Natural killer cell

(NKC, NK cell); large granular lymphocyte which does not express markers of either T or B cell lineage

Description
These cells do possess Fc receptors for IgG and can kill target cells using antibody-dependent cell-mediated cytotoxicity. NK cells can also use perforin to kill cells in the absence of antibody. Killing occurs without previous sensitization, but although viewed as part of the innate immune system, NK cells have memory function as well and are more protective on second encounter with a pathogen, apparently brought about by a greater effector function, rather than by greater proliferation. Syn NK cell