Dendritic Cell Generation from Highly Purified CD14+Monocytes

Dendritic cells (DC) play a pivotal role in the function of the immune system, for they are the primary antigen-presenting cells (APC) in the activation of naive T-lymphocyte responses (1 ). Recent studies have uncovered complexity in the DC lineage with several subsets, functions, and maturational stages. Although it is generally accepted that human DC derive from hematopoietic progenitor cells (2 -9 ), it is not clear at present whether DC cells and their precursors represent a separate hematopoietic lineage or whether DC should be seen as specialized macrophages with particular morphological, molecular, and functional features. Several lines of evidence point to DC and monocytes/ macrophages being offspring of the same CD34⁺ hematopoietic progenitor cell (3 -5 ,12 -14 , and reviewed in ([10 ,11 ].) DC committed precursor cells have also been identified in peripheral blood (15 -18 ).