Arrest of human dendritic cells at the CD34−/CD4+/HLA-DR+ stage in the bone marrow of NOD/SCID-human chimeric mice

Abstract
Human dendritic cell (DC) precursors were engrafted and maintained in NOD/SCID- human chimeric mice (NOD/SCID-hu mice) implanted with human cord blood mononuclear cells, although no mature human DCs were detected in lymphoid organs of the mice. Two months after implantation, bone marrow (BM) cells of NOD/SCID-hu mice formed colonies showing DC morphology and expressing CD1a in methylcellulose culture with granulocyte-macrophage colony-stimulating factor (GM-CSF) and tumor necrosis factor α (TNF-α). The CD34−/CD4+/HLA-DR+ cell fraction in NOD/SCID-hu mouse BM generated CD1a+ cells that were highly stimulatory in mixed leukocyte reactions in culture with GM-CSF and TNF-α. These results suggest a strong potential for NOD/SCID-hu BM to generate human DCs, although DC differentiation may be blocked at the CD34−/CD4+/HLA-DR+ stage.