Maturation of morphology, phenotype and functions of murine bone marrow-derived dendritic cells(DCs) induced by polysaccharide Kureha(PSK)

摘要

The aim of this work was to evaluate the influence of protein-bound polysaccharide Kureha (PSK) on murine dendritic cells (DCs). These impacts of PSK on DCs from bone marrow derived DCs (BMDCs) were assessed with inverted phase contrast microscope, conventional scanning electron microscopy (SEM), transmission electron microscopy (TEM) for morphology, fluorescence activated cell sorting (FACS) analysis, cytochemistry assay for key surface molecules, FITC-dextran for phagocytosis, bio-assay and enzyme linked immunosorbent assay (ELISA) for cytokine production. We found that under the influence of PSK, immature DCs changed into mature DCs with decrease of antigens up-taking, simultaneously high expression of key surface molecules of the MHC classll, CD40, CD80, CD86 and CD83 as well as more production of IL-12p70 and tumor necrosis factor a (TNF-alpha). These data indicate that PSK could markedly promote maturation of DCs and this adjuvant-like activity may have potential therapeutic value in vaccine preparation. Polysaccharide Kureha (PSK, krestin) is a new type of biological response modifier (BRM), extracted from the deep-layer cultivated mycelia of CM-101 stains of Coriolus versicolor (called Yun Zhi in China). Coriolus versicolor is a mushroom which grows on tree trunks and belongs to more-advanced Basidomycetes class of fungi. Nowadays, its therapeutic potentials have been gaining acceptance among patients worldwide. This leads to the discovery of PSK. PSK was prepared in this study with average molecular weight of approximately 100,000, composed of glucans with beta-1, 4 bonds in the main chain and beta-1, 3 or beta-1, 6 bonds in the side chain, binding to the protein through O- or N-glycosidic bond. The polypeptide portion is relatively rich in aspartic, glutamic, and other acidic amino acids. Conventional toxicological assessments indicate PSK is non-toxic andits oral LD50 is low and no abnormalities have been observed in subacute and chronic toxicity tests. Previous studies in vitro had reported that PSK could directly inhibit the proliferation of leukemia, lymphoma, hepatoma, breast and lung tumor cell lines in a dose-dependent manner. Dendritic cells (DCs), the potent antigen cells (APCs), play an important role in the initial immune response against foreign antigens and are known to be activated by recognizing various foreign pathogens via the Toll-like receptors (TLRs), but are also very involved in tumor immunity and tumor elimination by the immune system.8 DCs form a system composed of distinct subsets that differ in their expression of endocytic and signaling receptors.