Development of a serum-free induction medium for the induction of human CD40+CD209+ dendritic cells from CD14+ monocytes

• A serum-free dendritic cell (SF-DC) induction medium was proposed. • The induced DCs expressed correct surface markers and exhibited endocytosis ability. • The induced DCs secreted obvious amounts of cytokines. • The induced DCs showed an excellent ability to stimulate T cell proliferation. • SF-DC induction medium can provide a promising DC source for cell immunotherapy. Dendritic cells (DCs) are a promising cell type for cell immunotherapy due to their unique functions. The generation of monocyte-derived DCs for clinical immunotherapy requires the use of well-defined components and culture conditions to follow clinical regulations. Therefore, the aim of this study was to develop a serum-free medium for the induction of monocyte-derived DCs. In this study, monocytes were isolated from cord blood. First, three different concentration compositions of cytokines (GM-CSF and IL-4) were tested. Then, effective serum substitutes were selected to optimize the compositions. Herein, a serum-free DC (SF-DC) induction medium was proposed to further induce large numbers of functional DCs from monocytes. After culturing, the characteristics and functions of induced DCs were confirmed by surface markers, morphology, TNF-α-stimulated maturation, mixed lymphocyte reaction, endocytosis ability and cytokine secretion. The results showed that the serum-free induced DCs expressed DC-related surface markers and exhibited endocytosis ability. Importantly, the serum-free induced DCs secreted higher amounts of IL-1β, IL-6, IL-12p70 and TNF and showed a better ability to stimulate T cell proliferation than those in serum-containing medium. Taken together, SF-DC induction medium was successfully developed and can provide a promising source of DCs for future cell immunotherapy.