VARIABLE EXPRESSION ON LUNG-CANCER CELL-LINES OF HLA-A2-BINDING MAGE-3 PEPTIDE RECOGNIZED BY CYTOTOXIC T-LYMPHOCYTES

Cytotoxic T lymphocytes (CTL) specific for HLA-A2-binding MAGE-3 pepti de (FLWGPRALV) were generated by repetitive stimulation of PBMC with t he peptide in the presence of EBV-transformed B blasts and IL-2. Using these CTL, we investigated the expression of the HLA-A2-binding MAGE- 3 peptide on lung cancer cell lines. Of 14 cell lines investigated, 1- 87, PC-9, OU-LC-KI, 11-18 and LK87 were derived from HLA-A2 positive p atients. But cytofluorometry analysis showed that 1-87, PC-9 and OU-LC -KI, but not 11-18 or LK87 expressed the HLA-A2 antigen. All five cell lines expressed MAGE-3 gene mRNA. Twelve of thirteen CTL lines from t wo HLA-A2 positive donors showed no cytotoxicity against any of the 14 lung cancer cell lines. CTL line TI-1 showed cytotoxicity against 1-8 7 but not against any of the other cell lines. Treatment of 1-87 with IFN-gamma greatly augmented the cytotoxicity of TI-1 and induced it in the other 12 CTL lines, confirming the expression of the peptide on 1 -87. No cytotoxicity was induced by IFN- gamma treatment of PC-9 or OU -LC-KI. However, PC-9 and OU-LC-KI pulsed with the peptide were killed efficiently by all of the CTL lines, suggesting no expression of the peptide on those cells. A low level of cytotoxicity was induced on 11- 18 but not LK87 by IFN-gamma treatment, although expression of the HLA -A2 antigen was not observed by cytofluorometry. These findings showed that expression of the HLA-A2-binding MAGE-3 peptide recognized by CT L was variable on lung cancer cell lines.