Mouse CD11c+ B220+ Gr1+plasmacytoid dendritic cells develop independently of the T-cell lineage

Abstract

The developmental origin of dendritic cells (DCs) is controversial. In the mouse CD8α⁺ and CD8α⁻ DC subsets are often considered to be of lymphoid and myeloid origin respectively, although evidence on this point is conflicting. Very recently a novel CD11c⁺ B220⁺ DC subset has been identified that appears to be the murine counterpart to interferon alpha (IFNα)–producing human plasmacytoid DCs (PDCs). We show here that CD11c⁺ B220⁺ mouse PDCs, like human PDCs, are present in the thymus and express T lineage markers such as CD8α and CD4. However, the intrathymic development of PDCs can be completely dissociated from immature T lineage cells in mixed chimeras established with bone marrow cells from mice deficient for either Notch-1 or T-cell factor 1, two independent mutations that severely block early T-cell development. Our data indicate that thymic PDCs do not arise from a bipotential T/DC precursor.