Abstract: Provided here, amongst other things, are populations of expanded and stimulated natural killer cells, pharmaceutical compositions comprising populations of expanded and stimulated natural killer cells, and methods of expanding and stimulating natural killer cells

Abstract: The present disclosure relates to a method for producing natural killer (NK) cells. More specifically, the present disclosure relates to a method for producing NK cells, characterized in that peripheral blood mononuclear cells from which CD3-positive cells are removed are proliferated together with feeder cells, and the peripheral blood mononuclear cells are re-stimulated with feeder cells at the time of reaching a specific accumulated population doubling level. The present disclosure also relates to a method for producing NK cells, characterized in that NK cells are cultured under appropriate culture conditions by using a bioreactor. The production method according to the present disclosure has an advantage that NK cells having a high cell-killing ability and cell survival rate can be produced with high purity and at high efficiency in a short period of time by a clinically friendly method as compared with existing methods, thereby increasing the productivity of an NK cell therapy agent.