Studies on molecular mechanisms of natural killer cell functionality in human and rat.1: Protease production

Two types of proteases with molecular weight between 97 and 66 kD were detected in condition media from mixed culture of human or rat natural killer with tumor cells. Meanwhile, human natural killer cells alone showed only 1 protease. Whereas the rat natural killer cells still had the 2 types of the proteases with weaker activity. The protease secreted by the previous natural killer cells were in latent form and required trypsin enzyme to be active. The work suggested the secretion of proteases by natural killer cells as one of the possible biological mechanisms involved in their mode of functions