Natural Cytotoxicity Receptor NKp46, also known as NCR1, is a key activating receptor found on the surface of Natural Killer (NK) cells. It belongs to the family of Ig-like activation receptors known as Natural Cytotoxicity Receptors (NCRs), which also includes NKp30 and NKp44 . NKp46 is unique among NCRs as it has a mouse orthologue, making it a critical molecule for studying NK cell functions in both human and murine models .
NKp46 plays a crucial role in the immune system’s ability to recognize and eliminate tumor cells and virus-infected cells. It is almost exclusively expressed by NK cells and is involved in triggering key lytic activities of these cells . The receptor can bind to various ligands present on the surface of target cells, leading to the activation of NK cells and subsequent cytotoxic responses .
The activation of NKp46 leads to the initiation of signaling pathways that result in the release of cytotoxic granules and cytokines by NK cells. This process is essential for the destruction of target cells that lack sufficient levels of MHC class I molecules, which are typically spared from NK cell attack . The receptor’s ability to recognize and bind to non-MHC class I ligands on target cells is a key feature of its function .
The expression and activity of NKp46 are tightly regulated to ensure that NK cells can effectively distinguish between healthy cells and abnormal cells. This regulation involves various signaling molecules and pathways that modulate the receptor’s activity in response to different stimuli . Additionally, NKp46 can be co-expressed with other NK cell markers, such as NK1.1 in mice, which further influences its function and regulation .
NKp46 has been extensively studied for its potential therapeutic applications, particularly in the context of cancer immunotherapy. Humanized NKp46 mouse models have been developed to evaluate novel anti-NKP46-targeting drugs and their efficacy in vivo . These models are valuable tools for understanding the role of NKp46 in tumor surveillance and for developing new therapeutic strategies .