Mulberry leaf polysaccharides modulate murine bone-marrow-derived dendritic cell maturation

Various components of mulberry leaves, such as iminosugars, flavonoids and polysaccharides, have been reported to exert anti-diabetic activity. The purpose of our present study was to examine the modulating effect of mulberry leaf polysaccharides (MLPs) on murine bone-marrow-derived dendritic cells (BMDCs). The ultrastructure, phenotype and functional maturation of BMDCs were studied using transmission electron microscopy (TEM), flow cytometry (FCM), and tested for phagocytosis, acid phosphatase (ACP) activity using an enzyme linked immunosorbent assay (ELISA). Our results demonstrated that MLPs could markedly induce BMDC maturation by up-regulating the expression of membrane phenotypic markers, such as CD80, CD86, CD83,CD40, and MHC II, down-regulating phagocytosis and ACP activity, and by enhancing the production of interleukin 12 (IL-12) and tumor necrosis factor α (TNF-α) secreted by BMDCs. We therefore concluded that MLPs can positively modulate BMDCs.