Self-renewal capacity of mobilized murine haemopoietic stem cells

Self-renewal capacity of stem cells (9 day CFU-S) circulating in the blood and that of CFU-S mobilized into the circulation by various agents was compared in BDF1 mice. For CFU-S mobilization 1.5 mg trypsin, 150 micrograms endotoxin, 1 mg Zymosan per mouse or 5 mg/kg methylprednisolone were injected i.v. and the blood CFU-S level was measured 15 min to several days after provocation. Self-renewal capacity of the mobilized CFU-S showed a 4 to 14-fold increase if compared to that of normal blood CFU-S. This, however, proved to be lower than that of bone marrow CFU-S. This increase in self-renewal capacity was independent of the type of mobilizer, suggesting that CFU-S mobilizing agents, in general, release the same subpopulation of CFU-S. The fairly good correlation between the amount and self-renewal capacity of CFU-S in the circulation supported the assumption that, up to a certain limit, the more CFU-S are mobilized, the better quality stem cells can be obtained for transplantation purposes.