Central to DC functioning is their ability to take up antigens. To directly compare the endocytic activity of MoDCs and BDCs, we examined their uptake of FITC-dextran over time from day 0 to day 7. The ability to take up FITC-dextran increased from 29 ± 30% (mean ± SD) on day 1 to 58 ± 24%
on day 4 and 57 ± 27% on day 6. In contrast, 16 ± 18% of BDCs on day 1 were endocytically active following their Epigenetics inhibitor isolation from blood. Laser confocal microscopy confirmed the uptake of particles of FITC-dextran in both MoDCs and BDCs (data not shown). Overall, these results show that BDCs were consistently less endocytic than MoDCs. As DCs mature, the expression of co-stimulatory molecules such as CD80 or CD86 increases providing DCs with the ability to activate T cells. Furthermore, up-regulation of the chemokine receptor CCR7 allows DCs to migrate to the lymph node where they encounter lymphocytes.19 To compare the expression of co-stimulatory molecules and CCR7 within each DC population, MoDCs and BDCs were stimulated with LPS (100 ng/ml) for 24-hr. Flow cytometric analysis showed that CD80/86 expression increased from 46% to 67% (median) in MoDCs (stimulation index = 1·5) (Fig. 2a; P < 0·05), and from 14% to 45% in BDCs (stimulation index = 3·8) (Fig. 2b; P < 0·05) as determined by flow cytometry. Within the 6-hr stimulation with LPS, CCR7 gene expression increased by 3·4-fold (median)
in BDCs and 2·0-fold in MoDCs (Fig. 3). In summary, MK-2206 nmr in response to stimulation with LPS both MoDCs and BDCs demonstrated the characteristics of mature DCs in terms of co-stimulatory molecule cell surface expression and CCR7 gene expression. At sites of injury, DCs release
chemokines that are involved in recruiting innate and adaptive immune cells. The ability of DCs to produce chemokines was examined following a 6-hr stimulation with LPS. Over fourfold up-regulation was observed in CCL-4, CCL-20 and CXCL2 SB-3CT gene expression in both MoDCs and BDCs (Fig. 4a) with the up-regulation observed to be higher in BDCs for all of the genes examined. In BDCs, there was also CCL-2 up-regulation. In lymph nodes, DCs interact with T cells by delivering different types of signals including cytokines. The expression of cytokines in MoDCs and BDCs was compared by qRT-PCR following a 6-hr stimulation with LPS. No changes were observed in IFN-α and IFN-γ, whereas a greater than threefold up-regulation was observed in IL-12 in BDCs and in IL-6, IL-8 and TNF-α in both MoDCs and BDCs (Fig. 4b). No IL-12 was detected in MoDCs. Cytokine secretion was examined by ELISA following a 24-hr stimulation with LPS. Production of IL-6, IL-8, IL-12 and TNF-α was significantly increased in BDCs (Table 3). Expression of IL-6, IL-8 and TNF-α was increased in MoDCs although the change was not statistically significant. Higher baseline values (control) were observed in MoDCs compared with BDCs.