Characterization and cytokine stimulating activities of heteroglycans from Tremella fuciformis

Three heteroglycans, T1a, T1b, and T1c, have been isolated from the body of Tremella fuciformis Berk. They are composed of mannose (Man), xylose (Xyl), glucose (Glc), fucose (Fuc), and glucuronic acid (GlcA). According to methylation analysis and partial acidic hydrolysis the main chains of T1a, T1b, and T1c consisted of (1-->3)-linked Man, which was branched at the 2, 4, or 6 positions. The branching points were linked with nonreducing terminal GlcA-residues or (1-->6)-linked glucan-chains. Molecular weights of the three heteroglycans are 53,000, 18,000, and 12,000 D respectively, but they undergo self-aggregation in water. T1a-T1c induce human monocytes to produce interleukin-1 (IL-1), interleukin-6 (IL-6), and tumor necrosis factor (TNF) in vitro. Acidic hydrolysate fractions of T1a (T1a-1, 2, 3, 4, 5) with a molecular weight from 53,000 to 1,000 D, also induce human monocytes to produce IL-6 as efficient as T1a.