Regulation on maturation and function of dendritic cells by Astragalus mongholicus polysaccharides

Astragalus mongholicus polysaccharides(ASP) isolated from one of the Chinese herbs—A. mongholicus which are known to have a variety of immunomodulatory activity. However, little is known about their immunomodulatory effects on murine bone marrow (BM)-derived dendritic cells (DC). DC are professional antigen presenting cells, which are pivotal for initiation of primary immune response. In this study, the regulatory effects of ASP on maturation and function of cultured murine BM-derived DC were investigated in vitro. ASP (10, 50, 100, 250 μg/ml) could increase the co-expression of CD-11c and MHC class II molecules on DC surface, and the 100 μg/ml is the optimal dose. The ability of unstimulated DC to uptake FITC-dextran was higher than that of ASP- or LPS-treated DC. We analyzed the concentration of IL-12 secreted by DC using ELISA. ASP-treated DC secreted a higher level of IL-12 than untreated DC. And ASP- or LPS-treated DC displayed a more mature morphology, with long protrusions, while untreated-DC displayed shorter protrusions than stimulated DC.