An Immunological Polysaccharide from Tremella fuciformis: Essential Role of Acetylation in Immunomodulation.

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Citation abstract

The edible fungus Tremella fuciformis was shown to have a high molecular weight (1.87 × 10 3 kDa) bioactive polysaccharide, denoted as TFP-F1. Monosaccharide composition and NMR analysis of the polysaccharide and its derivatives indicated it contained fucose (Fuc p ), xylose (Xyl p ), mannose (Man p ), and glucuronic acid (GlcA p ) in a ratio of 0.9:1.0:3.2:1.2. Using IR, NMR, and GC-MS spectroscopic data, the structure of TFP-F1 was elucidated as {→3)-[ β -D-GlcA p -(1→2)]- α -D-Man p -(1→3)- α -D-Man p -(1→3)-[ α -L-Fuc p -(1→2)- β -D-Xyl p -(1→2)]- α -D-Man p -(1→} n, with partial acetylation of C6-OH in mannoses. Furthermore, at a concentration of 1 μg/mL, TFP-F1 was found to stimulate the secretion of TNF-α and IL-6 in J774A.1 macrophage cells in vitro via interaction with toll-like receptor 4 (TLR4). The removal of O -acetyl groups led to the loss of immunomodulatory activities, demonstrating that O -acetyl groups play an essential role in enhancing the production of pro-inflammatory cytokines.