Ligands, such as LPS (data not shown), as elsewhere described [20,21,11]. The maturation of DCs resulted in a tightly regulated production of pro- and anti-inflammatory cytokines, depending on the type of stimuli. In accordance with the tolerogenic phenotype shown in Figure 1A, tol-DC cytokine secretion resulted in significantly higher production of the antiinflammatory cytokine IL-10 (mean = 5106453 pg/ml) compared with either iDCs (68669 pg/ml, p,0.001) or mDCs (51659 pg/ ml, p,0.001) (Figure 1B). The inflammatory cytokines IL-12p70 and IL-23 remained undetectable in the supernatants of either tolDCs or mDCs, which is coherent with the absence to TLR-L on the maturation cocktail [22,23]. In order to confirm these results, we analyzed the transcripts of these cytokines by real-time PCR. mRNA Gracillin biological activity levels for the pro-inflammatory cytokine IL-12p35 were significantly reduced in tol-DCs compared to mDCs (Figure 1C), whereas the RNA levels of IL-10 exhibited a significant six-fold increase in tol-DCs compared with mDCs, thus corroborating our results at the protein level.mDCs. In contrast, T cells exposed to control DCs proliferated and secreted IFN-c to a high degree (Figure 3A). To confirm the capacity of tol-DCs to mitigate effector T cells, tetanus toxoid (TT)-specific T cell lines were re-stimulated with TT loaded or control (non-loaded) mDCs. Whereas T cells primarily exposed to mDCs vigorously responded to TT, as measured by T-cell proliferation and IFN-c production (Figure 3B), those exposed to tol-DCs showed a significantly reduced proliferation and an absolute inability to induce IFN-c during a secondary response to TT-loaded DCs.Tolerogenic DCs are Stable and Resistant to Further StimulationTo address the stability of tol-DCs, dexamethasone and cytokines were carefully washed away and the DCs were restimulated with secondary maturation stimulus. Tol-DCs were refractory to further stimulation with LPS (Figure 4A, data from n = 6 independent experiments) and CD40L (n = 4), maintaining a stable semi-mature phenotype. Interestingly, tol-DCs retained their ability to further produce high levels of IL-10, but failed to generate IL-12 or IL-23 following stimulation with LPS (Figure 4B) data not included for negative IL-12 and IL-23), we did not detect any cytokine after CD40L stimulation. Furthermore, tol-DCs re-challenged with LPS or CD40L were unable to induce a proliferative T-cell response (Figure 4C). In addition, the lower levels of IFN-c cytokine secretion by T cells stimulated with LPS-treated tol-DCs compared with mDCs (mean 633261514 vs 17006700 pg/ml p = 0.07) suggest inhibition of the Th1-type response (Figure 4C).Tolerogenic Response of Dexamethasone-conditioned DCs to Gram-negative 374913-63-0 BacteriaWhole microorganisms contain multiple PAMPs capable of stimulating DCs by different pathways. This capacity exemplifies a more physiological setting, versus the use of restricted TLR agonists or exogenous recombinant cytokines. DCs were incubated with Gram-negative heat-inactivated Escherichia coli (E. coli). Interestingly, the presence of dexamethasone during DCs differentiation profoundly influenced cell maturation, exhibiting strong inhibitory effect on their phenotype (Figure 5A) with significant reduction in CD83, CD86 and MHC class I and II expression, when compared with DCs without E. coli. Importantly, it caused a robust inhibition of pro-inflammatory cytokines (IL-12p70, IL23 and TNF-a), increased IL-10 secretion (Figure 5B), and mo.Ligands, such as LPS (data not shown), as elsewhere described [20,21,11]. The maturation of DCs resulted in a tightly regulated production of pro- and anti-inflammatory cytokines, depending on the type of stimuli. In accordance with the tolerogenic phenotype shown in Figure 1A, tol-DC cytokine secretion resulted in significantly higher production of the antiinflammatory cytokine IL-10 (mean = 5106453 pg/ml) compared with either iDCs (68669 pg/ml, p,0.001) or mDCs (51659 pg/ ml, p,0.001) (Figure 1B). The inflammatory cytokines IL-12p70 and IL-23 remained undetectable in the supernatants of either tolDCs or mDCs, which is coherent with the absence to TLR-L on the maturation cocktail [22,23]. In order to confirm these results, we analyzed the transcripts of these cytokines by real-time PCR. mRNA levels for the pro-inflammatory cytokine IL-12p35 were significantly reduced in tol-DCs compared to mDCs (Figure 1C), whereas the RNA levels of IL-10 exhibited a significant six-fold increase in tol-DCs compared with mDCs, thus corroborating our results at the protein level.mDCs. In contrast, T cells exposed to control DCs proliferated and secreted IFN-c to a high degree (Figure 3A). To confirm the capacity of tol-DCs to mitigate effector T cells, tetanus toxoid (TT)-specific T cell lines were re-stimulated with TT loaded or control (non-loaded) mDCs. Whereas T cells primarily exposed to mDCs vigorously responded to TT, as measured by T-cell proliferation and IFN-c production (Figure 3B), those exposed to tol-DCs showed a significantly reduced proliferation and an absolute inability to induce IFN-c during a secondary response to TT-loaded DCs.Tolerogenic DCs are Stable and Resistant to Further StimulationTo address the stability of tol-DCs, dexamethasone and cytokines were carefully washed away and the DCs were restimulated with secondary maturation stimulus. Tol-DCs were refractory to further stimulation with LPS (Figure 4A, data from n = 6 independent experiments) and CD40L (n = 4), maintaining a stable semi-mature phenotype. Interestingly, tol-DCs retained their ability to further produce high levels of IL-10, but failed to generate IL-12 or IL-23 following stimulation with LPS (Figure 4B) data not included for negative IL-12 and IL-23), we did not detect any cytokine after CD40L stimulation. Furthermore, tol-DCs re-challenged with LPS or CD40L were unable to induce a proliferative T-cell response (Figure 4C). In addition, the lower levels of IFN-c cytokine secretion by T cells stimulated with LPS-treated tol-DCs compared with mDCs (mean 633261514 vs 17006700 pg/ml p = 0.07) suggest inhibition of the Th1-type response (Figure 4C).Tolerogenic Response of Dexamethasone-conditioned DCs to Gram-negative BacteriaWhole microorganisms contain multiple PAMPs capable of stimulating DCs by different pathways. This capacity exemplifies a more physiological setting, versus the use of restricted TLR agonists or exogenous recombinant cytokines. DCs were incubated with Gram-negative heat-inactivated Escherichia coli (E. coli). Interestingly, the presence of dexamethasone during DCs differentiation profoundly influenced cell maturation, exhibiting strong inhibitory effect on their phenotype (Figure 5A) with significant reduction in CD83, CD86 and MHC class I and II expression, when compared with DCs without E. coli. Importantly, it caused a robust inhibition of pro-inflammatory cytokines (IL-12p70, IL23 and TNF-a), increased IL-10 secretion (Figure 5B), and mo.
