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MAGE-A antigens belong to cancer/testis (CT) antigens that are expressed in tumors but not in normal tissues with the exception of testis and placenta. Among MAGE-A antigens, MAGE-A10 is extensively expressed in various histological types of tumors, representing an attractive target for tumor immunotherapy. Cytotoxic T lymphocytes (CTLs) play a key role in anti-tumor immune responses, so the identification of CTL epitopes derived from MAGE-A10 would contribute a lot to the design of epitope-based vaccines for tumor patients. In this study, we predicted HLA-A*0201-restricted CTL epitope peptides of MAGE-A10, followed by peptide/HLA-A*0201 binding affinity and complex stability assays, and induced peptide-specific CTL immune responses. Of the selected three peptides (designated P1, P2 and P3), P1 (MAGE-A10310-318, SLLKFLAKV) could elicit peptide-specific CTLs both in vitro from HLA-A*0201-positive PBMCs and in HLA-A*0201/Kb transgenic mice. And, the induced CTLs could lyse MAGE-A10-expressing tumor cells in a HLA-A*0201-restricted fashion but not MAGE-A10-negative tumor cells. Our results demonstrate that the peptide MAGE-A10310-318 is a HLA-A*0201-restricted CTL epitope of MAGE-A10 and could serve as a target for therapeutic antitumoral vaccination.

MAGE-A antigens belong to cancer/testis (CT) antigens that are expressed in tumors but not in normal tissues except testis and placenta. MAGE-A antigens and their epitope peptides have been used in tumor immunotherapy trials. MAGE-A4 antigen is extensively expressed in various histological types of tumors, so it represents an attractive target for tumor immunotherapy. In this study, we predicted HLA-A*0201-restricted cytotoxic T lymphocyte (CTL) epitopes of MAGE-A4, followed by peptide/HLA-A*0201 affinity and complex stability assays. Of selected four peptides (designated P1, P2, P3, and P4), P1 (MAGE-A4(286-294), KVLEHVVRV) and P3 (MAGE-A4(272-280), FLWGPRALA) could elicit peptide-specific CTLs both in vitro from HLA-A*0201-positive PBMCs and in HLA-A*0201/K(b) transgenic mice. And the induced CTLs could lyse target cells in an HLA-A*0201-restricted fashion, demonstrating that the two peptides are HLA-A*0201-restricted CTL epitopes and could serve as targets for therapeutic antitumoral vaccination.

To study the influence of different solvent systems on the isomers of melanoma antigen-encoding gene-2(MAGE-2) epitope peptide synthesized by Marrifield's solid synthesis method, MAGE-2(171-179) epitope peptides were pre-treated using ethanol and methanol systems respectively, and then analysed by RP-HPLC/MS, with dimethyl-sulphoxide (DMSO) as control solvent. Results demonstrated that 100% ethanol and 100% methanol solvents could induce the production of isomers of MAGE-2, while 100% DMSO, 50% ethanol and 50% methanol could not. These isomeric peptides could be reversed greatly if treated with trifluoroacetic acid (TFA). The results also showed that the analysis would be distorted and the yield of peptides would decrease dramatically if the peptides were pre-treated with high concentrations of ethanol and methanol before RP-HPLC analysis and preparation. Thus it is suggested that it might be better to decrease the concentration of organic phase in the solvent system for the resolvable hydrophobic peptides, acidified ethanol and methanol might also be better for the highly hydrophobic peptides, and DMSO would be a good solvent for hydrophobic peptides analysis provided that it would not influence the resolving power of chromatography.