Abstract: Objective Study the effect of Sca1+ cells on the HSCs`(hemopoietic stem cells) differentiation to dendritic cells （DCs）, and identify the morphology, function and surface markers of the cells. Methods CD117＋ HSCs were isolated and purified from the bone marrow of healthy Balb/c mice by magnetic affinity cell sorting. After cell expansion by treatment with the support of Sca1+ cells, the HSCs were induced for directional differentiation into DC-like cells.Studied the surface markers by FACS and function via LSCM and animal experiments. Results After 10 days of culture , we demonstrated that Sca1+ cells induced HSCs to differentiate into a distinct regulatory DC subset with high expression of CD11b but low expression of Ia. They had phagocytotic activity,and can suppressed the GVHD（graft versus host disease） reaction. Conclusion HSCs can differented to dendritic cells with the support of Sca1+ cells.

Key words: hematopoietic stem cell, dendritic cell, directional differitiation, Sca1+