title: Immunoprecipitation of a Mr 64,000 glial tumor-associated antigen by monoclonal antibody 217c.
abstract: Monoclonal antibody 217c binds to a tumor-associated surface antigen of transformed rat glial cells. Treatment of C6 glioma cells with 2.5% 1-butanol yielded an extract which was active in competitive inhibition of antibody 217c to cell monolayers in an 125l-protein A assay as well as in binding antibody 217c in an enzyme-linked immunodot assay. The antigen, however, was not released in soluble form, but in a particulate fraction which could be pelleted by ultracentrifugation for 2 h at 120,000 X g. Antibody binding activity in the immunodot assay could be destroyed by heating the extract to 100 degrees C for 10 min. To determine the molecular weight of the antigenic polypeptide, cell monolayer cultures were surface radioiodinated and extracted with Nonidet P-40. Immobilized antibody 217c bound only a single labeled polypeptide with a molecular weight of 64,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. This surface peptide was present in the C6 glioma line as well as in oligodendrocyte and astrocyte cultures transformed either spontaneously or using ethylnitrosourea. It was absent from normal astrocyte and oligodendrocyte cultures of neonatal rat brain. In the glial lines studied the P-64 peptide appears as a surface marker indicating malignant transformation.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000912:Antibodies, Neoplasm / Q000276:immunology; D000951:Antigens, Neoplasm / Q000276:immunology / Q000302:isolation & purification*; D000440:Butanols; D011232:Chemical Precipitation; D008970:Molecular Weight; D009457:Neuroglia / Q000276:immunology*; D051381:Rats
chemical_list: D000911:Antibodies, Monoclonal; D000912:Antibodies, Neoplasm; D000951:Antigens, Neoplasm; D000440:Butanols