Figure 1: IDO-silenced DC vaccine. (a) Schematic illustration of the vaccine design. (b) IDO gene silencing in the DC vaccine. Fast DC preparations were transfected with IDO siRNA under GMP conditions, as described previously [14]. At 24 h after transfection, IDO expression was investigated by western blots, and the remaining cells were cryopreserved into vaccine doses and stored in a GMP-dedicated area. Lanes 1 and 2 correspond to DCs transfected with IDO siRNA and mRNA encoding for hTERT and DCs transfected with IDO siRNA and mRNA encoding for survivin, respectively. Mock DCs were not transfected with IDO siRNA. (c) Potency of IDO-silenced DC in stimulating allogeneic T-cells. Patient IDO-silenced DCs and IDO-positive DC vaccine preparations were cocultured with CD4+ T-cells from a healthy donor at a T-cell DC ratio of 1 : 5. After 5 days in culture, T-cell proliferation was determined by incorporation of [3H]-thymidine following overnight pulsing. The results are presented as the mean ± standard deviation of triplicate determinations. and . IDO: indoleamine 2,3-dioxygenase; siRNA: small interfering RNA; DC: dendritic cells.