Abstract: Mixed lymphocyte response was used as a main model through all theexperiments In a series of concentrations (25, 50, 100, and 200μg/mi ), Ganoderma polysaccharides(GL- B) promoted the production of interleukin 2(IL- 2) in a concentra-tion- dependent manner after initiation of culture for 12 h and increased the total cell recoveryas well as that of Lyt 2⁺ and L3T4⁺ cells after 4 days of culture. The data also show thatthe polysaccharides markedly enhanced the cytotoxicity of cytotoxic T lymphocytes, which wasincreased by 100% at the concentration of 200 μg/ml.