Natural Killer Cell

NK cells protect against a variety of cancers and infection. NK cells develop in the bone marrow and constitute about 5-10 % of total lymphocytes in the peripheral circulation and secondary lymphoidal or-gans. Effector functions of NK cells include direct natural cytotoxicity, antibody-dependent cellular cy-totoxicity (ADCC), as well as secretion of inflammatory cytokines and chemokines that indirectly regulate the functions of other immune cells. NK cell development occurs in the bone marrow [1] importance of NK cells in anti-viral immunity was first demonstrated by the discovery that patients with a congenital deficiency of NK cells have overwhelming viral infections [2]