Histocompatibility antigens on astrocytoma cells

Prostaglandin E2 as an immunomodulating factor released in vitro by human glioma cells

Cultured human glioma cells were found to produce soluble factors that can modulate the in vitro proliferative response of purified T lymphocytes stimulated by phytohemagglutinin (PHA). Neoplastic tissue was removed during surgery for brain glial tumors and cultured in vitro. The glial nature of the neoplastic cells was verified by means of anti-glial fibrillary acidic protein immunohistochemical staining. Serum-free supernatants from these cultures proved capable of suppressing in vitro proliferation of PHA-stimulated T lymphocytes. Suppression was reduced when indomethacin or aspirin was added to the culture medium. Thin-layer chromatography revealed the presence of prostaglandins and other arachidonic acid derivatives in the supernatants. The radioimmunoassay used to quantify the prostaglandin E2 (PGE2) in the supernatants showed detectable amounts of PGE2, which disappeared after the cultures had been treated with anti-inflammatory drugs. These data support the hypothesis that tumoral glial cells can play a role in the host immune response in the central nervous system, namely by producing soluble factors.

Endothelial growth factor production in cultures of human glioma cells

Human glioma cells derived from biopsied material were grown in tissue culture for periods of up to 2 weeks. Supernatants from these cultures were harvested at various intervals and their ability to enhance proliferation of cultured umbilical vein human endothelial cells was assessed. All of the supernatants tested contained some degree of endothelial cell mitogenic factor activity. The activity in the supernatants reached a maximum from cultures which were 4-8 days old and gradually decreased thereafter. Supernatants from the fibroblast monolayer were not significantly stimulatory for this endothelial cell model. On the other hand, supernatants from the glioma cultures did not increase the growth of human skin fibroblast or peripheral blood lymphocytes in culture. Extracts from bovine cartilage inhibited the mitogenic activity of the supernatants from glioma cultures.