Structural basis for enabling T-cell receptor diversity within biased virus-specific CD8+ T-cell responses.

ABSTRACT: Pathogen-specific responses are characterized by preferred profiles of peptide+class I MHC (pMHCI) glycoprotein-specific T-cell receptor (TCR) Variable (V)-region use. How TCRV-region bias impacts TCR?? heterodimer selection and resultant diversity is unclear. The D(b)PA(224)-specific TCR repertoire in influenza A virus-infected C57BL/6J (B6) mice exhibits a preferred TCRV-region bias toward the TRBV29 gene segment and an optimal complementarity determining region (CDR3) ?-length of 6 aa. Despite these restrictions, D(b)PA(224)-specific BV29(+) T cells use a wide array of unique CDR3? sequences. Structural characterization of a single, TRBV29(+)D(b)P(A224)-specific TCR??-pMHCI complex demonstrated that CDR3? amino acid side chains made specific peptide interactions, but the CDR3? main chain exclusively contacted peptides. Thus, length but not amino acid sequence was key for recognition and flexibility in V?-region use. In support of this hypothesis, retrovirus expression of the D(b)PA(224)-specific TCRV?-chain was used to constrain pairing within a naive/immune epitope-specific repertoire. The retrogenic TCRV? paired with a diversity of CDR3?s in the context of a preferred TCRV? spectrum. Overall, these data provide an explanation for the combination of TCRV region bias and diversity within selected repertoires, even as they maintain exquisite pMHCI specificity.

SUBMITTER: Day EB 

PROVIDER: S-EPMC3111262 | biostudies-literature | 2011 Jun

REPOSITORIES: biostudies-literature