Glia-specific antigen in the intracranial tumors. Immunofluorescence study

26 gliomas and 14 non-glial tumors were examined for the presence of nervous system specific antigen (CGSA) to assess the antigenic properties of neoplastic tissue in relation to histogenesis and degree of differentiation of tumors. Double layer immunofluorescence (IMF) technique was used for the cellular localization of the antigen. CGSA was found in the cytoplasm of normal, reactive and neoplastic neuroglial cells. Well differentiated astrocytomas showed the strongest IMF reactions and largest number of IMF-positive cells. Tumors with histological signs of anaplasia displayed foci of IMF-negative cells irregularly distributed in the sections. There were no completely negative astrocytomas owing to a marked affinity of the specific astisera to the astrocytic cell line. In the oligodendrogliomas a smaller amount of the antigen was found than in the astrocytomas. Histological evidence of malignancy in these tumors was accompanied by strikingly small number of positive cells and weaker IMF reactions as compared to the well differentiated oligodendrogliomas. Anaplastic gliomas showed only traces of CGSA and non-glial tumors were entirely negative. The results suggest a deficiency of normal antigenic material in the neoplastic glia, particularly of oligodendrogliomas and anaplastic gliomas.