Structure and Diversity of the Human T-Cell Receptor β-Chain Variable Region Genes

Publisher Website
Google Scholar
Abstract
In order to characterize the variability of the expressed human T-cell receptor (TCR) β-chain repertoire and contrast this variability to the known murine β-chain repertoire, 15 independent complementary DNA (cDNA) clones containing TCR β-chain variable region (V β ) genes were isolated from a human tonsil cDNA library. The nucleotide and derived amino acid sequences of these 15 V β genes were analyzed together with 7 previously defined sequences. Fifteen different human V β genes could be identified from 22 independent sequences. By means of DNA hybridization and sequence homology comparisons, it was possible to group these 15 genes into ten distinct V β subfamilies, each containing from one to seven members. Minimal polymorphism was noted between individuals, except in multimember subfamilies. The amino acid sequences of these genes contain conserved amino acids that are also shared by murine TCR V β genes and immunoglobulins; no features were found that distinguish human V β genes from their murine counterparts. Evaluation of secondary structure showed that maximum variability coincides with generally hydrophilic portions of the amino acid sequence, while specific hydrophobic regions were conserved in all V β genes examined.