The anti-tumor immune response induced by a combination of MAGE-3/MAGE-n-derived peptides.

Tumor antigen-derived peptides have been widely used to elicit tumor-specific cytotoxic T lymphocytes (CTLs). MAGE gene products are of particular interest owing to their wide expression in many tumors and their potential to induce tumor-specific CTL responses. Antigen-specific CTLs induced by MAGE gene-derived peptides have proven to be highly efficacious in the prevention and treatment of various types of tumors. MAGE-3 has been used as a target for tumor immunotherapy. MAGE-n is a new member of the MAGE gene family and has been shown to be closely associated with hepatocellular carcinoma (HCC). However, the majority of previous investigations focused on the single MAGE antigen-derived peptides as a cancer vaccine which has many limitations. The tumor antigen expression is known to be heterogeneous and tumor cells can express multiple tumor antigens. Thus, vaccines incorporating single antigen-derived epitopes may be inadequate in generating a complete immune response against the tumor. Instead, a polyvalent vaccine incorporating epitopes derived from several tumor antigens may be more effective. Our study combined the MAGE-3 and MAGE-n-derived peptides as a cancer vaccine. The results showed that the combination of MAGE-3 and MAGE-n epitopes induced more effective anti-tumor immune responses than either of the peptides alone. In addition, the peptide-specific activity was observed to be in an MHC-restricted manner. Our study indicated that the combination of several tumor antigen-derived peptides may present a better peptide-based cancer immunotherapy.