Following this treatment, iDCs were LPS pulsed and cultured for additional 24 h. As reported above, LPS increased expression of both CD80 and CD40 surface markers on DCs (Figure 4A-B). LY3023414 Pretreatment of DCs with supernatant from MODE-K monolayers (SupMODE) down-regulated the expression of these markers (Figure 4C). However, down-regulation was completely reversed when MODE-K cells were stimulated with TNF-α (Figure 4D). Interestingly, bacteria-conditioned supernatants from MODE-K

cells induced a further increase in the expression of the co-stimulatory markers (Figure 4E-F). The data reported in Figure 4G and H clearly showed that inductive effects also resulted from metabolites secreted into the medium by both bacterial strains (SupOLL2809 and SupL13-Ia). Direct challenge with bacteria was much less effective than challenge with the bacterial metabolites in inducing the expression of CD80 and CD40 on DCs following LPS stimulation (Figure 4I-J). We next examined the effects of conditioned

media on the cytokine profile. Interestingly, SupMODE down-regulated IL-12 expression and markedly induced TNF-α and IL-10 in LPS-pulsed iDCs (Figure 5); this effect was dramatically reduced when MODE-K cells were treated with TNF-α. Notably, media from bacteria-conditioned VS-4718 supplier MODE-K cell cultures completely suppressed the expression of all examined cytokines. A similar effect was reproduced when DCs were treated with SupOLL2809 and SupL13-Ia (Figure 5). Baseline levels of IL-12, IL-10 and TNF-α in the selleck kinase inhibitor various supernatants were undetectable, with the exception of TNF-α- > SupMODE where TNF-α levels were not significantly different from those found in the control (iDCs alone; data not shown). This indicated that added TNF-α (5 μg l-1) was mainly metabolized/degraded after 24 h in this sample. Direct incubation of iDCs with

irradiated bacteria dramatically enhanced the secretion of all examined cytokines, after LPS pulse, at levels comparable to those reported in Figure 2 (data not shown). Figure 4 Expression of co-stimulatory markers CD80 and CD40 on the surface of DCs conditioned with culture medium from MODE-K cells ±  L. gasseri OLL2809/L13-Ia. Before a 6-h LPS pulse, iDCs were challenged for 24 h with medium from: untreated MODE-K Loperamide cell culture (SupMODE, C); MODE-K cells following TNF-α stimulation (D); MODE-K cells following probiotic co-incubation (E and F); irradiated OLL2809 or L13-Ia (24 h incubation; SupOLL2809 and SupL13-Ia, G and H). iDCs were also directly challenged for 24 h with irradiated bacteria (I and J). iDCs (A) and untreated mDCs (B) were used as controls. DCs were stained for CD40 and CD80 and analyzed by FACS. Data were collected from ungated cells and are representative of three independent experiments. Figure 5 Cytokine production by DCs conditioned with culture medium from MODE-K cells ±  L. gasseri OLL2809/L13-Ia. iDCs were challenged for 24 h with the same media described in Figure 4 and then LPS pulsed.