One way NK cells can cause cell destruction is by expressing cytotoxic membrane proteins and cytokines that makes the target cell undergo apoptosis. Another way NK cells acts is by undergoing perforin mediated cytotoxicity using perforin and granzymes, which pokes holes in the target cells and enter the cell to stimulate apoptosis, respectively. NK cells have toxic granules but are not considered granulocytes, instead coming from lymphoid (rather than myeloid stem) cells.

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