Dose-dependent responses of murine pluripotent stem cells and myeloid and erythroid progenitor cells following administration of the immunomodulating agent glucan.

The hemopoietic effects produced by six different doses of a commercially available glucan preparation were investigated. C3H/HeN mice were intravenously injected with either 0.1, 0.4, 0.8, 1.2, 1.6, or 2.0 mg of glucan. Five days later, total nucleated cellularity, pluripotent stem cells (CFU-s), granulocyte-macrophage colony-forming cells (GM-CFC), macrophage colony-forming cells (M-CFC), and erythroid burst- and colony-forming cells (BFU-e and CFU-e) were assayed in the bone marrow and spleen. Neither femoral cellularity nor GM-CFC content was altered by any of the glucan doses tested. By contrast, bone marrow CFU-s content increased and CFU-e and BFU-e contents decreased with increasing glucan doses. In the spleen, all aspects of hemopoiesis (i.e., cellularity, CFU-s, GM-CFC, M-CFC, and CFU-e) increased after glucan administration. The degree of splenic enhancement was directly correlated with the dose of glucan administered.