A substantially enriched mammalian
hematopoietic cell subpopulation is provided, which is characterized by
progenitor cell activity for myeloid lineages, but lacking the potential to differentiate into lymphoid lineages. This
population is further divided into specific myeloid
progenitor subsets, including a common myeloid
progenitor cells (CMP),
megakaryocyte / erythroid progenitor cells (MEP) and
granulocyte /
monocyte lineage progenitor (GMP). Methods are provided for the isolation and culture of these subpopulations. The CMP
population gives rise to all myeloid lineages, and can give rise to the two additional and isolatable progenitor populations that are exclusively committed to either the erythroid / megakaryocytic or myelomonocytic lineages. The
cell enrichment methods employ reagents that specifically recognize Thy-1; and IL-7Rα, in conjunction with other markers expressed on lineage committed cells. These cells give rise to a variety of
myeloid cells, including megakaryocytes, granulocytes, dendritic cells and erythroid cells, as evidenced by their growth and differentiation
in vitro and
in vivo.