Natural Killer Cell Mediated Defence Directed Selectively Against Target Cells Lacking MHC Class I Gene Products

Natural killer (NK) cells represent an important subset of lymphocytes. These cells fulfil crucial cytotoxic as well as regulatory functions of the immune system. Compromised NK cell activity has been found to be associated with the development of several diseases, including cancer, AIDS and virus infections. Intact NK cell activity appears to play an important role in health. More recent data suggests that NK cells may be involved in the pathogenisis of some human diseases and serve as an early predictor for susceptibility to disease [1]. In transplantation, NK cells participate in rejection of allogeneic bone marrow cells [2].