Serologic analysis of nitrosourea-induced rat gliomas.

Inbred CDF rats (cesarean-delivered F344 rats) were immunized with either a nitrosourea-induced glioma EA-285 or its subline EA-285A and both with and without Corynebacterium parvum. A humoral immune response in syngeneic rats to the immunizing tumor was demonstrated with micromodifications of different rosette assays (immune adherence assay, protein-A assay, and anti-C3-mixed hemadsorption assay). Extensive absorption studies of two immune sera with the highest reactivity revealed two glioma-specific antigens (or two components of one antigen) on the cell surface of the cloned tumor subline. One antigen was present only on the cell surface of the subline of the glioma used for both immunization and absorption analyses. The other antigen appeared on the cell surface of both the cloned subline EA-285A and the parental cell line EA-285. These preliminary studies showed that CDF rats immunized against a syngeneic glioma mounted a humoral immune response that appeared to be individually tumor-specific.