Glycosaminoglycans (GAG) are polyanionic compounds, usually bound covalently to a protein core. They are a prominent component of the cell surface and are implicated in cell-cell interaction. Human glioma cells in tissue culture produce a much greater amount of hyaluronic acid (HA) than normal glial cells and they are shedding it in the media. Also, certain glioma cell lines are forming a hyaluronidase-sensitive "protective' coat that impairs their ability to elicit allogeneic CTL response. We are using glucocorticoids (Dexamethasone) or dimethylsulfoxide (DMSO) to inhibit the biosynthesis of HA and other GAG in cultured glioma cells with the objective to make them more susceptible to immune response and/or chemotherapy. Since Dexamethasone can be administered to humans, such a modification may be useful in the management of patients with gliomas.