Generation of specific antitumor reactivity by the stimulation of spleen cells from gastric cancer patients with MAGE-3 synthetic peptide

The induction of cytotoxic T lymphocytes (CTL) from peripheral blood mononu clear cells (PBMC) using MAGE peptide has been investigated in order to use MAGE antigens immunotherapeutically. We therefore developed a simplified m ethod for inducing peptide-specific CTL that kill tumor cells expressing MA GE from the PBMC of either healthy donors or even cancer patients. Since th e spleen is a major lymphoid organ, we used a simple method to examine the capacity of spleen cells to generate MAGE-specific CTL by in vitro stimulat ion with MAGE peptide in gastric cancer patients. The CTL responses could t hus be induced from unseparated spleen cells in HLA-A2 patients with gastri c carcinoma expressing MAGE-3 by stimulating these cells with autologous sp leen cells pulsed with HLA-A2-restricted MAGE-3 peptide as antigen-presenti ng cells and by using keyhole limpet hemocyanin and interleukin-7 for the p rimary culture. The induced CTL were thus able to lyse HLA-A2-positive carc inoma cells transfected with MAGE-3 and expressing MAGE-3, as well as the t arget cells pulsed with the peptide, in an; HLA-class-I or -A2-restricted m anner. Since MAGE-specific CTL could be induced from the spleen cells of ga stric cancer patients, the spleen appears to play are important role in eit her clinical tumor vaccination or the treatment of cancer patients by adopt ive immunotherapeutic approaches using the MAGE peptide.