Abstract: The purpose of this study is to investigate the immunomodulatory activities, cytotoxicity and anti-tumor activities of polysaccharide from Amanita caesarea (AC-1) in vitro. In this study,we used cytological techniques to explore the immunomodulatory activities of AC-1 on T cells,B cells and RAW264.7 cells in vitro, the cytotoxicity of AC-1 on mouse fibroblasts (L929) and the antineoplastic activities of AC-1 on mouse gastric cancer cells (MFC) and mouse sarcoma cells (S₁₈₀) in vitro.The results showed that AC-1 could significantly stimulate the proliferation of three kinds of immune cells in vitro, and could enhance the phagocytosis activities of RAW264.7 cells,which indicated that AC-1 played an important role in enhancing immunities of the body.Further studies found that AC-1 mainly enhanced humoral immunity by promoting the secretion of Ig E and Ig G.When the concentration of AC-1 was 5-20 μg/mL,it had no obvious promotion or inhibition on L929 cells,suggesting that AC-1 was non-toxic to normal cells. AC-1 could significantly inhibit the growth of mouse gastric cancer cells (MFC) at the concentration of 10-20 μg/mL,but had a weak inhibitory effect on mouse sarcoma cells (S₁₈₀).This indicated that AC-1 could directly inhibit the growth of tumor cells in vitro, but had different inhibitory effects on different tumor cells. In conclusion, Amanita caesarea polysaccharide (AC-1) has good immunomodulatory activities,non-toxic to normal cells and good anti-tumor activities in vitro, however, it has different inhibitory effects on different cancer cells.

Key words: Amanita caesarea, polysaccharide, immunomodulatory activities, cytotoxicity, antitumor activities