Monoclonal antibodies to the v-fes product and to feline leukemia: Virus P27 interspecies-specific determinants encoded by feline sarcoma viruses

Monoclonal antibodies to p27 gag and v-fes specific determinants on the gag-onc polyprotein encoded by Snyder-Theilen feline sarcoma virus (ST-FeSV) were prepared. In order to obtain hybridoma clones specific to the antigenic determinants encoded by the FeSV genome, Lou rats were immunized with ST-FeSV-transformed, virus-nonproducing syngeneic cells, and boosted with either the same cells or affinity-purified feline leukemia virus (FeLV) p27. Three distinct clones reactive to both FeLV p27 and p85^gag-fes, and one clone specific for a p85 fes determinant were established. The anti-p27 monoclonal antibodies also reacted with the polyproteins p959^gag-fes and p839^gag-fgr from Gardner-Arnstein (GA) and Theilen-Pedersen (TP1) FeSV, respectively. The anti-p27 monoclonal antibodies reacted with MuLV p30 and RD114 p28 but not with RSV, MMTV, or BLV. These results indicated that the part of the p27 gag gene that is preserved in ST-, GA, and TPI-FeSV encodes interspecies-specific p27 determinants.