Natural Killer Cells (NK cells) constitute a small fraction (5-10%) of human peripheral blood and serve as the first line of defense in innate immunity. Their defining characteristic is the ability to directly recognize, lyse, and destroy tumor cells and virus-infected cells without prior sensitization. They exert their cytolytic effect by secreting perforin, serine proteases such as granzyme A and B, sulfated chondroitin sulfate proteoglycans to degrade cell membranes and disrupt target cell integrity, thereby exerting a cytolytic effect. They exhibit potent killing activity against tumor cells that do not express MHC molecules. This product is suitable for rapid in vitro expansion of NK cells. Components are clearly defined with no heterologous elements; High expansion efficiency, achieving over 500-fold NK cell proliferation; Final NK cell purity reaches over 95%.