AUGMENTATION OF LYMPHOKINE-ACTIVATED KILLER-CELL ACTIVITY BY LENTINAN

Lymphokine - activated killer (LAK) activity stimulated by interleukin 2 (IL - 2) and/or lentinan was examined in the peripheral blood of 9 healthy subjects and 7 cancer patients. After 4 and 8 days culture, LAK killer activity stimulated by IL - 2 and lentinan against autologous turner and K562 cells was gr eater than that stimulated by IL - 2 alone. The optimal concentration of lentinan for the generation of killer cells ranged from 25 - 500 ng/ml, a level which can be achieved in vivo by the administration of clinical doses of this agent. The expression of CD25 antigen, the a chain of the IL - 2 receptor on the activated killer cells was increased by lentinan. Thus it was shown that LAK cells stimulated with IL - 2 plus lentinan had strong cytotoxicity and might be useful as effector cells for adoptive immunotherapy.