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.
Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, People's Republic of China.
Hai-Long
HL
Dong
Zeng-Shan
ZS
Li
Jing
J
Ye
Ping
P
Qu
Ya-Yu
YY
Huang
Wen
W
Wu
Shao-Ying
SY
Lu
Guang-Sheng
GS
Chen
Yan-Fang
YF
Sui
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