Further studies on the antigenic properties and distribution of the putative bovine leukemia virus

The C-type viruses found in long-term cultures. New Bolton Center (NBC) cell lines, of peripheral lymphocytes from leukemic cattle and in short-term cultures of bovine buffy coat(BC) cells share an immunofluorescent(IF)antigen detected in the cytoplasm of infected cells as well as an antigen demonstrable in gel diffusion experiments. Therefore the viruses from these cultures most likely represent different isolates of the putative bovine leukemia virus (BLV). The BLV precipitin antigen is analogous to the group specific (gs) antigens of the leukemia viruses of other species in that it is soluble, ether resistant, and apparently located within the virion. These observations, together with results showing that the specificity of the BLV precipitin antigen differs from that of the gs antigen of other mammalian leukemia viruses, indicate that the former antigen represents the intraspecies (gs-1) determinant of BLV. Antibodies to the precipitin viral antigen were found in 82% of cattle with leukemia and in 40% of clinically normal adult cattle in multiple-case herds. These groups of animals also had fluorescent antibodies to the virus, but with significantly higher frequencies (100% and 76%, respectively). On the other hand, in leukemia-free herds, precipitating antibodies were not found and the incidence of fluorescent antibodies was only 3%.