Natural killer cell stress-induced ligands (NKG2DL) (NKG2DL)

Natural killer cell stress-induced ligands (NKG2DLs) are a group of cell surface proteins, including MHC class I polypeptide-related sequence A (MICA), MICB, and the UL16-binding protein (ULBP) family, that are upregulated on host cells in response to cellular stress, DNA damage, or malignant transformation (PMID: 21739672). These ligands serve as critical recognition signals for the immune system by binding to the activating receptor NKG2D (KLRK1) expressed on Natural Killer (NK) cells and certain T cell subsets (UniProt: P43481, Q29980). Binding triggers the activation of effector cells, leading to the targeted destruction of the stressed or transformed host cell through the release of cytotoxic granules (PMID: 11777960). In many cancers, tumors utilize proteolytic shedding of these ligands (e.g., sMICA) as an immune evasion mechanism to desensitize effector cells and avoid detection (PMID: 12191486). Therapeutic strategies currently in development include NKG2D-based CAR-T cells (e.g., CYAD-01), monoclonal antibodies that stabilize ligand expression or prevent shedding (e.g., 7C6), and bispecific engagers designed to bridge NKG2DL-expressing cells with immune effectors (PMID: 29590616, PMID: 31110293).

Other names

NKG2D ligandsStress-induced ligandsMHC class I polypeptide-related sequence AMHC class I polypeptide-related sequence BMICAMICBUL16-binding proteinsULBPsRAET1 proteins

Binding to the activating NKG2D receptor on effector lymphocytes to trigger cytotoxic granule release and cytokine production against ligand-expressing cells (PMID: 11777960).