title: The natural killer cell.
mesh_terms: D000818:Animals; D004777:Environment; D006801:Humans; D007111:Immunity, Cellular; D007157:Immunologic Surveillance; D007694:Killer Cells, Natural / Q000276:immunology* / Q000502:physiology / Q000648:ultrastructure; D051379:Mice; D009369:Neoplasms / Q000276:immunology*; D051381:Rats; D012190:Retroviridae / Q000502:physiology