TY - JOUR TI - The somatically generated portion of T cell receptor CDR3α contributes to the MHC allele specificity of the T cell receptor AU - Marrack, Philippa AU - Krovi, Sai Harsha AU - Silberman, Daniel AU - White, Janice AU - Kushnir, Eleanor AU - Nakayama, Maki AU - Crooks, James AU - Danhorn, Thomas AU - Leach, Sonia AU - Anselment, Randy AU - Scott-Browne, James AU - Gapin, Laurent AU - Kappler, John A2 - Bjorkman, Pamela J VL - 6 PY - 2017 DA - 2017/11/17 SP - e30918 C1 - eLife 2017;6:e30918 DO - 10.7554/eLife.30918 UR - https://doi.org/10.7554/eLife.30918 AB - Mature T cells bearing αβ T cell receptors react with foreign antigens bound to alleles of major histocompatibility complex proteins (MHC) that they were exposed to during their development in the thymus, a phenomenon known as positive selection. The structural basis for positive selection has long been debated. Here, using mice expressing one of two different T cell receptor β chains and various MHC alleles, we show that positive selection-induced MHC bias of T cell receptors is affected both by the germline encoded elements of the T cell receptor α and β chain and, surprisingly, dramatically affected by the non germ line encoded portions of CDR3 of the T cell receptor α chain. Thus, in addition to determining specificity for antigen, the non germline encoded elements of T cell receptors may help the proteins cope with the extremely polymorphic nature of major histocompatibility complex products within the species. KW - T cell receptor KW - major histocompatibility complex KW - CDR3 alpha KW - thymus KW - selection JF - eLife SN - 2050-084X PB - eLife Sciences Publications, Ltd ER -