Limits...
Caspase-1 Dependent IL-1β Secretion and Antigen-Specific T-Cell Activation by the Novel Adjuvant, PCEP.

Awate S, Eng NF, Gerdts V, Babiuk LA, Mutwiri G - Vaccines (Basel) (2014)

Bottom Line: Caspase inhibitor YVAD-fmk-treated splenic DCs showed significantly reduced IL-1β and IL-18 secretion in response to PCEP stimulation.Further, PCEP had no effect on the expression of MHC class II or co-stimulatory molecules, CD86 and CD40, suggesting that PCEP does not induce DC maturation.We conclude that PCEP activates innate immunity, leading to increased antigen-specific T-cell responses.

View Article: PubMed Central - PubMed

Affiliation: Vaccinology and Immunotherapeutics program, School of Public Health, 107 Wiggins Road, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada. sunita.awate@usask.ca.

ABSTRACT
The potent adjuvant activity of the novel adjuvant, poly[di(sodiumcarboxylatoethylphenoxy)phosphazene] (PCEP), with various antigens has been reported previously. However, very little is known about its mechanisms of action. We have recently reported that intramuscular injection of PCEP induces NLRP3, an inflammasome receptor gene, and inflammatory cytokines, including IL-1β and IL-18, in mouse muscle tissue. Caspase-1 is required for the processing of pro-forms of IL-1β and IL-18 into mature forms and is a critical constituent of the NLRP3 inflammasome. Hence, in the present study, we investigated the role of caspase-1 in the secretion of IL-1β and IL-18 in PCEP-stimulated splenic dendritic cells (DCs). Caspase inhibitor YVAD-fmk-treated splenic DCs showed significantly reduced IL-1β and IL-18 secretion in response to PCEP stimulation. Further, PCEP had no effect on the expression of MHC class II or co-stimulatory molecules, CD86 and CD40, suggesting that PCEP does not induce DC maturation. However, PCEP directly activated B-cells to induce significant production of IgM. In addition, PCEP+ovalbumin (OVA) immunized mice showed significantly increased production of antigen-specific IFN-γ by CD4⁺ and CD8⁺ T-cells. We conclude that PCEP activates innate immunity, leading to increased antigen-specific T-cell responses.

No MeSH data available.


Related in: MedlinePlus

PCEP does not induce MHC class II and co-stimulatory molecules expression in vitro. Bone marrow-derived dendritic cells (BMDCs) (1 × 106 cells/mL) were incubated with media, PCEP (50 μg/mL) or lipopolysaccharide (LPS) (100 ng/mL) for 24 h. Cells were stained with MHC class II, CD 86 and CD40 antibodies and analyzed by flow cytometry. The overlay histograms show the % of maximum cells positive for MHC class II, CD86 or CD40 in PCEP- and LPS-treated BMDCs. The blue shaded area represents media control, and the green overlay line represents LPS- and PCEP-treated BMDCs.1.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4494223&req=5

vaccines-02-00500-f003: PCEP does not induce MHC class II and co-stimulatory molecules expression in vitro. Bone marrow-derived dendritic cells (BMDCs) (1 × 106 cells/mL) were incubated with media, PCEP (50 μg/mL) or lipopolysaccharide (LPS) (100 ng/mL) for 24 h. Cells were stained with MHC class II, CD 86 and CD40 antibodies and analyzed by flow cytometry. The overlay histograms show the % of maximum cells positive for MHC class II, CD86 or CD40 in PCEP- and LPS-treated BMDCs. The blue shaded area represents media control, and the green overlay line represents LPS- and PCEP-treated BMDCs.1.

Mentions: PCEP did not induce significant MHC class II and co-stimulatory molecules CD86 and CD40 expression in BMDCs compared to negative controls (Figure 3). In contrast, MHC class II, CD86 and CD40 molecules were highly expressed in LPS-treated BMDCs (Figure 3).


Caspase-1 Dependent IL-1β Secretion and Antigen-Specific T-Cell Activation by the Novel Adjuvant, PCEP.

Awate S, Eng NF, Gerdts V, Babiuk LA, Mutwiri G - Vaccines (Basel) (2014)

PCEP does not induce MHC class II and co-stimulatory molecules expression in vitro. Bone marrow-derived dendritic cells (BMDCs) (1 × 106 cells/mL) were incubated with media, PCEP (50 μg/mL) or lipopolysaccharide (LPS) (100 ng/mL) for 24 h. Cells were stained with MHC class II, CD 86 and CD40 antibodies and analyzed by flow cytometry. The overlay histograms show the % of maximum cells positive for MHC class II, CD86 or CD40 in PCEP- and LPS-treated BMDCs. The blue shaded area represents media control, and the green overlay line represents LPS- and PCEP-treated BMDCs.1.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494223&req=5

vaccines-02-00500-f003: PCEP does not induce MHC class II and co-stimulatory molecules expression in vitro. Bone marrow-derived dendritic cells (BMDCs) (1 × 106 cells/mL) were incubated with media, PCEP (50 μg/mL) or lipopolysaccharide (LPS) (100 ng/mL) for 24 h. Cells were stained with MHC class II, CD 86 and CD40 antibodies and analyzed by flow cytometry. The overlay histograms show the % of maximum cells positive for MHC class II, CD86 or CD40 in PCEP- and LPS-treated BMDCs. The blue shaded area represents media control, and the green overlay line represents LPS- and PCEP-treated BMDCs.1.
Mentions: PCEP did not induce significant MHC class II and co-stimulatory molecules CD86 and CD40 expression in BMDCs compared to negative controls (Figure 3). In contrast, MHC class II, CD86 and CD40 molecules were highly expressed in LPS-treated BMDCs (Figure 3).

Bottom Line: Caspase inhibitor YVAD-fmk-treated splenic DCs showed significantly reduced IL-1β and IL-18 secretion in response to PCEP stimulation.Further, PCEP had no effect on the expression of MHC class II or co-stimulatory molecules, CD86 and CD40, suggesting that PCEP does not induce DC maturation.We conclude that PCEP activates innate immunity, leading to increased antigen-specific T-cell responses.

View Article: PubMed Central - PubMed

Affiliation: Vaccinology and Immunotherapeutics program, School of Public Health, 107 Wiggins Road, University of Saskatchewan, Saskatoon, SK S7N 5E5, Canada. sunita.awate@usask.ca.

ABSTRACT
The potent adjuvant activity of the novel adjuvant, poly[di(sodiumcarboxylatoethylphenoxy)phosphazene] (PCEP), with various antigens has been reported previously. However, very little is known about its mechanisms of action. We have recently reported that intramuscular injection of PCEP induces NLRP3, an inflammasome receptor gene, and inflammatory cytokines, including IL-1β and IL-18, in mouse muscle tissue. Caspase-1 is required for the processing of pro-forms of IL-1β and IL-18 into mature forms and is a critical constituent of the NLRP3 inflammasome. Hence, in the present study, we investigated the role of caspase-1 in the secretion of IL-1β and IL-18 in PCEP-stimulated splenic dendritic cells (DCs). Caspase inhibitor YVAD-fmk-treated splenic DCs showed significantly reduced IL-1β and IL-18 secretion in response to PCEP stimulation. Further, PCEP had no effect on the expression of MHC class II or co-stimulatory molecules, CD86 and CD40, suggesting that PCEP does not induce DC maturation. However, PCEP directly activated B-cells to induce significant production of IgM. In addition, PCEP+ovalbumin (OVA) immunized mice showed significantly increased production of antigen-specific IFN-γ by CD4⁺ and CD8⁺ T-cells. We conclude that PCEP activates innate immunity, leading to increased antigen-specific T-cell responses.

No MeSH data available.


Related in: MedlinePlus