Two separate membrane-bound antigens on human glioma cells in tissue culture detected with sera from glioma patients by immunofluorescence.

Sera from patients with malignant and benign gliomas, as well as sera from healthy donors, were tested by indirect immunofluorescence to detect antibodies against antigens on the membrane of glioblastoma, astrocytoma, reactive perimetastatic glia, normal glia and fibroblasts in tissue culture. Sera from glioblastoma patients reacted with glioblastoma, astrocytoma and reactive glial cells; they were negative on normal glia and on fibroblasts, whereas sera from astrocytoma patients were unreactive. Sera from control patients were positive in 7 out of 15 cases, although some differences were noted in the pattern of reaction. Absorption with astrocytoma powder, with glioblastoma and reactive glial cells indicated that all the positive cell lines expressed an astrocytoma-associated antigen "A", while only glioblastoma lines and reactive glial line shared a supplementary antigen "G". Neither of these 2 antigens seemed to be present in significant amount in normal brain, since the positive reactions could not be abolished by absorption with normal brain powder. The relationship between these 2 antigens and the process of increasing malignancy in gliomas is briefly discussed.