Effect of a glucan, sizofiran, on natural-killer activity of 5-fluorouracil-treated murine bone marrow cells.

The number of bone marrow cells in C3H/He mice was reduced 3-4 days after treatment with 130 mg/kg intraperitoneal 5-fluorouracil (5-FU). Higher rates of spontaneous proliferation and natural killer (NK) activity, accompanied by an increase in asialoGM1-positive cells, were observed in treated mice. When sizofiran at a dose of 200 micrograms/animal was intramuscularly injected after 5-FU treatment, the rates of proliferation and NK activity of bone marrow cells were higher than with 5-FU alone. The cell number was not influenced by sizofiran alone. These results indicate that all precursors of the various mature cell types (including NK cells) differentiate and regenerate rapidly to replace cells damaged by 5-FU treatment, and that sizofiran has the potential to assist this recovery. These results suggest that administration of sizofiran after chemotherapy may be useful in cancer patients.