T cell receptor alpha beta (TCR alpha beta)

The T cell receptor alpha beta (TCR alpha beta) is a disulfide-linked heterodimeric protein complex found on the surface of approximately 95% of circulating T cells. Its primary biological function is the recognition of specific antigenic peptides presented by Major Histocompatibility Complex (MHC) molecules on the surface of antigen-presenting cells or infected/malignant cells (UniProt, 2024). Upon binding to a peptide-MHC complex, the TCR alpha beta initiates a signal transduction cascade through the associated CD3 complex, leading to T cell activation, proliferation, and the execution of effector functions such as cytokine release or direct cytotoxicity (PubMed, 2023). In the context of disease, the TCR alpha beta is a critical driver of autoimmune disorders when it recognizes self-antigens and is the primary mediator of graft-versus-host disease in transplantation (StatPearls, 2024). Conversely, in oncology, the TCR is a major therapeutic target for TCR-engineered T-cell (TCR-T) therapies, such as Afamitresgene autoleucel, which are designed to redirect the immune system to recognize and eliminate solid tumors (FDA, 2024). Therapeutic modulation of the TCR alpha beta also includes the use of monoclonal antibodies and bispecific engagers that target the TCR/CD3 complex to treat conditions ranging from organ rejection to hematologic malignancies (DrugBank, 2024).

Other names

TCR alpha/betaAlpha-beta T-cell receptorTCRabT-cell antigen receptor alpha/beta

The TCR alpha beta recognizes specific peptide-MHC complexes, triggering a conformational change that activates the associated CD3 signaling subunits, leading to T-cell activation and effector functions (PubMed, 2023).