INDUCTION OF SPECIFIC CYTOTOXIC T-LYMPHOCYTES AGAINST AUTOLOGOUS BRAIN-TUMOR BY CROSS-REACTIVE ALLO-TUMOR CELL STIMULATION

Cytotoxic T lymphocytes (CTL) against autologous malignant brain tumor were generated in peripheral blood lymphoid cells (PBL) prepared from a patient with a malignant brain tumor by stimulation of the cultured PBL for 7 days with attenuated crossreactive malignant melanoma (MM2) cells pretreated with mitomycin C. The crossreactive MM2 cells were e ffective for antigen stimulation for CTL induction in place of autolog ous glioblastoma cells, which are difficult to expand in culture. The optimal ratio between nylon wool-passed T lymphocytes and nylon wool-a dherent accessory cells to induce CTL in the patient's PBL was found t o be 25 to 1. In vitro-activated CTLs induced by MM2 were cytotoxic no t only to MM2, but also to the autologous tumor cells in an HLA class I-restricted manner, and their surface phenotype was found to be CD3() and CD8(+). CTL therapy using crossreactive allogeneic tumor cells a s the stimulator could be clinically valuable to treat malignant brain tumors.