Preparation of rat monoclonal antibodies to epitopes encoded by the viral oncogene (v-fms) of McDonough feline sarcoma virus.

The McDonough strain of feline sarcoma virus (SM-FeSV) contains a viral oncogene, v-fms, transduced from cat cellular genetic sequences designated c-fms. Monoclonal antibodies reactive to antigenic determinants encoded by v-fms were prepared by immunizing rats with live, syngeneic SM-FeSV-transformed cells, and fusing splenic lymphocytes from a tumor-bearing animal with cultured rat myeloma cells. Culture supernatants from hybrids producing antibodies to epitopes encoded by v-fms were identified by immunoprecipitation of radiolabeled polypeptides from SM-FeSV-transformed mink cells. Four positive hybrids were cloned twice in soft agar, established as stable lines, and grown in defined serum-free medium to facilitate purification of homogeneous antibodies. The monoclonal antibodies were used to assay SM-FeSV-specific products by "immunoblotting" of electrophoretically separated proteins, and by fixed-cell immunofluorescence.