Monoclonal antibodies reactive with glioma cell lines derived from experimental brain tumors.

The production of hybridomas between X63-Ag8.653 myeloma cells and spleen cells from female BALB/c mice immunized with 79FR-G-41 glioma cells is reported. One hundred and six hybridoma clones were obtained secreting monoclonal antibodies (McAbs) against different target cells. Specificity tests (RIA, micro-ELISA) showed that McAbs produced by three hybridoma clones (13GC1, 14BC1, 14FC3) bound 79FR-G-41 glioma cells but did not react with fibroblasts, kidney and brain cells of newborn F344 rats. From the specificity analysis of two McAbs (13GC1, 14BC1) it is evident that these did not only react with 79FR-G-41 cells but also with other glioma cell lines (78FR-G-219, 78FR-G-284, 78FR-G-299 and 78FR-G-344) established from chemically induced rat brain gliomas. These results suggest, in accordance with the findings in human neuroectodermal tumors, the expression of common reactivity antigens in different brain tumors of glial origin. However, the McAbs obtained against experimental rat glioma cells did not recognize glioma cells derived from spontaneous brain tumors of dog or man. Immunofluorescence and immunoperoxidase tests indicate that there is a remarkable heterogeneity among cells of experimental glioma lines with respect to the expression of glioma associated determinants recognized by McAbs. The fact that only a variable number instead of the totality of tumor cells in any asynchronous and uncloned tumor cell population expresses, at a certain time, recognizable antigenic determinants has to be taken into account, particularly if they are considered to be employing McAbs as carrier molecules for diagnostic and therapeutic purposes.