under the same conditions, both Bp-844 and Bt-UE5 induced upregulation of the costimulatory molecule, CD86, in MoDCs and Mφs (Figure 2A and 2B). The effect of bacterial infection on the upregulation of other costimulatory molecules varied. For example, while the levels of CD40 (Figure 2B) and CD80 (data not shown) in MoDCs also increased, it was rather surprising to observe that infection of Mφs with either Bp-844 or Bt-UE5 actually caused a reduction in the levels of CD80 and CD11b (Figure 2A). The reduction noted with the Mφs is unlikely to be related to a technical artifact because when compared with the background MFI (mean fluorescence intensity) obtained with PBS, Escherichia coli LPS also slightly depressed CD11b expression, a finding that is consistent with earlier reports by other investigators using some other human Mφmodels [7,8].


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)

Host cell responses upon Bp-844 and Bt-UE5 infection. Mφs (A and C) and MoDCs (B and D) were infected with Bp-844 or Bt-UE5 at MOI of 1 for 24 hr and 250 μg/ml kanamycin was added 2 hr after infection. Expression levels of CD86, CD80 and CD11b of Mφs (A) and CD86, CD83 and CD40 of MoDCs (B) on the cell surface were determined with flow cytometry and the results are shown as mean and SEM. Cytokines in supernatants of infected Mφs (C) and infected MoDCs (D) were measured by ELISA and results are shown as mean and SEM, with each symbol representing the level from individual donor. E. coli LPS (1 μg/ml) and PBS were used as controls. Number in parenthesis indicates the number of donors for each experiment. MFI = mean fluorescence intensity.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 2: Host cell responses upon Bp-844 and Bt-UE5 infection. Mφs (A and C) and MoDCs (B and D) were infected with Bp-844 or Bt-UE5 at MOI of 1 for 24 hr and 250 μg/ml kanamycin was added 2 hr after infection. Expression levels of CD86, CD80 and CD11b of Mφs (A) and CD86, CD83 and CD40 of MoDCs (B) on the cell surface were determined with flow cytometry and the results are shown as mean and SEM. Cytokines in supernatants of infected Mφs (C) and infected MoDCs (D) were measured by ELISA and results are shown as mean and SEM, with each symbol representing the level from individual donor. E. coli LPS (1 μg/ml) and PBS were used as controls. Number in parenthesis indicates the number of donors for each experiment. MFI = mean fluorescence intensity.
Mentions: Given the different fates on intracellular bacterial survival profiles noted above, it was of interest to examine the effect of bacterial infection on the production of host costimulatory molecules, surface markers and cytokines. Exposure of MoDCs to Bp-844 and Bt-UE5at a MOI of 1 for 24 hr readily induced cell maturation as judged by significant increases in the levels of the maturation marker, CD83 (Figure 2B). Under the same conditions, both Bp-844 and Bt-UE5 induced upregulation of the costimulatory molecule, CD86, in MoDCs and Mφs (Figure 2A and 2B). The effect of bacterial infection on the upregulation of other costimulatory molecules varied. For example, while the levels of CD40 (Figure 2B) and CD80 (data not shown) in MoDCs also increased, it was rather surprising to observe that infection of Mφs with either Bp-844 or Bt-UE5 actually caused a reduction in the levels of CD80 and CD11b (Figure 2A). The reduction noted with the Mφs is unlikely to be related to a technical artifact because when compared with the background MFI (mean fluorescence intensity) obtained with PBS, Escherichia coli LPS also slightly depressed CD11b expression, a finding that is consistent with earlier reports by other investigators using some other human Mφmodels [7,8].

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