Abstract:The fruiting body of the wild strain E70 suspected as Lepista sordida collected and isolated by the Dazhou Academy of Agricultural Sciences was identified based on morphological and molecular biological evidence.Single factor tests were conducted to study the influences of non-nutritional factors on the production of extracellular polysaccharide by liquid fermentation.The effects of extracellular polysaccharide on the proliferation of B cells，T cells，and RAW 264.7 macrophages were investigated by the cell counting kit-8 method. The wild strain E70 was identified as L.sordida.The optimal non-nutritional factors for the synthesis of extracellular polysaccharide were inoculation amount of 20 PC（0.1 cm2/PC），temperature of 25 ℃，and rotation speed of 180 r/min. Under these conditions，the extracellular polysaccharide yield was as high as（6.07±0.26）g/L. The extracellular polysaccharide of L.sordida E70 at different concentrations had significant proliferative effects on the proliferation of B cells，T cells，and macrophages in mice.Particularly，it exerted the strongest promoting effect on the proliferation of B cells，which showed the highest proliferation rate of 65.89% at the extracellular polysaccharide concentration of 40 μg/mL（P＜0.000 1）.