Changes in WBCs (× 10³; - - - - ) and in the number of clonogenic progenitors (per milliliter of blood) with FL treatment (200 μg/kg/day × 12 days; ▪ for BFU-E, for nonerythroid). Animals A and B were treated with the yeast-derived material and animals C and D with the CHO-derived material. Note the progressive mobilization of progenitors at the end of treatment, especially in animals C and D.