EFFECT OF RECOMBINANT HUMAN GRANULOCYTE-COLONY-STIMULATING FACTOR TREATMENT OF MICE ON SPLEEN COLONY-FORMING UNIT NUMBER AND SELF-RENEWAL CAPACITY

The aim of this investigation was to find out whether the self-renewal capacity of spleen colony-forming units (CFU-S) changed after treatme nt of CBF1 (CBA-LacxC57B1/6) F1 female mice with granulocyte colony-st imulating factor (G-CSF). In addition, the possibility of synergism be tween erythropoietin (Epo) and G-CSF in blood stem cell mobilization w as studied. Twenty-five and 250 mu g/kg/d injections of recombinant hu man (rh) G-CSF expanded the number of CFU-S in peripheral blood four- and 32-fold. The self-maintenance potential of CFU-S did not change si gnificantly. The treatment of mice with 250 mu g/kg/d rhG-CSF resulted in a two-fold increase of spleen cellularity and a 15-fold augmentati on of CFU-S number, without noticeable changes in their self-renewal c apacity. Moderate changes in CFU-S number were observed after Epo admi nistration in spleen and peripheral blood; however, no significant syn ergistic effect of Epo was detected with either dose of rhG-CSF. The m ultifold increase of CFU-S number in peripheral blood following rhG-CS F administration, with no reduction in their generating potential, sug gests that rhG-CSF-mobilized blood stem cells provide an appropriate s ource for reconstitution of the hematopoietic system.