Effect of glucan, a macrophage activator, on murine hemopoietic cell proliferation in diffusion chambers in mice.

Pretreatment of mice with glucan, a potent macrophage activator, resulted in enhanced myeloid cluster and colony formation by bone marrow cells in diffusion chambers implanted into the peritoneal cavity. Simultaneously, erythroid colony formation was also augmented. In some experiments the plasma clots formed inside the chambers were dissolved, and the number of hematopoietic cells was determined. An increased yield of early proliferative cells, granulocytes, and macrophages was found in glucan-treated hosts. Concomitantly, higher leukocyte counts were noted in the peripheral blood of treated animals. These results suggest that glucan has a strong stimulatory effect on hematopoiesis. This stimulation is probably mediated by humoral factors of host animal origin rather than by direct interaction with proliferating hematopoietic precursors enclosed within the chambers.