A clonogenic progenitor with prominent plasmacytoid dendritic cell developmental potential.

Macrophage and dendritic cell (DC) progenitors (MDPs) and common DC progenitors (CDPs) are bone marrow (BM) progenitors with DC differentiation potential. However, both MDPs and CDPs give rise to large numbers of conventional DCs (cDCs) and few plasmacytoid DCs (pDCs), implying that more dedicated pDC progenitors remain to be identified. Here we have described DC progenitors with a prominent pDC differentiation potential. Although both MDPs and CDPs express the macrophage colony stimulating factor (M-CSF) receptor (M-CSFR), the progenitors were confined to a M-CSFR(-) fraction, identified as Lin(-)c-Kit(int/lo)Flt3(+)M-CSFR(-), and expressed high amounts of E2-2 (also known as Tcf4) an essential transcription factor for pDC development. Importantly, they appeared to be directly derived from either CDPs or lymphoid-primed multipotent progenitors (LMPPs). Collectively, our findings provide insight into DC differentiation pathways and may lead to progenitor-based therapeutic applications for infection and autoimmune disease.