Temporal response of murine pluripotent stem cells and myeloid and erythroid progenitor cells to low-dose glucan treatment.

B6D2F1 female mice were intravenously administered 0.4 mg of glucan. 1, 5, 11, and 17 days later, the total nucleated cellularity (TNC) and the numbers of pluripotent hemopoietic stem cells (CFU-s), granulocyte-macrophage progenitor cells (GM-CFC), and erythroid colony-forming (CFU-e) and burst-forming (BFU-e) cells were assayed in the bone marrow and spleen. Bone marrow TNC was not altered, but splenic TNC increased approximately twofold on day 5 and remained increased on days 11 and 17 after glucan treatment. The concentrations of bone marrow and splenic CFU-s and GM-CFC both significantly increased (p less than 0.01) by 5 days after glucan administration; however, they returned to control levels by day 17. Splenic CFU-e concentration increased on days 5, 11, and 17, whereas splenic BFU-e concentration increased only on day 11 after treatment. By contrast, bone marrow CFU-e and BFU-e concentrations were either unaffected or slightly decreased by glucan treatment. When peripheral blood was assayed for CFU-s and GM-CFC, no detectable increase in the concentrations of these progenitors was noted at any time after glucan treatment. The relevance of these effects of low-dose (0.4 mg) glucan treatment is discussed with respect to previously reported effects of higher-dose (e.g., 4.0 mg) glucan treatment.