Amino acid residues that are critical in maintaining the framework structure of immunoglobulin heavy- and light-chain variable (V) regions are strongly conserved in the Vα and Vβ proteins of the αβ T-cell antigen receptor (TCRαβ). Consequently, it has been proposed that TCRαβ has a conformation similar to that of an immunoglobulin Fab fragment and that the regions of the TCR homologous to the three immunoglobulin complementarity- determining regions (CDRs 1, 2, and 3) bind to the peptide antigen-major histocompatibility complex (MHC) molecule ligand. A single amino acid substitution in the predicted CDR1 of the Vβ3 protein of certain mouse strains dramatically altered TCRαβ usage in an antigen-specific MHC- restricted immune response but did not abrogate Vβ3 specificity for the superantigens minor lymphocyte stimulatory locus (Mls)(c) and staphylococcal enterotoxin A (SEA). The results confirm the importance of the Vβ CDR1 in antigen-MHC molecule recognition, supporting the Fab-like structural model of TCRαβ, and provide further evidence that conventional antigen-MHC recognition and superantigen recognition are mediated by distinct regions of the TCR β chain. They also suggest that allelic polymorphism may be a significant source of diversity in the TCR repertoire.
|Original language||English (US)|
|Number of pages||5|
|Journal||Proceedings of the National Academy of Sciences of the United States of America|
|State||Published - 1991|
- T-cell antigen recognition
- allelic polymorphism