T-Cell Receptor Delta (TCRd)

Two distinct types of T-cell antigen receptors have been identified: the alpha/beta heterodimer found on functional helper and cytotoxic T cells, and the gamma/delta heterodimer. In adult thymus it is found mainly in the least mature cells. The gene shows systematic rearrangement in early thymocytes and appears to use V-gene segments of the TCR alpha-chain family, well before any C(alpha) message of protein is detected. TCRD was rearranged in a gamma/delta-expressing T-cell line and was deleted in alpha/beta-expressing T-cell lines. TCRD gene is located in 14q11 came from analysis of the translocation t(8;14)(q24;q11) from a T-cell leukemia: the J(delta) segment was rearranged in cells derived from this tumor and was probably involved in the translocation.