Identification of HLA-A2-restricted CTL epitope encoded by the MAGE-n gene of human hepatocellular carcinoma.
BACKGROUND
Identification of the cytotoxic T lymphocytes (CTL) restricted epitopes of tumor antigens opens up possibilities of developing a new cancer vaccine. For the MAGE-n has been demonstrated closely associated with hepatocellular carcinoma (HCC) and HLA-A2.1 is found in over 50% of HCC patients in China, we aim at identifying MAGE-n-encoded peptide presented by HLA-A2.1.


METHODS
A HLA-A2.1-restricted CTL epitope was identified by using an improved "reverse immunology" strategy: (a) computer-based epitope prediction from the amino acid sequence of MAGE-n antigen; (b) peptide-binding assay to determine the affinity of the predicted peptide with HLA-A2.1 molecule; (c) stimulation of primary T-cell response against the predicted peptides in vitro; and (d) testing of the induced CTLs toward HCC cells expressing MAGE-n antigen and HLA-A2.1.


RESULTS
Of the five tested peptides, effectors induced by a peptide of MAGE-n at residue position 159-167(QLVFGIEVV) lysed HCC cells expressing both MAGE-n and HLA-A2.1. Our results indicated that peptide QLVFGIEVV was a new HLA-A2.1-restricted CTL epitope capable of inducing MAGE-n specific CTLs in vitro.


CONCLUSIONS
Identification of the MAGE-n /HLA-A2.1 peptide QLVFGIEVV may facilitate peptide-based specific immunotherapy for HCC. The combination of epitope prediction, epitope reconstruction method and immunological methods can improve the efficiency and accuracy of CTL epitope studies.
Dong
Hai-Long
HL
Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China.
Li
Zeng-Shan
ZS
Ye
Jing
J
Qu
Ping
P
Huang
Ya-Yu
YY
Wu
Wen
W
Lu
Shao-Ying
SY
Chen
Guang-Sheng
GS
Sui
Yan-Fang
YF
D000595:Amino Acid Sequence; D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000473:pathology; D000939:Epitopes; D005544:Forecasting; D015789:HLA-A2 Antigen / Q000235:genetics* / Q000276:immunology*; D006801:Humans; D007167:Immunotherapy / Q000379:methods; D008113:Liver Neoplasms / Q000235:genetics* / Q000473:pathology; D008969:Molecular Sequence Data; D009363:Neoplasm Proteins / Q000235:genetics*; D013602:T-Lymphocytes, Cytotoxic
D000951:Antigens, Neoplasm; D019496:Cancer Vaccines; D000939:Epitopes; D015789:HLA-A2 Antigen; C095203:MAGEA6 protein, human; D009363:Neoplasm Proteins