However, a few studies have reported that artificially programmed DCs exhibited remarkable changes in phenotype. Immature DCs pre-treated with dexamethasone and subsequently stimulated with tumor necrosis factor-α (TNF-α) exhibited an endocytic

capacity four times higher (at maximum dexamethasone concentration) than iDCs treated with only TNF-α.[34] Clingan et al.,[35] reported that pre-treatment of iDCs with either interleukin-4 (IL-4) or interferon-γ (IFN-γ) inhibited the migration of iDCs in response to CCL3. Coincidentally, they observed that when IL-4 or IFN-γ pre-treated DCs were incubated with FITC-dextran in the presence of CCL3 for 2 min, dextran uptake capacity of the DCs was significantly enhanced by approximately fourfold (IFN-γ) or fivefold (IL-4) versus Y-27632 research buy without CCL3. Yanagawa and Onoe,[36] found that CCL3 and CCL19 rapidly (in less than an hour) Antiinfection Compound Library purchase and selectively enhanced the internalization ability of iDCs and mDCs, respectively, when dextran and chemokines were added simultaneously to

the cell culture. They also noted that CCL19 induced an actin-reorganization related to the endocytic behaviour of mDCs.[37] Moreover, the synergistic effects of combinations of cytokines have been shown on the expansion of blood progenitors,[38] on the endocytic pathway in insulin-producing cells,[39] and on the migration and development of other phenotypes in endothelial cells.[40] Hence it may be possible, using selected chemokines or their combinations, to artificially program iDCs, thereby controlling their phenotypes and maturation status in order to enhance antigen uptake and presentation. We report here the first study to engineer DC phenotypes with select chemokine application to enhance antigen uptake and processing capacity of DCs, which can directly affect antigen presentation and DC-based vaccine efficiency in future. Dendritic cells were pre-treated with PtdIns(3,4)P2 the individual chemokines CCL3, CCL19, or their combination in various ratios. Then, 24 hr later, DCs were exposed to lipopolysaccharide (LPS), [a Toll-like receptor 4 (TLR4) ligand], to induce maturation. We demonstrate that when DCs are pre-treated with a chemokine combination of CCL3 : CCL19

in a specific ratio then subsequently stimulated with LPS, certain phenotypic changes arise that are significantly different from those of iDCs or DCs stimulated only with LPS. Dendritic cells programmed with a specific chemokine combination (CCL3 : CCL19 = 7 : 3) retained antigen uptake capacity and exhibited antigen-processing capacity, even after subsequent LPS maturation stimulus, at levels higher than iDCs (36%), and iDCs treated only with LPS (27%), respectively. Along with antigen uptake, this chemokine programming of DCs also modulated expression of MHC molecules and various cytokine responses of DCs even after maturation of DCs. Results here suggest chemokine programming may be a new tool for enhancing ex vivo and in vivo immunotherapy vaccine strategies.