Detection of bovine leukemia virus in tissue cultures

Syncytium formation was demonstrated in cocultivation of cow and sheep embryo kidney cells with peripheral blood lymphocytes from leukemic cattle. The beginning of this phenomenon was observed at 3--4, and maximum development at 6--8 days of cocultivation. Lymphocytes of 22 out of 24 leukemic animals were capable of inducing syncytium formation. Parallel examinations of cocultivated cells by the direct immunofluorescence procedure using fluorescent antibodies from sera of leukemic cows gave positive results in 23 our of 24 cases, whereas lymphocytes of 12 normal cows never induced either syncytium or specific antigens.