Peripheral blood mononuclear cells (PBMCs) were CP-690550 mw isolated by Ficoll density gradient centrifugation of blood

obtained from buffy coats from healthy donors. PBMCs (200 × 106 cells/ml) were incubated for 2 h at 37°C in 5% CO2 in 25 cm2 flask plates. After washing, the adherent monocytes were cultured in the presence of 500 U/ml of IL-4 and 1000 U/ml of GM-CSF in RPMI-1640 medium with 10% human serum at 37°C in a humidified atmosphere of 5% CO2, obtaining 90% DC purity at day 7. ABC inhibitors were added once after 48 h of monocyte isolation: MDR1 inhibitor (PSC833, 5 μM), MRP1 and MRP2 inhibitors (MK571, 50 μM) and probenecid (PBN), 2·5 μM. Cells were kept at 37°C in a humidified atmosphere with 5% CO2. Medium with supplements and inhibitors was changed every second day and prior to experiments. The gating of DC populations was validated in our previous selleck screening library study [8]. Lymphocytes were obtained by Ficoll-Percoll gradient and purified by non-adherence. Immature DCs (2 × 106 cells/ml RPMI 10% human serum) were exposed at day 5 to hypoxia conditions for 48 h [8]. Hypoxic (0·5% oxygen) conditions were generated at day 5, exposing iDCs to hypoxia (0·5% O2, 5% CO2) in a hypoxia atmosphere-controlled incubator (Binder), keeping cells unmanipulated for 48 h,

thereby avoiding O2 pressure changes. To compare with a standard stimulus for DCs maturation, LPS (2 μg/ml) was added for 24 h at day 6 after PBMC isolation. Flow cytometry (fluorescence-activated cell sorting: FACS) analysis was performed using a FACS Canto and diva software (Becton Dickinson). The study subpopulation was defined using different cell markers: CD3 for lymphocytes, CD14 for monocytes, CD20 for B cells and CD56 to stain natural killer (NK) cells. Thereafter, FACS was performed at day 7 of DCs to assess mean fluorescence and expression of mature cell phenotype. CD14, CD11c and CD123 were used to identify the DC nature and different markers were used to define the mature population of DCs (mDCs) (CD40/CD80/CD83/CD86/CD54/HLA-DR). To assess the DC phenotype, we

used the markers according to standard MYO10 methods in the literature for DCs [18-20]. Incubation was carried out at 4°C for 30 min. Apoptosis was measured by annexin-V using flow cytometry. Intracellular HIF-1α was assessed by flow cytometry (FACS Canto; Becton Dickinson). DCs were identified with two membrane markers as HLA-DR+ and CD11c+. After phenotyping, cells were permeabilized with saponine buffer (Sigma, Madrid) and labelled with HIF-1α or isotype control (R&D Systems). Intracellular HIF-1α was analysed in the double-positive region for HLA-DR+ and CD11c+. To assess Pgp and MRP1 expression in iDCs and mDCs, double-surface immunostaining and dual-colour flow cytometry of freshly isolated PBMCs were carried out following incubation overnight at 37°C in human serum.