Immune-enhancing activity of extracellular polysaccharides isolated from Rhizopus nigricans

Extracellular polysaccharides (EPS1-1) was extracted from fermentation liquor of Rhizopus nigricans and evaluated its immune-enhancing activities in vitro and in vivo. Results suggested that the proliferation of lymphocyte was stimulated after treated with EPS1-1. Moreover, the activities of macrophages were enhanced by increasing the activities of phagocytosis and acid phosphatase, the production of NO and the mRNA levels of IL-2, TNF-α and iNOS. Furthermore, EPS1-1 could significantly boost the immunity of normal and immunosuppressed mice, which included the increase of loaded swimming time, footpad swelling, organ index and the secretion of IL-2 and TNF-α in serum, thus suggesting that EPS1-1 could improve the body immunity through cellular immunity and humoral immunity. These findings provided further insights into the potential use of EPS1-1 as immunopotentiator or new function food.