Dendritic Cell Development from Mobilized Peripheral Blood CD34+Cells

Dendritic cells are not a homogenous population, but develop through different differentiation pathways, whose prominence is dependent on the cytokine milieu. Although dendritic cells can be readily derived from monocytes, dendritic cells that develop from CD34⁺ progenitor cells have a more efficient antigen-presenting capability (1 ). However, even the development of dendritic cells from CD34⁺ progenitor cells can occur through several different pathways (2 ,3 ). In one differentiation pathway, CD34⁺ cells mature into committed CD14-CD1a⁺ precursor cells that give rise to CD1a⁺ dendritic cells. In a second differentiation pathway, CD34⁺ cells first develop into bipotential CD14⁺ CDla precursor cells, which mature into bipotential CD14⁺ CD1a⁺ intermediate precursor cells. These intermediate cells can differentiate into monocytic cells in the presence of colony stimulating factor 1 (CSF-1), or into dendritic cells in the absence of CSF-1 (3 ,4 ).