Singolo Linfocita NK, cellula immunitaria ((Credit foto: Wikimedia – NIAID, ” https://commons.wikimedia.org/wiki/File:Human_Natural_Killer_Cell_(29120480442).jpg”, ridimensionata, dimensioni: 800×700 px, CC BY 2.0, “https://creativecommons.org/licenses/by/2.0/deed.en”).