Soluble β-glucan from Grifola frondosa induces proliferation and Dectin-1/Syk signaling in resident macrophages via the GM-CSF autocrine pathway.

MD-Fraction, a highly purified, soluble β-(1,3) (1,6)-glucan obtained from Grifola frondosa (an oriental edible mushroom), has been reported to inhibit tumor growth by modulating host immunity. β-Glucan, a major component of the fungal cell wall, is generally recognized by PRRs expressed on macrophages and DCs, such as Dectin-1, and the ability of β-glucans to modulate host immunity is influenced by their structure and purity. Most cellular studies have used particulate β-glucans, such as yeast zymosan (crude β-glucan) and curdlan (purified β-glucan).