Positional scanning-synthetic peptide library-based analysis of self- and pathogen-derived peptide cross-reactivity with tumor-reactive Melan-A-specific CTL

J Immunol. 2002 Nov 15;169(10):5696-707. doi: 10.4049/jimmunol.169.10.5696.

Abstract

Synthetic combinatorial peptide libraries in positional scanning format (PS-SCL) have recently emerged as a useful tool for the analysis of T cell recognition. This includes identification of potentially cross-reactive sequences of self or pathogen origin that could be relevant for the understanding of TCR repertoire selection and maintenance, as well as of the cross-reactive potential of Ag-specific immune responses. In this study, we have analyzed the recognition of sequences retrieved by using a biometric analysis of the data generated by screening a PS-SCL with a tumor-reactive CTL clone specific for an immunodominant peptide from the melanocyte differentiation and tumor-associated Ag Melan-A. We found that 39% of the retrieved peptides were recognized by the CTL clone used for PS-SCL screening. The proportion of peptides recognized was higher among those with both high predicted affinity for the HLA-A2 molecule and high predicted stimulatory score. Interestingly, up to 94% of the retrieved peptides were cross-recognized by other Melan-A-specific CTL. Cross-recognition was at least partially focused, as some peptides were cross-recognized by the majority of CTL. Importantly, stimulation of PBMC from melanoma patients with the most frequently recognized peptides elicited the expansion of heterogeneous CD8(+) T cell populations, one fraction of which cross-recognized Melan-A. Together, these results underline the high predictive value of PS-SCL for the identification of sequences cross-recognized by Ag-specific T cells.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Antigens, Bacterial / immunology*
  • Antigens, Bacterial / metabolism
  • Antigens, Neoplasm / immunology
  • Antigens, Neoplasm / metabolism
  • Antigens, Viral / immunology*
  • Antigens, Viral / metabolism
  • Autoantigens / immunology*
  • Autoantigens / metabolism
  • Clone Cells
  • Combinatorial Chemistry Techniques / methods*
  • Cytotoxicity Tests, Immunologic / methods
  • Cytotoxicity, Immunologic*
  • Epitopes, T-Lymphocyte / immunology
  • Epitopes, T-Lymphocyte / metabolism
  • HLA-A2 Antigen / metabolism
  • Humans
  • MART-1 Antigen
  • Melanoma / immunology
  • Neoplasm Proteins / immunology*
  • Neoplasm Proteins / metabolism
  • Peptide Fragments / analysis
  • Peptide Fragments / chemical synthesis
  • Peptide Fragments / immunology
  • Peptide Library*
  • Protein Binding / immunology
  • T-Lymphocytes, Cytotoxic / immunology*
  • T-Lymphocytes, Cytotoxic / metabolism
  • Tumor Cells, Cultured

Substances

  • Antigens, Bacterial
  • Antigens, Neoplasm
  • Antigens, Viral
  • Autoantigens
  • Epitopes, T-Lymphocyte
  • HLA-A2 Antigen
  • MART-1 Antigen
  • MLANA protein, human
  • Neoplasm Proteins
  • Peptide Fragments
  • Peptide Library