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The B subunit of Escherichia coli heat-labile toxin alters the development and antigen-presenting capacity of dendritic cells.

Ji J, Griffiths KL, Milburn PJ, Hirst TR, O'Neill HC - J. Cell. Mol. Med. (2015)

Bottom Line: In this respect, the in vivo effect of EtxB differs from that of the highly inflammatory mediator lipopolysaccharide.In terms of the in vivo effect of EtxB on CD4 and CD8 T cell responses in mice, the interaction of EtxB directly with DC was demonstrated following conditional depletion of CD11c(+) DC.In summary, all results are consistent with EtxB displaying adjuvant ability by enhancing the turnover of DC in spleen, leading to newly mature myeloid and DC in spleen, thereby increasing DC capacity to perform as antigen-presenting cells on encounter with T cells.

View Article: PubMed Central - PubMed

Affiliation: Research School of Biology, Australian National University, Canberra, ACT, Australia.

No MeSH data available.


Related in: MedlinePlus

Effect of EtxB on DC survival and maturation in vitro. Spleens of mice were harvested, RBC were lysed and enriched for CD11c+ cells. Cells were cultured (5 × 106 cells/ml) for 12 hrs with either 10 μg/ml EtxB, 10 ng/ml LPS, 10 μg/ml HI EtxB, a combination of EtxB and LPS, or medium as a control (nil). Cells were stained with antibodies to CD11c, CD11b, CD8, MHC-II, CD80 and CD86, or isotype control antibodies, prior to flow cytometric analysis. cDCs and pDCs were gated on the basis of CD11c, CD11b, CD8 and MHC-II expression as described in Figure1. Cell viability was measured by staining the total cell population with propidium iodide (PI). Expression of MHC-II is shown as median fluorescent intensity (MFI). Data are presented as mean ± SE of replicates shown as crosshairs. Results from this experiment are reflective of three similar experiments. Significantly different comparisons at P ≤ 0.05 and P ≤ 0.01 shown by * and ** respectively.
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fig03: Effect of EtxB on DC survival and maturation in vitro. Spleens of mice were harvested, RBC were lysed and enriched for CD11c+ cells. Cells were cultured (5 × 106 cells/ml) for 12 hrs with either 10 μg/ml EtxB, 10 ng/ml LPS, 10 μg/ml HI EtxB, a combination of EtxB and LPS, or medium as a control (nil). Cells were stained with antibodies to CD11c, CD11b, CD8, MHC-II, CD80 and CD86, or isotype control antibodies, prior to flow cytometric analysis. cDCs and pDCs were gated on the basis of CD11c, CD11b, CD8 and MHC-II expression as described in Figure1. Cell viability was measured by staining the total cell population with propidium iodide (PI). Expression of MHC-II is shown as median fluorescent intensity (MFI). Data are presented as mean ± SE of replicates shown as crosshairs. Results from this experiment are reflective of three similar experiments. Significantly different comparisons at P ≤ 0.05 and P ≤ 0.01 shown by * and ** respectively.

Mentions: EtxB increased cell survival in in vitro culture, while LPS showed no specific effect on viability within 12 hrs (Fig.3). As cell survival was reduced following heat inactivation of EtxB, the effect seen must be specific for EtxB. Cultures of cells treated with EtxB or EtxB + LPS showed significantly lower expression of MHC-II compared with other cultures (Fig.3). Expression levels of the activation markers CD80 and CD86 were also reduced significantly after the culture of cells with EtxB, with and without LPS (Fig.4). These results could be interpreted to mean that EtxB acts to reduce the turnover and activation of mature DC resulting in higher numbers of immature DC. This could have an adjuvant effect by maintaining DC, as well as their antigen-presenting capacity for a longer period. The absence of any effect of LPS on DC present in spleen contrasts with the known effect of LPS in driving the development of DC from precursors or immature DC. However, this LPS effect is not evident within a 12-hr assay.


The B subunit of Escherichia coli heat-labile toxin alters the development and antigen-presenting capacity of dendritic cells.

Ji J, Griffiths KL, Milburn PJ, Hirst TR, O'Neill HC - J. Cell. Mol. Med. (2015)

Effect of EtxB on DC survival and maturation in vitro. Spleens of mice were harvested, RBC were lysed and enriched for CD11c+ cells. Cells were cultured (5 × 106 cells/ml) for 12 hrs with either 10 μg/ml EtxB, 10 ng/ml LPS, 10 μg/ml HI EtxB, a combination of EtxB and LPS, or medium as a control (nil). Cells were stained with antibodies to CD11c, CD11b, CD8, MHC-II, CD80 and CD86, or isotype control antibodies, prior to flow cytometric analysis. cDCs and pDCs were gated on the basis of CD11c, CD11b, CD8 and MHC-II expression as described in Figure1. Cell viability was measured by staining the total cell population with propidium iodide (PI). Expression of MHC-II is shown as median fluorescent intensity (MFI). Data are presented as mean ± SE of replicates shown as crosshairs. Results from this experiment are reflective of three similar experiments. Significantly different comparisons at P ≤ 0.05 and P ≤ 0.01 shown by * and ** respectively.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4549052&req=5

fig03: Effect of EtxB on DC survival and maturation in vitro. Spleens of mice were harvested, RBC were lysed and enriched for CD11c+ cells. Cells were cultured (5 × 106 cells/ml) for 12 hrs with either 10 μg/ml EtxB, 10 ng/ml LPS, 10 μg/ml HI EtxB, a combination of EtxB and LPS, or medium as a control (nil). Cells were stained with antibodies to CD11c, CD11b, CD8, MHC-II, CD80 and CD86, or isotype control antibodies, prior to flow cytometric analysis. cDCs and pDCs were gated on the basis of CD11c, CD11b, CD8 and MHC-II expression as described in Figure1. Cell viability was measured by staining the total cell population with propidium iodide (PI). Expression of MHC-II is shown as median fluorescent intensity (MFI). Data are presented as mean ± SE of replicates shown as crosshairs. Results from this experiment are reflective of three similar experiments. Significantly different comparisons at P ≤ 0.05 and P ≤ 0.01 shown by * and ** respectively.
Mentions: EtxB increased cell survival in in vitro culture, while LPS showed no specific effect on viability within 12 hrs (Fig.3). As cell survival was reduced following heat inactivation of EtxB, the effect seen must be specific for EtxB. Cultures of cells treated with EtxB or EtxB + LPS showed significantly lower expression of MHC-II compared with other cultures (Fig.3). Expression levels of the activation markers CD80 and CD86 were also reduced significantly after the culture of cells with EtxB, with and without LPS (Fig.4). These results could be interpreted to mean that EtxB acts to reduce the turnover and activation of mature DC resulting in higher numbers of immature DC. This could have an adjuvant effect by maintaining DC, as well as their antigen-presenting capacity for a longer period. The absence of any effect of LPS on DC present in spleen contrasts with the known effect of LPS in driving the development of DC from precursors or immature DC. However, this LPS effect is not evident within a 12-hr assay.

Bottom Line: In this respect, the in vivo effect of EtxB differs from that of the highly inflammatory mediator lipopolysaccharide.In terms of the in vivo effect of EtxB on CD4 and CD8 T cell responses in mice, the interaction of EtxB directly with DC was demonstrated following conditional depletion of CD11c(+) DC.In summary, all results are consistent with EtxB displaying adjuvant ability by enhancing the turnover of DC in spleen, leading to newly mature myeloid and DC in spleen, thereby increasing DC capacity to perform as antigen-presenting cells on encounter with T cells.

View Article: PubMed Central - PubMed

Affiliation: Research School of Biology, Australian National University, Canberra, ACT, Australia.

No MeSH data available.


Related in: MedlinePlus