Efficient Ex Vivo Generation of Human Dendritic Cells from Mobilized CD34^p+ Peripheral Blood Progenitors

Abstract

We tried to efficiently generate human dendritic cells (DCs) from CD34^p+ peripheral blood hematopoietic progenitor cells mobilized by high-dose chemotherapy and subsequent administration of granulocyte colony-stimulating factor, using a liquid suspension culture system. Among various combinations, the combination ofc-kit ligand,flt-3 ligand,c-mpl ligand (TPO), and interleukin (IL)-4 most potently generated the number of CD1a^p+CD14^p- DCs in cultures containing granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor α (TNF-α). The delayed addition of IL-4 on day 6 of culture gave rise to an additional increase in the yield of CD1a^p+CD14^p- DCs that were characterized by the expression of HLA-ABC, HLA-DR, CD80, CD86, and CD83. The majority of the sorted CD1a^p-CD14^p+ cells derived from 6-day culture of CD34^p+cells gave rise to CD1a^p+CD14^p- DCs and CD1a-CD14^p+ macrophages on day 12 of culture in the presence and absence of IL-4, respectively. These findings suggest that IL-4 promotes the differentiation of CD1a^p-CD14^p+ cells derived from mobilized CD34^p+ peripheral blood hematopoietic progenitors to CD1a^p+CD14^p- DCs. The majority of these DCs expressed CD68 but not the Langerhans-associated granule antigen, a finding that suggests they emerge through the monocyte differentiation pathway. The addition of TPO and IL-4 to cultures did not affect the potential of DCs to stimulate the primary allogeneic T-cell response. These findings demonstrated that the combination ofc-kit ligand plusflt-3 ligand plus TPO with GM-CSF plus TNF-α, followed by IL-4, is useful for ex vivo generation of human DCs from mobilized CD34^p+ peripheral blood progenitors.