Description

Natural killer (NK) cells play a key role in the innate immune system. These effector lymphocytes react to certain infections and malignancies by directly destroying infected or transformed cells and by secretion of potent immune system cytokines that stimulate and guide other white blood cells to the target area. NK cells have the ability to recognize foreign or stressed cells that lack antibodies or major histocompatibility complex (MHC) class I proteins on the surface. If not restrained by inhibitory receptors recognizing MHC class I proteins on the surface of self-cells, NK cells are able to kill normal, healthy cells.