Macrophage immunomodulatory activity of a purified polysaccharide isolated from Ganoderma atrum

The objective of this study was to evaluate the immunomodulatory effects of the purified Ganoderma atrum polysaccharide (PSG-1) on murine macrophage cell line RAW264.7. Phagocytotic assay by fluorescein isothiocyanate-dextran internalization showed that PSG-1 stimulated the phagocytosis of macrophages. G. atrum polysaccharide increased the production of NO, and the level of mRNA expression of inducible nitric oxide synthase in a dose-response manner. G. atrum polysaccharide also dose-dependently induced the release of TNF-α and interleukin-1β. Generation of reactive oxygen species was promoted by PSG-1, as determined by flow cytometry. Moreover, PSG-1 induced nuclear factor-κB activation by elevation of p65 nuclear translocation, suggesting that PSG-1 probably stimulated macrophage activities by activating the nuclear factor-κB pathway.