Cancer Immunology, Immunotherapy

, Volume 53, Issue 4, pp 307–314

Her-2/neu altered peptide ligand–induced CTL responses: implications for peptides with increased HLA affinity and T-cell-receptor interaction

  • Sara O. Dionne
  • Cheryl E. Myers
  • Margaret H. Smith
  • Douglas F. Lake
Original Article

Abstract

In this study, we developed two Her-2/neu-derived E75 altered peptide ligands (APLs) that demonstrate increased affinities for the HLA-A*0201 allele compared with wild-type E75 peptide. The APLs contain amino acids from E75(369–377), an immunodominant Her-2/neu-derived peptide, and preferred primary and auxiliary HLA-A*0201 molecule anchor residues previously identified from combinatorial peptide library screening with the recombinant molecule. CTL lines were generated against wild-type E75 peptide (KIFGSLAFL) and APLs by multiple rounds of peptide stimulation of peripheral blood mononuclear cells (PBMCs) from HLA-A2+ antigen normal individuals. CTL lines raised on wild-type E75 peptide cross-reacted with APLs and similarly, CTL lines raised on APLs cross-reacted with wild-type E75 peptide, as measured by IFN-γ ELISpot and target cell lysis assays. One of five individuals demonstrated specificity for APL 2 (FLFGSLAFL), whereas APL 5 (FLFESLAFL)-specific responses were observed from all five individuals tested. Molecular models of the E75, APL 2, and APL 5/HLA-A2 complexes indicated that the substitution of glycine with glutamic acid at position four of APL 5 resulted in the presentation of a large, negatively charged side chain that interacts with the outer edge of the HLA-A2 antigen alpha helix and is freely available to interact with cognate T-cell receptors. The results of this study further substantiate the concept that rational design of T-cell epitopes may lead to stronger peptide immunogens than natural, wild-type peptides.

Keywords

Her-2/neu Altered peptide ligand (APL) Cytotoxic T lymphocyte (CTL) Human leukocyte antigen (HLA) T-cell receptor (TCR) 

Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  • Sara O. Dionne
    • 1
  • Cheryl E. Myers
    • 1
  • Margaret H. Smith
    • 2
  • Douglas F. Lake
    • 1
  1. 1.Department of Microbiology and Immunology, Arizona Cancer CenterUniversity of ArizonaTucsonUSA
  2. 2.Department of BiochemistryUniversity of ArizonaTucsonUSA

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