Armillariella mellea induces maturation of human dendritic cells without induction of cytokine expression.

ETHNOPHARMACOLOGICAL RELEVANCE: Armillariella mellea, an edible and medicinal mushroom possessing immuno-modulating potential, has been frequently used for the treatment of infectious diseases or cancers. AIM OF THE STUDY: In order to elucidate immune-regulatory mechanisms of Armillariella mellea, we investigated the effect of water-soluble components from Armillariella mellea (AME) on the regulation of human dendritic cell (DC) maturation and activation. MATERIALS AND METHODS: Immature DCs (iDCs) were prepared by differentiating human peripheral blood CD14-positive cells with GM-CSF and IL-4. Then, iDCs were treated with AME at 2-20 microg/ml for 48 h and subjected to flow cytometry to analyze the expression of DC markers. Dextran-FITC uptake assay and enzyme-linked immunosorbent assay were performed to examine the endocytic capacity of AME-stimulated DC and their production of cytokines, respectively. RESULTS: iDCs stimulated with AME showed representative features during DC maturation such as up-regulated expression of CD80, CD83, CD86, both MHC class I and II molecules, and CD205, with a simultaneous decrease in the expression of CD206 and the endocytic capacity. Interestingly, AME was not able to induce the production of TNF-alpha, IL-12p40, or IL-10, whereas lipopolysaccharides induced a substantial increase of all of the cytokines. CONCLUSION: Armillariella mellea induces maturation of human DCs through a unique mechanism without inducing cytokine expression.