要約

Many plant extracts are used as well-known folk medicines and exhibit various biological activities that are beneficial to human health. These extracts contain polysaccharides, and some are pathogen-associated molecular patterns (PAMPs) that stimulate innate as well as acquired immune systems. In the present study, the cooperative effects of PAMPs and bamboo water-soluble methanol precipitation (BWMP) in a macromolecular fraction of the hot water extract of Sasa veitchii (in Japanese folk medicine, known as Kumazasa; family Poaceae) were analyzed in vitro using the spleen or bone marrow cells of mice. The splenocytes of male DBA/2 and C57BL/6 mice were cultured with BWMP in the presence or absence of PAMPs, and responses were assessed by measuring cytokines. BWMP inhibited the production of interferon gamma (IFN−γ) by not only toll like receptors (TLRs), but also the C-type lectin receptors (CLRs) dectin-1 and dectin-2. BWMP also inhibited the autologous production of IFN−γ in the splenocyte culture. These results suggested that BWMP may inhibit the signaling pathways of PAMPs, but not ligand-receptor interactions. In contrast, BWMP did not inhibit the production of cytokines by dendritic cells. These results indicated that the inhibition of IFN−γ by BWMP was mediated through the cell-to-cell interactions of splenic cells during cultivation.