Efficient ex vivo generation of dendritic cells from CD14(+) blood monocytes in the presence of human serum albumin for use in clinical vaccine trials

Dendritic cells (DC) with the potential to induce anti-tumour immunity repr esent one of the promising candidates for cancer vaccines. Efficiency of ex vivo DC generation depends on culture conditions, especially protein compo nents in the plasma or serum used. Using human serum albumin (HSA), we devi sed a constant and reproducible culture method for DC generation from perip heral blood CD14(+) cells. The number of DC obtained with 2% HSA-supplement ed cultures containing granulocyte-macrophage colony-stimulating factor and interleukin 4 were consistently higher than in cultures with various conce ntrations of autologous plasma or serum. The concentrations and time points tested for plasma or serum considerably affected the number of DC recovere d. DC prepared with HSA acquired the ability to uptake dextran, and express ed high levels of major histocompatibility (MHC) and co-stimulatory molecul es similar to DC cultured with autologous plasma or serum. Although DC cult ured with autologous plasma or serum consisted of CD1a(+) and CD1a(-) popul ations, DC differentiated in the presence of HSA expressed CD1a. DC obtaine d with HSA primed and induced immunogenic peptide-specific cytotoxic T lymp hocytes against a tumour rejection antigen, HER2. These findings suggest th at our method for preparation of DC with HSA should prove valuable in DC ge neration for immunotherapy.