Isolation and in vitro growth of glioma-infiltrating lymphocytes, and an analysis of their surface phenotypes.

The present investigation was conducted in order to examine the feasibility of isolating and growing glioma-infiltrating lymphocytes in vitro as possible effector cells for use in new adoptive immunotherapy. Eight surgical specimens obtained from patients with malignant astrocytomas were treated by enzyme dispersion; the cells were separated on a density gradient and grown in the presence of human recombinant interleukin-2. The cultured lymphocytes were tested for cell-surface markers by using monoclonal antibodies in a flow cytometric analysis. In all cases the glioma-derived lymphocytes were grown in culture for several weeks with substantial increases in cell numbers (at least 5 X 10(8) cells). The mature T cell population (CD3, 89%) was found to have an increased proportion of the cytotoxic/suppressor phenotype CD8 (55%) as compared to peripheral blood lymphocytes (PBL's). Eighty-six percent of the cultivated lymphocytes expressed HLA-DR. The IL-2 receptor was predominantly expressed on the helper subset (CD4-positive). Otherwise, anti-CD16, which specifically reacts with natural killer (NK) cells, did not stain significantly more of the cultured gliomaderived lymphocytes compared with lymphocyte-activated PBL's. These results corroborate the observations made with conventional immunohistochemical examination. It has been demonstrated that T lymphocytes isolated from human cancers are enriched for specific reactivity to their autochthonous tumor cells. These experiments support the possible use of glioma-infiltrating lymphocytes as a new treatment for patients with malignant glioma.