Engineering the binding properties of the T cell receptor:peptide:MHC ternary complex that governs T cell activity

Natalie A. Bowerman, Terence Spencer Crofts, Lukasz Chlewicki, Priscilla Do, Brian M. Baker, K. Christopher Garcia, David M. Kranz*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

The potency of a T cell is determined in large part by two interactions, binding of a cognate peptide to the MHC, and binding of the T cell receptor (TCR) to this pepMHC. Various studies have attempted to assess the relative importance of these interactions, and to correlate the corresponding binding parameters with the level of T cell activity mediated by the peptide. To further examine the properties that govern optimal T cell activity, here we engineered both the peptide:MHC interaction and the TCR:pepMHC interaction to generate improved T cell activity. Using a system involving the 2C TCR and its allogeneic pepMHC ligand, QL9-Ld, we show that a peptide substitution of QL9 (F5R), increased the affinity and stability of the pep-Ld complex (e.g. cell surface t1/2-values of 13 min for QL9-Ld versus 87 min for F5R-Ld). However, activity of peptide F5R for 2C T cells was not enhanced because the 2C TCR bound with very low affinity to F5R-Ld compared to QL9-Ld (KD = 300 μM and KD = 1.6 μM, respectively). To improve the affinity, yeast display of the 2C TCR was used to engineer two mutant TCRs that exhibited higher affinity for F5R-Ld (KD = 1.2 and 6.3 μM). T cells that expressed these higher affinity TCRs were stimulated by F5R-Ld in the absence of CD8, and the highest affinity TCR exhibited enhanced activity for F5R compared to QL9. The results provide a guide to designing the explicit binding parameters that govern optimal T cell activities.

Original languageEnglish (US)
Pages (from-to)3000-3008
Number of pages9
JournalMolecular Immunology
Volume46
Issue number15
DOIs
StatePublished - Sep 2009

Keywords

  • Antigen presentation
  • Immunogenicity
  • MHC
  • Peptide variants
  • T cell receptor

ASJC Scopus subject areas

  • Immunology
  • Molecular Biology

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