The γδ T-cell receptor (TCR) is a heterodimer composed of γ and δ chains, expressed on the surface of T cells and involved in antigen recognition. The engagement of γδ TCR with antigen triggers phosphorylation of immunoreceptor tyrosine-based activation motifs (ITAMs) within the CD3 chains. Unlike αβ T cells, human γδ T cells recognize and kill transformed cells in an HLA-unrestricted manner. γδ T lymphocytes develop primarily in the thymus, where their definitive receptor is generated through RAG-mediated rearrangement of a limited repertoire of variable (V), diversity (D), and joining (J) gene segments. In addition to the T-cell receptor, γδ T cells often express activating natural killer (NK) receptors that bind to stress-induced surface molecules frequently expressed on malignant cells.
