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Bordetella pertussis commits human dendritic cells to promote a Th1/Th17 response through the activity of adenylate cyclase toxin and MAPK-pathways.

Fedele G, Spensieri F, Palazzo R, Nasso M, Cheung GY, Coote JG, Ausiello CM - PLoS ONE (2010)

Bottom Line: B. pertussis-treated MDDC promoted a mixed Th1/Th17 polarization, and the activity of CyaA altered the Th1/Th17 balance, enhancing Th17 and limiting Th1 expansion.We also demonstrated that Th1 effectors are induced by B. pertussis-MDDC in the absence of IL-12p70 through an ERK1/2 dependent mechanism, and that p38 MAPK is essential for MDDC-driven Th17 expansion.The data suggest that CyaA mediates an escape strategy for the bacterium, since it reduces Th1 immunity and increases Th17 responses thought to be responsible, when the response is exacerbated, for enhanced lung inflammation and injury.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.

ABSTRACT
The complex pathology of B. pertussis infection is due to multiple virulence factors having disparate effects on different cell types. We focused our investigation on the ability of B. pertussis to modulate host immunity, in particular on the role played by adenylate cyclase toxin (CyaA), an important virulence factor of B. pertussis. As a tool, we used human monocyte derived dendritic cells (MDDC), an ex vivo model useful for the evaluation of the regulatory potential of DC on T cell immune responses. The work compared MDDC functions after encounter with wild-type B. pertussis (BpWT) or a mutant lacking CyaA (BpCyaA-), or the BpCyaA- strain supplemented with either the fully functional CyaA or a derivative, CyaA*, lacking adenylate cyclase activity. As a first step, MDDC maturation, cytokine production, and modulation of T helper cell polarization were evaluated. As a second step, engagement of Toll-like receptors (TLR) 2 and TLR4 by B. pertussis and the signaling events connected to this were analyzed. These approaches allowed us to demonstrate that CyaA expressed by B. pertussis strongly interferes with DC functions, by reducing the expression of phenotypic markers and immunomodulatory cytokines, and blocking IL-12p70 production. B. pertussis-treated MDDC promoted a mixed Th1/Th17 polarization, and the activity of CyaA altered the Th1/Th17 balance, enhancing Th17 and limiting Th1 expansion. We also demonstrated that Th1 effectors are induced by B. pertussis-MDDC in the absence of IL-12p70 through an ERK1/2 dependent mechanism, and that p38 MAPK is essential for MDDC-driven Th17 expansion. The data suggest that CyaA mediates an escape strategy for the bacterium, since it reduces Th1 immunity and increases Th17 responses thought to be responsible, when the response is exacerbated, for enhanced lung inflammation and injury.

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Th polarization.MDDC either untreated (none) or treated with BpWT or BpCyaA− for 48 h were co-cultured with purified T cells as described in Methods section. On day 12, supernatants were collected and secreted cytokines were measured by ELISA. Results are expressed as mean ± SE of eight independent experiments performed with MDDC and T cells obtained from different donors. * p<0.05 vs none; ° p<0.05 vs BpWT; ‡ p<0.05 vs BpCyaA−.
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pone-0008734-g002: Th polarization.MDDC either untreated (none) or treated with BpWT or BpCyaA− for 48 h were co-cultured with purified T cells as described in Methods section. On day 12, supernatants were collected and secreted cytokines were measured by ELISA. Results are expressed as mean ± SE of eight independent experiments performed with MDDC and T cells obtained from different donors. * p<0.05 vs none; ° p<0.05 vs BpWT; ‡ p<0.05 vs BpCyaA−.

Mentions: Considering the cytokine profile induced by B. pertussis in MDDC, we analyzed their capacity to polarize purified T lymphocytes, and, in particular, the possibility of Th17 induction/expansion. Figure 2 shows that BpWT -treated MDDC drove IFNγ- and IL-17 -producing Th effector cells. Remarkably, in view of the findings in the previous section, when T cells were co-cultured with BpCyaA− -treated MDDC, a significant decrease of IL-17 -producing cells was observed, along with a significant increase of IFNγ -producing cells. The addition of CyaA to BpCyaA− -treated MDDC reverted the polarization profile to that induced by BpWT and IL-17 -producing Th cells were enhanced, while those producing IFNγ significantly decreased. CyaA* did not cause any significant alteration of the polarization profile induced by BpCyaA− -treated MDDC (Figure 2). Th2 polarization, assessed by measuring IL-5 release, was significantly reduced when MDDC were treated with both B. pertussis strains, with respect to untreated MDDC.


Bordetella pertussis commits human dendritic cells to promote a Th1/Th17 response through the activity of adenylate cyclase toxin and MAPK-pathways.

Fedele G, Spensieri F, Palazzo R, Nasso M, Cheung GY, Coote JG, Ausiello CM - PLoS ONE (2010)

Th polarization.MDDC either untreated (none) or treated with BpWT or BpCyaA− for 48 h were co-cultured with purified T cells as described in Methods section. On day 12, supernatants were collected and secreted cytokines were measured by ELISA. Results are expressed as mean ± SE of eight independent experiments performed with MDDC and T cells obtained from different donors. * p<0.05 vs none; ° p<0.05 vs BpWT; ‡ p<0.05 vs BpCyaA−.
© Copyright Policy
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2806909&req=5

pone-0008734-g002: Th polarization.MDDC either untreated (none) or treated with BpWT or BpCyaA− for 48 h were co-cultured with purified T cells as described in Methods section. On day 12, supernatants were collected and secreted cytokines were measured by ELISA. Results are expressed as mean ± SE of eight independent experiments performed with MDDC and T cells obtained from different donors. * p<0.05 vs none; ° p<0.05 vs BpWT; ‡ p<0.05 vs BpCyaA−.
Mentions: Considering the cytokine profile induced by B. pertussis in MDDC, we analyzed their capacity to polarize purified T lymphocytes, and, in particular, the possibility of Th17 induction/expansion. Figure 2 shows that BpWT -treated MDDC drove IFNγ- and IL-17 -producing Th effector cells. Remarkably, in view of the findings in the previous section, when T cells were co-cultured with BpCyaA− -treated MDDC, a significant decrease of IL-17 -producing cells was observed, along with a significant increase of IFNγ -producing cells. The addition of CyaA to BpCyaA− -treated MDDC reverted the polarization profile to that induced by BpWT and IL-17 -producing Th cells were enhanced, while those producing IFNγ significantly decreased. CyaA* did not cause any significant alteration of the polarization profile induced by BpCyaA− -treated MDDC (Figure 2). Th2 polarization, assessed by measuring IL-5 release, was significantly reduced when MDDC were treated with both B. pertussis strains, with respect to untreated MDDC.

Bottom Line: B. pertussis-treated MDDC promoted a mixed Th1/Th17 polarization, and the activity of CyaA altered the Th1/Th17 balance, enhancing Th17 and limiting Th1 expansion.We also demonstrated that Th1 effectors are induced by B. pertussis-MDDC in the absence of IL-12p70 through an ERK1/2 dependent mechanism, and that p38 MAPK is essential for MDDC-driven Th17 expansion.The data suggest that CyaA mediates an escape strategy for the bacterium, since it reduces Th1 immunity and increases Th17 responses thought to be responsible, when the response is exacerbated, for enhanced lung inflammation and injury.

View Article: PubMed Central - PubMed

Affiliation: Department of Infectious, Parasitic and Immune-Mediated Diseases, Istituto Superiore di Sanità, Rome, Italy.

ABSTRACT
The complex pathology of B. pertussis infection is due to multiple virulence factors having disparate effects on different cell types. We focused our investigation on the ability of B. pertussis to modulate host immunity, in particular on the role played by adenylate cyclase toxin (CyaA), an important virulence factor of B. pertussis. As a tool, we used human monocyte derived dendritic cells (MDDC), an ex vivo model useful for the evaluation of the regulatory potential of DC on T cell immune responses. The work compared MDDC functions after encounter with wild-type B. pertussis (BpWT) or a mutant lacking CyaA (BpCyaA-), or the BpCyaA- strain supplemented with either the fully functional CyaA or a derivative, CyaA*, lacking adenylate cyclase activity. As a first step, MDDC maturation, cytokine production, and modulation of T helper cell polarization were evaluated. As a second step, engagement of Toll-like receptors (TLR) 2 and TLR4 by B. pertussis and the signaling events connected to this were analyzed. These approaches allowed us to demonstrate that CyaA expressed by B. pertussis strongly interferes with DC functions, by reducing the expression of phenotypic markers and immunomodulatory cytokines, and blocking IL-12p70 production. B. pertussis-treated MDDC promoted a mixed Th1/Th17 polarization, and the activity of CyaA altered the Th1/Th17 balance, enhancing Th17 and limiting Th1 expansion. We also demonstrated that Th1 effectors are induced by B. pertussis-MDDC in the absence of IL-12p70 through an ERK1/2 dependent mechanism, and that p38 MAPK is essential for MDDC-driven Th17 expansion. The data suggest that CyaA mediates an escape strategy for the bacterium, since it reduces Th1 immunity and increases Th17 responses thought to be responsible, when the response is exacerbated, for enhanced lung inflammation and injury.

Show MeSH
Related in: MedlinePlus