Allelic polymorphism of human T-cell receptor V alpha gene segments

Recognition of peptide Major histocompatibility complexes (MHCs) by the T-cell receptor (Tcr) represents a critical event both in the development of T-cell tolerance and in the induction of a specific immune response. The repertoire of expressed Tcr required to recognize a wide spectrum of MHC-peptide complexes results mainly from the rearrangement of multiple V, D, and J gene segments, combined with the process of N-region addition/deletion during rearrangement of T-cell receptor genes. However, an additional source of variation, allelic polymorphism of Tcr gene segments may also play an important role in the generation of diversity within the T-cell repertoire. Restriction fragment length polymorphism (RFLP) analyses have suggested the existence of a small number of alleles for most Tcr-V region genes, but coding region polymorphisms have been identified in only a limited number of Tcr-V genes.