Natural cytotoxicity triggering receptor 1 ligand (NCR1 ligand) (NCR1-L)

NCR1 ligands on target cells are a heterogeneous group of molecules that serve as the primary triggers for the Natural Cytotoxicity Triggering Receptor 1 (NCR1), also known as NKp46, which is a defining activating receptor constitutively expressed on all Natural Killer (NK) cells (Arnon et al., 2001, PMID: 11248435). These ligands include viral proteins like influenza hemagglutinin, bacterial surface proteins such as Fap2 from Fusobacterium nucleatum, and various endogenous molecules that are upregulated or modified on the surface of tumor cells or stressed cells, such as heparan sulfate proteoglycans and calreticulin (Sen Santara et al., 2023, PMID: 37316664). The recognition of these ligands by NKp46 is a critical step in the innate immune system's ability to identify and eliminate aberrant cells without prior sensitization. In the context of modern immunotherapy, the interaction between NCR1 and its ligands is being bypassed or augmented by multi-specific antibodies known as NK cell engagers (e.g., SAR443579). These therapeutic agents bind to NKp46 on the NK cell and a specific tumor-associated antigen on the target cell, mimicking the natural ligand-induced activation to promote potent anti-tumor cytotoxicity (Gauthier et al., 2019, PMID: 31142854). Understanding the identity and regulation of these ligands is essential for predicting NK cell efficacy and developing next-generation cancer immunotherapies that leverage the innate power of NK cells.

Other names

NKp46 ligandNKp46-LNCR1-LNatural killer cell p46-related protein ligandNKp46-binding molecules

Drugs targeting this pathway typically function as multi-specific NK cell engagers that bind to the NCR1 (NKp46) receptor on NK cells and a specific antigen on the target cell (e.g., CD123 or BCMA), effectively creating a synthetic ligand-receptor interaction to trigger NK cell-mediated lysis (Gauthier et al., 2019, PMID: 31142854).