Background：T cell receptor （TCR） is a heterodimer consisting of an a and a b chain （TCR a/b） or a gamma and a delta chain （TCR gamma/delta）. TCR gamma/delta belongs to the immunoglobulin superfamily, involved in the recognition of certain bacterial and tumor antigens bound to MHC class I. The TCR gamma/delta associates with CD3 and is expressed on a T cell subset found in the thymus, the intestinal epithelium, and the peripheral lymphoid tissues and peritoneum. Most gamma/delta T cells are CD4-/CD8-, some are CD8+. T cells expressing the TCR gamma/delta have been shown to play a role in oral tolerance, tumor-associated tolerance, and autoimmune disease. It has been reported that gamma/delta T cells also play a principal role in antigen presentation. Immobilized UC7-13D5 antibody has been reported to activate TCR-gamma/delta-bearing T cells in vitro, and to deplete peripheral TCR-gamma/delta-bearing T cells in vivo.
