<prompt> All of the following statements about NK cells are true except:They are derived from large granular cellsThey comprise about 5 of human peripheral lymphoid cellsThey are MHC restricted cytotoxic cellsThey express IgG Fc receptors  <response>: NK cells are innate immune cells They are functional without prior activation and do not express highly variable and clonally distributed receptors for antigens. NK cells have two types of receptors-- Inhibitory and Activating. They are capable of MHC - unrestricted direct cell lysis which is not mediated by an immune response. 