Dendritic cells (DCs) are the primary professional antigen presenting cells of the immune system. They have a central function for the initiation, programming and regulation of antigen-specific immune responses. In vitro, human DCs are often generated from peripheral blood monocytes using GM-CSF and IL-4. These monocyte-derived DCs (Mo-DCs) have the characteristics of immature DCs. Mature Mo-DCs can be obtained by culturing Mo-DCs in the presence of microbial, pro-inflammatory, or T cell-derived stimuli. Mo-DCs have been tested in a broad range of immunotherapy-based protocols, primarily for cancer research.