Antigenic heterogeneity of human brain tumors defined by monoclonal antibodies

The antigenic profiles of human gliomas and in vitro established cell lines were investigated using the monoclonal antibodies (MABs) MUC 8-22 and MUC 2-63. The reactivity with tissue samples and cytospin preparations obtained from 45 brain tumors was estimated by the indirect immunoperoxidase technique. In addition, computer-assisted cytofluorometry was used to quantify the intensity and distribution of antibody-binding. Various degrees of antibody-binding among and within gliomas and glioma-derived cell lines were observed. The data show that a variable percentage of cells are not labeled with the employed MABs. The spectrum of reactivity of the selected antibodies was independent of the histological grading of gliomas. However, there were significant differences in various stages of subcultivation of glioma lines. In most cases, the heterogeneity of antigen expression decreased during successive in vitro propagation of glioma cells. The extent of variation in staining intensity values differed within cell populations and reflected the antigenic heterogeneity of human brain tumors. The findings presented here suggest that the use of MABs which recognize glioma-associated antigens facilitates the objective analysis of brain tumors and is of potential value for immunohistochemical application in surgical neuropathology.