Ex vivo generation of functional dendritic cells from mobilized CD34+ hematopoietic stem cells

The ability to generate dendritic cells (DCs) in sizeable numbers has enormous implications for the development of clinically-effective antigen presentation procedures for cancer immunotherapy. We evaluated the generation of immunostimulatory DCs from peripheral blood cells collected from healthy donors. cells purified from leukapheresis product were seeded at in complete medium supplemented with GM-CSF, TNF alpha, IL-4, c-kit ligand, and flt3 ligand (FL). By day 14 of culture in the presence of GM-CSF + TNF alpha, the total cell number increased by compared to the starting number of cells. When the c-kit and FL were added to GM-CSF and TNF alpha, the cell number increased by without affecting the immunophenotype of recovered cells. Flow cytometric analysis indicated that cells with the markers of mature dendritic cells, i.e., , and +, constituted , and , respectively. This pattern of expression of surface antigen was unchanged whether the c-kit ligand and/or FL was added. The irradiated cells recovered from in vitro cultures elicit a vigorous proliferation of allogeneic peripheral blood T-cells, irrespective of cytokine combinations. These findings provide advantageous tools for the large-scale generation of DCs that are potentially usable for clinical protocols of immunotherapy or vaccination in patients undergoing cancer treatment.