5.

Optimization of DC maturation. Left-hand panels: Expression density (MFI) of the indicated DC membrane molecules and viability of mDCs as well as IL-12 secretion during the differentiation of smDCs into mDCs is shown after exposure to increasing concentrations of lipopolysaccharide (LPS) at constant IFN-γ concentration. Data from two healthy donors are shown. Right-hand panel: LPS at a concentration of 30 ng/ml was applied for 6 hrs (+) or the DCs were left immature (–) in the presence of IFN-β. According to the DC-manufacturing protocol for cancer vaccines, DC cultures were frozen after 6 hrs in liquid nitrogen, recovered from freezing and re-cultured; or DCs were continuously cultured until hour = 48 as indicated. * Below the detection limit of the IL-12 ELISA.