Natural Killer Cell (None)

Natural killer cells (NK cells) are cytotoxic lymphocytes of the innate immune system that provide rapid responses to virus-infected and malignant cells. Their activity is regulated by a balance of activating and inhibitory receptor signals. NK cells kill target cells through the release of lytic granules and cytokine secretion, and they mediate antibody-dependent cellular cytotoxicity (ADCC).

NK cells recognize and kill target cells through a balance of activating and inhibitory receptor signals. Activating receptors recognize stress-induced ligands, while inhibitory receptors recognize MHC-I. Lack of MHC-I or strong activating signals trigger the release of cytotoxic granules containing perforin and granzymes, leading to target cell apoptosis. CD16 (FcγRIIIa) mediates ADCC.