Isolation of a retrovirus from two fish cell lines developed from chinook salmon (Oncorhynchus tshawytscha) with plasmacytoid leukaemia

Two new cell lines developed from chinook salmon with plasmacytoid leukaemia have been found to be producing a virus. The virus has been identified as a retrovirus based on: type of c.p.e. induced in culture; morphology and density of the particle; presence of Mn²⁺-dependent, poly(rA)-directed reverse transcriptase activity which was associated with a density of 1·16 to 1·18 g/ml in sucrose; electrophoretic pattern of the polypeptides from purified virions; elevated [³H]UTP labelling of RNA in the cell cultures occurring at a density of 1·16 to 1·18 g/ml in sucrose. This report describes the first isolation of a retrovirus from a salmonid cell line.