High-affinity, peptide-specific T cell receptors can be generated by mutations in CDR1, CDR2 or CDR3

Lukasz K. Chlewicki, Phillip D. Holler, Bridget C. Monti, Matthew R. Clutter, David M. Kranz*

*Corresponding author for this work

Research output: Contribution to journalArticle

69 Scopus citations

Abstract

The third complementarity-determining regions (CDR3s) of antibodies and T cell receptors (TCRs) have been shown to play a major role in antigen binding and specificity. Consistent with this notion, we demonstrated previously that high-affinity, peptide-specific TCRs could be generated in vitro by mutations in the CDR3α region of the 2C TCR. In contrast, it has been argued that CDR1 and CDR2 are involved to a greater extent than CDR3s in the process of MHC restriction, due to their engagement of MHC helices. Based on this premise, we initiated the present study to explore whether higher affinity TCRs generated through mutations in these CDRs or other regions would lead to significant reductions in peptide specificity (i.e. the result of greater binding energy gained through interactions with major histocompatibility complex (MHC) helices). Yeast-display technology and flow sorting were used to select high-affinity TCRs from libraries of CDR mutants or random mutants. High-affinity TCRs with mutations in the first residue of the Vα, CDR1, CDR2, or CDR3 were isolated. Unexpectedly, every TCR mutant, including those in CDR1 and CDR2, retained remarkable peptide specificity. Molecular modeling of various mutants suggested that such exquisite specificity may be due to: (1) enhanced electrostatic interactions with key peptide or MHC residues; or (2) stabilization of CDRs in specific conformations. The results indicate that the TCR is positioned so that virtually every CDR can contribute to the antigen-specificity of a T cell. The conserved diagonal docking of TCRs could thus orient each CDR loop to sense the peptide directly or indirectly through peptide-induced effects on the MHC.

Original languageEnglish (US)
Pages (from-to)223-239
Number of pages17
JournalJournal of Molecular Biology
Volume346
Issue number1
DOIs
StatePublished - Feb 11 2005

Keywords

  • T cell receptors
  • antigen recognition
  • protein engineering
  • yeast display

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

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