Proteasome-assisted identification of a SSX-2-derived epitope recognized by tumor-reactive CTL infiltrating metastatic melanoma

J Immunol. 2002 Feb 15;168(4):1717-22. doi: 10.4049/jimmunol.168.4.1717.


The tumor Ag SSX-2 (HOM-MEL-40) was found by serological identification of Ags by recombinant expression cloning and was shown to be a cancer/testis Ag expressed in a wide variety of tumors. It may therefore represent a source of CD8(+) T cell epitopes useful for specific immunotherapy of cancer. To identify potential SSX-2-derived epitopes that can be recognized by CD8(+) T cells, we used an approach that combined: 1) the in vitro proteasomal digestion of precursor peptides overlapping the complete SSX-2 sequence; 2) the prediction of SSX-2-derived peptides with an appropriate HLA-A2 binding score; and 3) the analysis of a tumor-infiltrated lymph node cell population from an HLA-A2(+) melanoma patient with detectable anti-SSX-2 serum Abs. This strategy allowed us to identify peptide SSX-2(41-49) as an HLA-A2-restricted epitope. SSX2(41-49)-specific CD8(+) T cells were readily detectable in the tumor-infiltrated lymph node population by multimer staining, and CTL clones isolated by multimer-guided cell sorting were able to lyse HLA-A2(+) tumor cells expressing SSX-2.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antigens, Neoplasm / chemistry
  • Antigens, Neoplasm / immunology*
  • COS Cells
  • Clone Cells
  • Cysteine Endopeptidases / metabolism*
  • Cytotoxicity Tests, Immunologic
  • Epitope Mapping
  • Epitopes, T-Lymphocyte / immunology*
  • HLA-A2 Antigen / physiology
  • Humans
  • Lymphatic Metastasis
  • Lymphocytes, Tumor-Infiltrating / immunology
  • Melanoma / immunology*
  • Melanoma / pathology
  • Molecular Sequence Data
  • Multienzyme Complexes / metabolism*
  • Neoplasm Proteins / chemistry
  • Neoplasm Proteins / immunology*
  • Peptide Fragments / immunology*
  • Peptides / immunology
  • Proteasome Endopeptidase Complex
  • Repressor Proteins / chemistry
  • Repressor Proteins / immunology*
  • T-Lymphocytes, Cytotoxic / immunology*
  • Tumor Cells, Cultured


  • Antigens, Neoplasm
  • Epitopes, T-Lymphocyte
  • HLA-A2 Antigen
  • Multienzyme Complexes
  • Neoplasm Proteins
  • Peptide Fragments
  • Peptides
  • Repressor Proteins
  • SSX-2 peptide (41-49)
  • synovial sarcoma X breakpoint proteins
  • Cysteine Endopeptidases
  • Proteasome Endopeptidase Complex