All of the following statements about NK cells are true except:
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.
They are derived from large granular cells
They comprise about 5% of human peripheral lymphoid cells
They are MHC restricted cytotoxic cells
They express IgG Fc receptors
Immunology