EFFICIENT INDUCTION OF ANTITUMOR CYTOXIC T-LYMPHOCYTES FROM A HEALTHYDONOR USING HLA-A2-RESTRICTED MAGE-3 PEPTIDE IN-VITRO

The antigenic peptides encoded by tumor-rejection antigen genes, MAGE- 1 and -3, have been identified, and various methods have been utilized for the in vitro induction of MAGE-specific, cytotoxic T lymphocytes (CTL) from peripheral blood mononuclear cells (PBMC) using synthetic p eptides. However, all of these methods are technically demanding and t hus have a relatively limited usefulness. We herein report a simple an d efficient method for the in vitro induction of specific CTL by using the HLA-A2-restricted MAGE-3 peptide from the PBMC of a healthy donor . CTL responses could thus be efficiently induced from unseparated PBM C by stimulation with freshly isolated, peptide-pulsed PBMC as antigen -presenting cells and by using interleukin-7 and keyhole limper hemocy anin for the primary culture. The induced CTL could thus recognize and lyse not only HLA-A2 target cells pulsed with the peptide but also HL A-A2 tumor cells expressing MAGE-3, in an HLA-class-I-restricted manne r. This simple method may, therefore, become a useful tool for investi gating the potential peptides for tumor antigens as well as for develo ping various immunotherapeutic approaches for human malignant tumors.