Cloned astrocytic and spongioblastic cells of virus-induced rat gliomas and spontaneous human gliomas will be studied immunochemically. Qualitative and quantitative analysis of the antigens present at the cell membranes and subcellularly will be analyzed by sequential adsorption analysis of purified radiolabelled antibodies on monolayer cultures and morphological localization of antigens with phase- immunofluorescence and electron microscopic localization of peroxidase- labelled antibodies. These studies are intended to shed light on glial antigenicity as a guide toward establishing tentative protocols for clinical investigation of human brain tumor immunotherapy.