The objective of the proposed research is the isolation of astrocytoma-specific antigens by means of the production of tumor-specific antisera in partially "tolerant" animals. Research already done by the applicants indicates that antiserum to antigens present in biopsied astrocytomas may be produced by the immunization of rabbits made partially "tolerant" to normal human tissue (plasma and brain). Antisera produced in this fashion will be absorbed using insoluble immunoadsorbents until they no longer contain antibodies to normal human tissue as determined by counter-immunoelectrophoresis, hemagglutination, immunofluorescence, or cytotoxicity techniques. Using these absorbed antisera tumor tissue, sera, and spinal fluid from astrocytoma patients will be tested for the presence of astrocytoma-specific antigens by counter-immunoelectrophoresis, immunofluorescence and cytotoxicity methods. The tumor and organ specificites of any identified antigen(s) will be determined by testing the antisera against a panel of non-brain normal tissue and non-astrocytic malignant tissue. Using purified specific antisera, these astrocytoma-specific antigens will be isolated by immunoaffinity chromatography, ion-exchange and gel filtration column chromatography, and preparative gel electrophoresis. Presently, the diagnosis of human astrocytomas is insensitive and expensive, and often requires invasive techniques. However, early diagnosis is important for improved patient prognosis. The isolation of astrocytoma-specific antigens will make possible the development of sensitive, inexpensive assays which will aid in diagnosis and treatment, and will thereby improve the prognosis of patients with these malignancies.