A newly identified MAGE-3-derived, HLA-A24-restricted peptide is naturally processed and presented as a CTL epitope on MAGE-3-expressing gastrointestinal cancer cells.
OBJECTIVE
In order to broaden the possibility for anti-MAGE-3 immune targeting, it is important to identify HLA-A24-restricted epitopes derived from MAGE-3, since HLA-A24 is one of the most common alleles in Japanese and Asian people. In the present study, we defined a new MAGE-3 derived, HLA-A24-binding peptide presented as a CTL epitope on gastrointestinal cancer cells.


METHODS
A panel of MAGE-3-derived peptides (9mer and 10mer) with the HLA-A24-binding motif was selected, and identification of MAGE-3-derived, HLA-A24-restricted CTL epitopes was performed by a reverse immunology approach. To induce MAGE-3-peptide specific CTLs, PBMCs were repeatedly stimulated with monocyte-derived, mature DCs pulsed with the peptides. Subsequent peptide-induced T cells were tested for their specificities by ELISPOT, tetramer and cytotoxic assay. CTL clones were then obtained from the CTL line by limiting dilution.


RESULTS
The peptide-inducing CTLs revealed that MAGE-3(113)-peptide was reacted as a CTL epitope in a HLA-A24-restricted fashion, confirmed by ELISPOT and cytotoxic assays. In addition, the MAGE-3(113)-specific CTL clones, confirmed by tetramer assay, showed that the MAGE-3(113) epitope is naturally processed and presented as the CTL epitope on MAGE-3-expressing gastrointestinal cancer cells by evaluating the cold target inhibition assays.


CONCLUSIONS
The newly identified MAGE-3(113)-peptide epitope is naturally processed and presented as the CTL epitope on MAGE-3-expressing gastrointestinal cancer cells, indicating that anti-MAGE-3 immune targeting with the MAGE-3(113) peptide is a promising approach for treatment.
Miyagawa
Naoto
N
First Department of Surgery, University of Yamanashi, Japan.
Kono
Koji
K
Mimura
Kousaku
K
Omata
Hideo
H
Sugai
Hidemitsu
H
Fujii
Hideki
H
D017951:Antigen Presentation; D000951:Antigens, Neoplasm / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D045744:Cell Line, Tumor; D018984:Epitopes, T-Lymphocyte; D015972:Gene Expression Regulation, Neoplastic; D015234:HLA-A Antigens / Q000378:metabolism*; D059871:HLA-A24 Antigen; D006801:Humans; D009363:Neoplasm Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000276:immunology / Q000378:metabolism*
D000951:Antigens, Neoplasm; D018984:Epitopes, T-Lymphocyte; D015234:HLA-A Antigens; D059871:HLA-A24 Antigen; C072013:MAGEA3 protein, human; D009363:Neoplasm Proteins