The transmembrane protein, TCR, comprise of two disulphide-linked polypeptide chains: a α and β chain, a γ and δ chain. Each polypeptide chain consists of a variable and a constant region. TRAC is the constant region of T-cell receptor (TCR) alpha chain. TRAC is presented on the surface of T cell and recognized peptide-major histocompatibility (MH) (pMH) that are displayed by antigen presenting cells (APC). TRAC is participate in adaptive immune response and has been well-studied in T cell therapy.