Glucan-induced hemopoietic and immune stimulation: therapeutic effects in sublethally and lethally irradiated mice.

The hemopoietic effects of glucan, a beta 1,3 polyglycan biological response modifier, were assayed in normal and irradiated mice. In normal mice, glucan administration increased the content of bone marrow and splenic transplantable pluripotent hemopoietic stem cells (CFU-s), committed granulocyte-macrophage progenitor cells (GM-CFC), and pure macrophage progenitor cells (M-CFC). In mice partially hemopoietic depleted by exposure to 6.5 Gy of 60Co irradiation glucan increased the number of endogenous pluripotent hemopoietic stem cells (E-CFU). The most pronounced effects were observed when glucan was administered 1 day before irradiation. In addition, the administration of glucan 1 day before lethal (9.0 Gy) irradiation-enhanced survival. The enhanced survival in glucan-treated mice in part appeared to be mediated by an enhanced resistance to the surgence of enteric opportunistic pathogens that occurs following radiation-induced hemopoietic and immune depression.