Humoral immune response in glioma patients: A solubilized glioma-associated membrane antigen as a tool for detecting circulating antibodies.

Plasma membranes from normal and neoplastic human brain tissue were isolated and compared morphologically, biochemically and immunologically. There ultrastructure was identical, electrophoresis on polyacrylamide gel revealed at least 24 protein components, four of which were absent from membranes of normal tissue, whereas one was missing in the tumor pattern. The tumor-associated components could be solubilized by the non-ionic detergent Triton-X100 and were used as an antigen source for the immunological characterization of glioma membranes. By means of a rabbit antiserum immunologically identical components could be detected in the Triton extract of the membranes from all the 20 human gliomas tested so far, but not in normal or fetal brain, nor in liver, kidney or spleen tissue. These data indicate that the solubilized membrane components contain common glioma-associated membrane antigens which might be used in the detection of circulating antibodies in the sera of glioma patients. Of the 24 samples of sera tested so far, 19 (79%) contained precipitating antibodies against these membrane components as revealed by countercurrent electrophoresis.