Proteasome-assisted identification of a SSX-2-derived epitope recognized by tumor-reactive CTL infiltrating metastatic melanoma.
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.
Ayyoub
Maha
M
Division of Clinical Onco-Immunology, Ludwig Institute for Cancer Research, University Hospital, Lausanne, Switzerland. Maha.Ayyoub@chuv.hospvd.ch
Stevanovic
Stefan
S
Sahin
Ugur
U
Guillaume
Philippe
P
Servis
Catherine
C
Rimoldi
Donata
D
Valmori
Danila
D
Romero
Pedro
P
Cerottini
Jean-Charles
JC
Rammensee
Hans-Georg
HG
Pfreundschuh
Michael
M
Speiser
Daniel
D
Lévy
Frédéric
F
D000595:Amino Acid Sequence; D000818:Animals; D000951:Antigens, Neoplasm / Q000737:chemistry / Q000276:immunology*; D019556:COS Cells; D002999:Clone Cells; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D003601:Cytotoxicity Tests, Immunologic; D018604:Epitope Mapping; D018984:Epitopes, T-Lymphocyte / Q000276:immunology*; D015789:HLA-A2 Antigen / Q000502:physiology; D006801:Humans; D008207:Lymphatic Metastasis; D016246:Lymphocytes, Tumor-Infiltrating / Q000276:immunology; D008545:Melanoma / Q000276:immunology* / Q000473:pathology; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000378:metabolism*; D009363:Neoplasm Proteins / Q000737:chemistry / Q000276:immunology*; D010446:Peptide Fragments / Q000276:immunology*; D010455:Peptides / Q000276:immunology; D046988:Proteasome Endopeptidase Complex; D012097:Repressor Proteins / Q000737:chemistry / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014407:Tumor Cells, Cultured
D000951:Antigens, Neoplasm; D018984:Epitopes, T-Lymphocyte; D015789:HLA-A2 Antigen; D009097:Multienzyme Complexes; D009363:Neoplasm Proteins; D010446:Peptide Fragments; D010455:Peptides; D012097:Repressor Proteins; C447821:SSX-2 peptide (41-49); C093962:synovial sarcoma X breakpoint proteins; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex