Interleukin-2 induces the growth of human glioblastoma cells in culture

The ability of the T cell growth factor interleukin-2 (IL-2) to support the proliferation of human glioblastoma cells in short-term cultures was evaluated. A morphological, cytochemical and immunocytochemical analysis was carried out at different times of treatment. In the presence of IL-2 growth of tumor cells was observed. On the contrary, in the absence of IL-2 only few colonies derived from tumor fragments were obtained and these were so after a long time. The immunocytochemical study revealed that IL-2 induces the expression of the IL-2 receptor on human glioblastoma cells. In the presence of IL-2 proliferation of infiltrating lymphoid cells inside the tumor fragments was also observed. Morphological and cytochemical analysis of these cells revealed positivity for acid phosphatase (AP), dihydrofolate reductase (DHFR), dipeptydilaminopeptidase (DAP IV) and negativity for serine esterase. These data are in agreement with our previous study on activated lymphoid subsets. On the other hand, an absence of infiltrating lymphocytes was observed in cultures without IL-2. These results indicate that local treatment of human glioblastoma using IL-2 might produce tumor cell proliferation.