Natural Killer Receptor

Natural killer (NK) receptors are a diverse group of cell surface proteins found primarily on natural killer cells, a type of cytotoxic lymphocyte critical to the innate immune system. These receptors play a central role in regulating NK cell activity by integrating signals that determine whether an NK cell will kill or spare a target cell. NK receptors mediate the recognition and destruction of virus-infected, stressed, or malignant cells by NK cells. They function as both activating and inhibitory regulators. The balance between these opposing signals determines if the NK cell will initiate cytotoxicity against the target. Activating receptors recognize stress-induced ligands on abnormal cells, while inhibitory receptors typically recognize self-molecules such as MHC class I to prevent autoimmunity.

Therapeutic manipulation is under investigation for cancer immunotherapy—either enhancing activation or blocking inhibition to boost anti-tumor responses.