<prompt> N.K. cell and cytotoxic cells are differentiated by ?Interferons reduce N.K. cell activityAntibody specificityReceptor for IgGPresence in spleen  <response>: Ans. is b i.e., Antibody specificity . Cytotoxicity of NK cells is not antibody dependent or MHC restricted, while cytotoxic cells are capable of lysing or killing target cells sensitized with antibody. 