Studies on bovine lymphosarcoma: formation of syncytia and detection of virus particles in mixed-cell cultures.

Abstract

AbstractThis paper reports studies on mixed‐cell cultures of human diploid embryonic lung (WI‐38) cells, embryonic bovine tracheal (EBTr) cells, and bovine embryonic kidney (BEK) cells with thoracic duct lymphocytes and buffy coat cells from lymphosarcoma and normal cattle, and lymphocytes from lymphosarcoma cattle that have been established as cell lines (NBC) in suspension culture. Peripolesis and emperipolesis were very pronounced during the first hours after initiation of mixed cultures with „lymphosarcoma”︁ lymphocytes, whereas little or no peripolesis or emperipolesis characterized mixed cultures with „normal”︁ lymphocytes. Syncytial formation, cytoplasmic vacuolation, and nuclear abnormalities occurred in all the mixed cultures containing cells from lymphosarcoma animals. Cells from normal animals did not provoke the characteristic cytopathic effect, with the exception of buffy coat cells from one animal. Interferon was demonstrated in some of the syncytia‐positive cultures. The data suggest that the cultures were infected with a latent syncytial virus. Immunological data indicate that this virus was not infectious bovine rhinotracheitis, bovine parainfluenza 3, or bovine viral diarrhea, and preliminary serological data suggest that the lymphosarcoma animals may develop neutralizing antibodies against it. In two cell lines derived from mixed cultures of WI‐38 and EBTr with NBC‐17, numerous virus particles were observed by electron microscopy both extracellularly and, in many instances, budding from the plasma membranes or from cytoplasmic vacuole membranes. The possible relationship of the virus to bovine lymphosarcoma remains to be elucidated.