Dectin-1 mediates the immunoenhancement effect of the polysaccharide from Dictyophora indusiata.

The polysaccharides (DIP) extracted from Dictyophora indusiate has been found featuring great anti-cancer activity through enhancing organism immunity ability, and the DIP-induced macrophages activation might be mediated via TLR4/NF-κB signaling pathway. In this work, we make further investigation of the effect of DIP on macrophages and whether there was another pathway to regulate the immunoenhancement effect of DIP. The results showed that DIP could activate macrophages, causing the enhancement of its phagocyte activity, and then increase the secretion of IL-1β and TNF-α. It could also activate the MAPK pathway and promoted the phosphorylation and nuclear translocation of NF-κB p65. However, these effects of DIP on macrophage was inhibited by anti-Dectin-1, indicating that besides TLR-4, Dectin-1 act as another receptor on macrophage surface which was responsible for the activation effect of DIP. In conclusion, we further illuminate the molecular mechanism involving in the immune enhancement activities on macrophages.