RESUMO

Dendritic cells (DC) are highly specialized antigen-presenting cells (APC) derived from precursors within the bone marrow (BM). They are distributed ubiquitously throughout the body, and are few in number (1). They are classified as lymphoid-related or myeloid DC depending on their developmental lineage. Lymphoid-related DC develop from very immature T-cell precursors or BM progenitors, which are also the source of future natural killer cells and B cells (2,3). In vitro, these lymphoid-derived DC can be generated in the absence of granulocyte macrophage colony stimulating factor (GM-CSF), and are CD8(+) and Fas ligand(+) (CD95L(+)). In the presence of GM-CSF, DC develop directly from myeloid committed precursors, which also give rise to monocytes and granulocytes, or from myelomonocytic cells, which are also precursors of monocytes (4,5). DC can be propagated from progenitors in BM (6), blood (7), or secondary lymphoid tissues (8). In addition, peripheral blood mononuclear cells (PBMC) can develop into DC-like cells if cultured in the presence of GM-CSF and interleukin-4 (IL-4) (9,10).