Tumor specific fluorescent and complement-dependent cytotoxic antibodies in the serum of rats with chemically induced brain gliomas.

Brain tumors were induced in Sprague-Dawley and Long-Evans rats by administration of N-methyl-N-nitrosourea in the drinking water. Of these tumors, a grade 2 mixed glioma, a grade 2 to 3 astrocytoma and a grade 1 to 2 oligodendroglioma were established in vitro, maintained in culture and designated 75SD-G-376, 75SD-G-420 and 77LE-G-180, respectively. Of these mass cultures, two were successfully cloned and are currently available as 75SD-G-376C and 75SD-G-420C cell lines. Clonal lines produce S-100 protein and grow as tumors when isografted in young rats. Using the cultured cells as target cells , specific antibodies were searched for in the sera of the rats with the primary tumors by means of an indirect fluorescent antibody staining method and a complement-dependent antibody-mediated microcytotoxicity assay. Fluorescent and cytotoxic antibodies were demonstrated in the sera of the mixed glioma- and astrocytoma-bearing animals. However, a variable proportion of cells of the 75SD-G-376 and 75SD-G-420 lines showed no reaction with the corresponding sera. Furthermore, cytotoxic antibodies had a lytic effect on the autologous glioma cells only in the presence of rabbit complement.