Stem cells with short-term and long-term repopulating ability in the mouse.

In the adult mouse the bone marrow serves as the major site for blood cell production and development. The large majority of the cells present in the bone marrow are relatively mature and derived from a small proportion designated as hematopoietic stem cells. These cells are capable of developing into all mature blood cell types and have the capacity of serf renewal. Hematopoietic stem cells represent approximately 0.05% of cells in the bone marrow, but they are thought to be responsible for short-term and long-term repopulation of hematopoietic tissues in the host following lethal irradiation and transplantation. Over the past years, methods have been developed to purify and identify hematopoietic stem cells, allowing functional characterization in in vitro and in vivo assays.