Gamma-delta T-cell receptor ligands (γδ TCR ligands)

Gamma-delta (γδ) T-cell receptor ligands are a diverse group of molecules expressed on the surface of tumor or stressed cells that are recognized by γδ T cells in a major histocompatibility complex (MHC)-independent manner [1, 15]. The most well-characterized ligands include members of the butyrophilin family, specifically BTN3A1 and BTN2A1, which are essential for the activation of Vγ9Vδ2 T cells, the predominant γδ T-cell subset in human blood [3, 9]. Other significant ligands include MHC class I-related molecules (MICA and MICB) and UL16-binding proteins (ULBPs), which serve as stress signals upregulated during malignant transformation [6, 11]. These ligands allow γδ T cells to rapidly identify and eliminate tumor cells through the secretion of cytotoxic granules and pro-inflammatory cytokines like IFN-γ [17, 21]. In therapeutic development, these ligands are targeted by aminobisphosphonates to induce phosphoantigen accumulation or by monoclonal and bispecific antibodies that stabilize active ligand conformations to enhance anti-tumor immunity [4, 18]. Understanding the interaction between these ligands and the γδ TCR is critical for the design of next-generation immunotherapies that bypass the limitations of traditional MHC-restricted T-cell therapies [13, 20].

Other names

Tumor cell ligands for γδ TCRγδ T-cell receptor ligandsButyrophilin-like ligandsStress-induced ligandsNon-classical MHC ligandsPhosphoantigen-presenting molecules

Activation of γδ T cells through the modulation or direct engagement of surface ligands such as BTN3A1 and MICA/B, facilitating MHC-independent tumor cell lysis.