[Isolation and expansion of glioma-infiltrating lymphocytes in vitro: an analysis of their surface phenotypes and antitumor activities].

The present study was conducted in order to examine the feasibility of isolating and growing glioma-infiltrating lymphocytes in vitro as possible effector cells for use in an adoptive immunotherapy. Thirty surgical specimens obtained from patients with malignant astrocytomas were studied. The glioma-infiltrating lymphocytes were separated from tumor tissue, expanded in the presence of interleukin-2, and evaluated their anti-tumor activities in vitro. Eighteen of 30 cultures of glioma-derived lymphocytes expanded with a substantial increase in cell numbers, of at least 5 x 10(8) cells up to 5 x 10(9), 4 to 8 weeks after the initiation of culture. The expanding glioma-derived lymphocytes consisted of 88 +/- 10% CD3+ T cells including both CD4+ and CD8+ subpopulations. CD16 was expressed on 4 +/- 5% of the cells and three cultures studied exhibited 14% +/- 1 of CD56+ cells. After 4 to 8 weeks of the proliferation period, the lymphocytes ceased to grow in all cultures. The glioma-derived effector lymphocytes could lyse almost all the autologous tumor targets as well as allogeneic glioma cells. The cytotoxic activity of the glioma-derived lymphocytes appeared to be similar or inferior to that of interleukin-2-activated peripheral blood lymphocytes obtained from the same patients in killing autologous glioma cells. The glioma-derived effector cells could also lyse three-dimensional glioma targets (spheroids), but this lytis activity was clearly lower than that of the activated peripheral blood lymphocytes. Ability of these effector cells to infiltrate glioma tissue was doubtful, since after 24-hours coculture of effector cells with target spheroids, the effector cells scarcely infiltrated the spheroids. In summary, glioma-derived lymphocytes expanded in bulk culture with interleukin-2 consisted predominantly of T-lymphoblasts with the ability to kill autologous glioma cells and also to lyse glioma spheroids. However a benefit of use of the glioma-derived lymphocyte as a novel effector cells in clinical trail replacing the IL-2-activated peripheral blood lymphocytes could not be found.