1 Convergent Differentiation: Myeloid and lymphoid pathways to murine

2 The developmental origin of interferon-producing plasmacytoid dendritic cells (pDC) has been uncertain. We tracked the development of pDC in cultures of bone marrow precursors stimulated with Flt3 ligand. Common myeloid precursors (CMP) produced both conventional DC (cDC) and pDC, via the DC-restricted common DC precursor (CDP). Common lymphoid precursors (CLP) produced only a few cDC with variable efficiency, but produced pDC via a transient intermediate precursor with B cell potential. The pDC of both origins produced interferon-α when stimulated with CpG oligonucleotides. The pDC of CLP origin showed evidence of past RAG1 expression and had D-J rearrangements in IgH genes. Most pDC and all cDC of CMP origin lacked these signs of a lymphoid past. However in these cultures a proportion of pDC of CMP origin showed evidence of past RAG1 expression and had D-J IgH gene rearrangements; most of these derived from a subset of CMP already expressing RAG1. For personal use only.on May 8, 2016. by guest www.bloodjournal.orgFro