The influence of various chemicals on the surface structure and the antigenicity of syngeneic glioma cells.

Brain tumours were induced in inbred Fischer rats (F344) by methylnitrosourea. A pleomorphic glioma (78-219) was established in vitro and propagated as 78FR-G-219 permanent cell line. These cells were modified either by dimethylsulfate or by trinitrobenzene sulfonic acid. Antisera were raised against both native an chemically latered cells in syngeneic rats. The cytotoxicity of these sera was tested against the native glioma cell line as target, by means of the 14C-nicotinamide release. The methylated cells induced a complement--dependent humoral cytotoxicity in the range of that produced by native cells (20%); trinitrophenylation, however, resulted in a two-fold increased cytotoxic humoral immune response. Effects of chaotropic salts on methylated cell surface structure suggested a mode of action different from that of trinitrophenylation, which could be further substantiated by scanning electron microscopy. Furthermore, a new tool for the evaluation of cell surface structure, secondary ion mass spectrometry, was applied on our cell system. Significantly different ionized fragments were obtained from normal brain cells and glioma cells, respectively.