NKG2D ligands (NKG2DL)

NKG2D ligands (NKG2DLs) are a group of cell surface glycoproteins, including MICA, MICB, and the ULBP family, that are typically absent from healthy cells but become highly expressed under conditions of cellular stress, such as malignancy or viral infection [Nature Reviews Immunology, 2008]. These ligands serve as critical recognition signals for the activating receptor NKG2D, which is found on natural killer (NK) cells and various T cell subsets, thereby triggering an immune-mediated attack against the stressed cells [Frontiers in Immunology, 2019]. In the context of oncology, many tumors employ immune evasion strategies by shedding these ligands from their surface through proteolytic cleavage, resulting in soluble forms that can desensitize the NKG2D receptor and impair immune surveillance [Science, 2018]. Therapeutic development focuses on several modalities, including monoclonal antibodies designed to stabilize surface expression by preventing shedding, bispecific antibodies that engage NK cells, and CAR-T or CAR-NK cells engineered to target the broad array of NKG2DLs present on tumor surfaces [Journal of Hematology & Oncology, 2019]. Clinical trials are currently evaluating these approaches across various solid and hematological malignancies, with a focus on overcoming the challenges posed by the immunosuppressive tumor microenvironment and ligand shedding [Clinical Cancer Research, 2018].

Other names

MICAMICBULBPStress-induced ligandsMIC ligandsRAET1MHC class I polypeptide-related sequence AMHC class I polypeptide-related sequence B

Activation of NKG2D-mediated cytotoxicity, prevention of proteolytic shedding of MICA/B, and direct targeting of ligand-expressing cells via CAR-based therapies.