[Natural cellular immunity as the effector mechanism in tumor defense]

According to the immunosurveillance theory, the immune system plays an important role in the control of tumor development. Besides of specific cytotoxic T-cells, natural killer (NK) cells have gained recently in attention as effectors of the aforementioned function. They are lymphoid cells, and lyse tumor cells after having recognized them through a variety of membrane properties. Lymphokines can increase NK cell activity and enlarge their spectrum to previously NK-insensitive targets. Several clinical trials are being conducted at present in order to test the potential of lymphokine activated killer cells to function within this new biologic set-up.