Abstract: BACKGROUND ＆ AIM: To study the anti_tumor effects, efficacy enhancement and immunoregulatory function of intracellular polysaccharide(IPS) from liquid state fermentation of Phellinus linteus in S180_bearing mouse and provide evidence for exploring IPS. MATERIALS AND METHODS: S180_bearing mice were divided into 9 groups (10 mice per group) which were normal group, tumour_bearing group, Cyclophosphamide(CP) group, IPS (50, 100, 200 mg/kg) groups and co_administration groups of IPS(50,100,200 mg/kg) with CP. The anti_tumor effects and the influences on immunity function of both IPS and co_administration of IPS with CP were observed. The MTT method was used to measure the proliferation activity of splenic lymphocytes of S180_bearing mouse. RESULTS: At doses of 200 and 100 mg/kg, inhibition rates of S180 sarcoma were 57.02％ and 61.40％ respectively. The inhibition rate of co_administration of 100 mg/kg IPS with CP could reach 79.51％. IPS significantly increased thymus index and spleen index of S180_bearing mouse and protect the immune organs aginst CP. IPS promoted the growth of leucocytes and inhibited its reduction induced by CP. Besides, IPS enhanced cell_mediated immunity by accelerating T_cell proliferation. CONCLUSION: IPS of Phellinus linteus was shown to have significant anti_tumor effects and promoted the immune function of tumor_bearing mice. IPS could also mitigate the toxic and side effects of chemotherapeutic agents and enhancing the efficacy of CP.

Key words: phellinus linteus, intracellular polysaccharide, S180, anti_tumor, immunity