A Novel Exopolysaccharide from the Biofilm of Thermus aquaticus YT-1 Induces the Immune Response through Toll-like Receptor 2

Bacterial polysaccharides are known to induce the immune response in macrophages. Here we isolated a novel extracellular polysaccharide from the biofilm of Thermus aquaticus YT-1 and evaluated its structure and immunomodulatory effects. The size of this polysaccharide, TA-1, was deduced by size-exclusion chromatography as 500 kDa. GC-MS, high performance anionexchange chromatography with pulsed amperometric detection, electrospray ionization-MS/MS, and NMR revealed the novel structure of TA-1. The polysaccharide is composed of tetrasaccharide- repeating units of galactofuranose, galactopyranose, and N-acetylgalactosamine (1:1:2) and lacked acidic sugars. TA-1 stimulated macrophage cells to produce the cytokines TNF-α and IL-6. Screening of Toll-like receptors and antibody blocking experiments indicated that the natural receptor of TA-1 in its immunoactivity is TLR2. Recognition of TA-1 by TLR2 was confirmed by TA-1 induction of IL-6 production in peritoneal macrophages from wild-type mice but not from TLR2_/_ mice. TA-1, as a TLR2 agonist, could possibly be used as an adjuvant and could enhance cytokine release, which increases the immune response. Furthermore, TA-1 induced cytokine release is dependent on MyD88/TIRAP.
Yu-Liang Yang

Lin M-H, Yang Y-L, Chen Y-P, Hua K-F, Lu C-P, Sheu F, Lin G-H, Tsay S-S, Liang S-M, Wu S-H (2011) A Novel Exopolysaccharide from the Biofilm of Thermus aquaticus YT-1 Induces the Immune Response through Toll-like Receptor 2 Journal of Biological Chemistry, 286(20):17736-45