DETECTION OF A T-CELL RECEPTOR DELTA-CHAIN WITH AN ANTI-TCR-ALPHA-CHAIN SERUM

Two types of T cell antigen-specific receptors have been described. Most peripheral blood T lymphocytes express, at their surface, an antigen receptor consisting of α and β subunits, while a small subset of thymocytes and a minority of mature T lymphocytes express a heterodimeric receptor termed γδ. Whereas the gene segments localization corresponding to the TCR γ and β chains are separate, genes encoding the joining and the constant regions of TCR δ chain are located between the TCR Vα region and the Jα-Cα gene cluster. To determine whether Vα gene segments are used by δ chains, immunoprecipitations from human TCR γδ expressing cell clones were performed with an anti-α serum. The results show that a rabbit antiserum raised against the purified REX TCR α subunit immunoprecipitates a TCR δ chain from the cell surface of only one human T cell clone termed SO1. However, since no SO1 RNA hybridization is observed with REX TCR Vα probe and SO1 cloned cells do react with an anti-Vδ2 monoclonal antibody, we conclude that TCR δ and α chains expressed a limited structural homology and that REX TCR Vα gene do not seem to be frequently used in a functional δ chain. © 1990.