Derivation of a brain tumor-selective monoclonal antibody from hybridoma between mouse myeloma and rat spleen cells immune to syngeneic glioma.

Fischer 344 (F344) rats hyperimmunized with syngeneic 9L/R3 glioma cells produced antibody selective to glioma cells. Hybridomas prepared from the spleen cells of the immunized rat were cloned, and we obtained a hybridoma clone which produced monoclonal IgM antibody, termed FR77, that showed selectivity to glioma cells. Immunoperoxidase staining of cultured cells revealed that FR77 was reactive with 3 lines of rat glioma cells but not with normal F344 rat fibroblasts. Immunohistochemical staining of F344 rat tissue sections with biotinylated FR77 demonstrated that FR77 could bind with glioma tissue developed by intracerebral injection of 9L/R3 glioma cells but not to normal parts of the brain tissues and other normal tissues tested. The FR77-defined antigen was observed to be mainly localized in cytoplasm of glioma cells but a small portion of the antigen was also detected on the glioma cell surface.