Cells responsible for restoration of haemopoiesis in long-term murine bone marrow culture.

Long-term haemopoiesis in bone marrow culture is sustained by the progeny of haemopoietic progenitor cells (HPC), which differ from CFUs by very low sensitivity to repeated hydroxyurea (HU) injections. The transit time of a haemopoietic clone from HPC to cells proliferating in culture is 6-7 weeks. The results suggest that the stem cell continuum is an expansion type compartment, members of which gradually lose their proliferative potential during differentiation.