Editing Natural killer cell (section)

===Cytolytic granule mediated cell apoptosis===
NK cells are [[cytotoxic]]; small [[Granulocytes|granules]] in their [[cytoplasm]] contain proteins such as [[perforin]] and [[protease]]s known as [[granzyme]]s. Upon release in close proximity to a cell slated for killing, perforin forms pores in the [[cell membrane]] of the target cell, creating an aqueous channel through which the granzymes and associated molecules can enter, inducing either [[apoptosis]] or osmotic cell lysis. The distinction between apoptosis and cell [[lysis]] is important in [[immunology]]: lysing a virus-infected cell could potentially release the [[virion]]s, whereas apoptosis leads to destruction of the virus inside. [[Alpha defensin|α-defensins]], antimicrobial molecules, are also secreted by NK cells, and directly kill bacteria by disrupting their cell walls in a manner analogous to that of [[neutrophil]]s.<ref name=Lannello2008/>