An injectable formulation of the polysaccharide beta 1,3/1,6 glucan derived from the cell wall of the yeast Saccharomyces cerevisiae with potential immunomodulating and antineoplastic activities. PGG beta-glucan binds to an alternate site on the neutrophil complement receptor 3 (CR3), priming the neurophil to become cytotoxic when binding to complement on tumor cells via CR3. This agent has been reported to selectively activate immune cells without inducing pro-inflammatory cytokines, potentially reducing potential side effects observed with the induction of broad innate immune repsonses. In addition, PGG beta-glucan may induce hematopoietic progenitor cell (HPC) mobilization.