Immunomodulatory agents used as complementary or alternative medicines have become popular for treating different immune disorders. Especially, co-administration of immunomodulatory agents and anti-tumor drugs is used to reduce the harmful side effect of chemotherapy . Numerous natural substances extracted from plants or animals were found to be beneficial to ameliorate disease symptoms by stimulating both innate and adaptive immunity. Among these, the bioactive polysaccharides isolated from natural source have recently been studied as a new immunopotentiator source for their profound effect on the immune system with relative nontoxicity and no significant side effects . They exert a variety of immune regulatory functions including the activation of immune-related cells, promotion of cytokine or chemokine secretion as well as activation of complement system . Until now, various polysaccharides have been applied as immunomodulators in clinic, such as lentinan (LNT) , krestin (PSK) , Astragalus polysaccharides (APS)  and Panax ginseng polysaccharides (GPS) .