Single amino acid replacements in an antigenic peptide are sufficient to alter the TCR Vβ repertoire of the responding CD8+ cytotoxic lymphocyte population

Alexis M. Kalergis, Toshiro Ono, Fuming Wang, Teresa P. DiLorenzo, Shinichiro Honda, Stanley G. Nathenson

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Abstract

Cytotoxic CD8+ T lymphocytes are activated upon the engagement of their Ag-specific receptors by MHC class I molecules loaded with peptides 8-11 amino acids long. T cell responses triggered by certain antigenic peptides are restricted to a limited number of TCR Vβ elements. The precise role of the peptide in causing this restricted TCR Vβ expansion in vivo remains unclear. To address this issue, we immunized C57BL/6 mice with the immunodominant peptide of the vesicular stomatitis virus (VSV) and several peptide variants carrying single substitutions at TCR-contact residues. We observed the expansion of a limited set of TCR Vβ elements responding to each peptide variant. To focus our analysis solely on the TCR β-chain, we created a transgenic mouse expressing exclusively the TCR α-chain from a VSV peptide-specific CD8+ T cell clone. These mice showed an even more restricted TCR Vβ usage consequent to peptide immunization. However, in both C57BL/6 and TCRα transgenic mice, single amino acid replacements in TCR- contact residues of the VSV peptide could alter the TCR Vβ usage of the responding CD8+ T lymphocytes. These results provide in vivo evidence for an interaction between the antigenic peptide and the germline-encoded complementarity-determining region-β loops that can influence the selection of the responding TCR repertoire. Furthermore, only replacements at residues near the C terminus of the peptide were able to alter the TCR Vβ usage, which is consistent with the notion that the TCR β-chain interacts in vivo preferentially with this region of the MHC/peptide complex.

Original languageEnglish (US)
Pages (from-to)7263-7270
Number of pages8
JournalJournal of Immunology
Volume162
Issue number12
Publication statusPublished - Jun 15 1999

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ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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