Soluble Fas-ligand (sFasL) in human astrocytoma cyst fluid is cytotoxic toT-cells: Another potential means of immune evasion

Gliomas of all grades have been shown to express FasL, an apoptosis-inducin g protein. Because of the ability of FasL to be cleaved from cell surfaces by metalloproteinases, soluble FasL can be released by FasL bearing cells i nto surrounding tissues. In the present study, we demonstrate the presence of sFasL in the cyst fluids of astrocytomas. Additionally, a human T-cell l ine, Jurkat, exposed to astrocytoma cyst fluid resulted in significantly in creased cytotoxicity as compared to controls, an effect blocked by FasL neu tralizing antibodies. This suggests that sFasL, may be utilized as a means of escaping immune surveillance by these tumors.