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

Mol Immunol. 2009 Sep;46(15):3000-8. doi: 10.1016/j.molimm.2009.06.012.


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-L(d), we show that a peptide substitution of QL9 (F5R), increased the affinity and stability of the pep-L(d) complex (e.g. cell surface t(1/2)-values of 13 min for QL9-L(d) versus 87 min for F5R-L(d)). However, activity of peptide F5R for 2C T cells was not enhanced because the 2C TCR bound with very low affinity to F5R-L(d) compared to QL9-L(d) (K(D)=300 microM and K(D)=1.6 microM, respectively). To improve the affinity, yeast display of the 2C TCR was used to engineer two mutant TCRs that exhibited higher affinity for F5R-L(d) (K(D)=1.2 and 6.3 microM). T cells that expressed these higher affinity TCRs were stimulated by F5R-L(d) 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.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Cell Line
  • Cloning, Molecular
  • Major Histocompatibility Complex / immunology*
  • Mice
  • Peptides / genetics
  • Peptides / immunology*
  • Peptides / metabolism
  • Protein Binding
  • Protein Conformation
  • Protein Engineering
  • Receptors, Antigen, T-Cell / genetics
  • Receptors, Antigen, T-Cell / immunology
  • Receptors, Antigen, T-Cell / metabolism*
  • Surface Plasmon Resonance
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / metabolism
  • Transfection


  • Peptides
  • Receptors, Antigen, T-Cell