The ontogeny of dendritic cells. This figure summarizes the pathways leading to dendritic cell (DC) development in the bone marrow and peripheral tissue. Differentiation of DCs is dependent on multiple cytokines and transcription factors. HSC, hematopoietic stem cell; CMP, common myeloid progenitor; MDP, macrophage–DC progenitor; CDP, common DC progenitor; CLP, common lymphoid progenitor; pre-cDC, classical/conventional DC progenitor; cDC1, type 1 classical/conventional DC; cDC2, type 2 classical/conventional DC; pDC, plasmacytoid DC; MoDC, monocyte-derived DC; FLT3L, FMS-like tyrosine kinase 3 ligand; CSF-1, colony-stimulating factor 1; IRF, interferon-regulatory factor; STAT3, signal transducer and activator of transcription 3; IL, interleukin.