Induction of specific cytotoxic T lymphocytes against autologous brain tumor by crossreactive 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 effective for antigen stimulation for CTL induction in place of autologous glioblastoma cells, which are difficult to expand in culture. The optimal ratio between nylon wool-passed T lymphocytes and nylon wool-adherent accessory cells to induce CTL in the patient's PBL was found to be 25 to 1. In vitro-activated CTLs induced by MM2 were cytotoxic not 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 cross-reactive allogeneic tumor cells as the stimulator could be clinically valuable to treat malignant brain tumors.