Biochemical and histologic evidence of plasmacytoid leukemia and salmon leukemia virus (SLV) in wild-caught chinook salmon Oncorhynchus tshawytscha from British Columbia expressing plasmacytoid leukemia

Seven of 118 wild-caught chinook salmon Oncorhynchus tshawytscha had histologic signs of plasmacytoid leukemia (PL). A pooled tissue sample from 2 of these PLpositive f ~ s h was examined and found to be Infected with a retrovirus as ~ndicated by the elevated reverse transcnptase activity associated with a density of 1.17 g cm-3 in sucrose and polypeptides with identical electrophoretic mobilities to those of the purified salmon leukemia virus (SLV). The virus from the wild-caught chinook salmon was serologically identical to SLV, as anti-SLV hyperimmune rabbit antisera reacted with the 82, 43, and 27 kDa polypeptides of both purified SLV and the wild-caught chinook salmon. Thus, it appears that SLV-associated PL occurs, a t least a t a low level, in wildcaught chinook salmon.