COMPARATIVE-ANALYSIS OF A MONOCLONAL-ANTIBODY-BASED IMMUNOFLUORESCENCE TEST FOR PLASMACYTOID LEUKEMIA IN CHINOOK SALMON ONCORHYNCHUS-TSHAWYTSCHA

Plasmacytoid leukemia (PL) is a lymphoproliferative disorder that affe cts netpen-reared chinook salmon Oncorhynchus tshawytscha in British C olumbia, Canada. The only diagnostic test for PL is histologic evaluat ion of suspect fish. Monoclonal antibodies (MAbs) previously reported to react with tissues of PL-affected fish were used in a quantitative indirect fluorescence antibody (IFA) test. These MAbs reacted with a 7 5 kDa antigen that is highly expressed in tissues of fish with PL. Usi ng experimentally infected fish, the sensitivity, specificity, and pre dictive values of the IFA test were compared to those of the standard histologic test. The IFA test was determined to have a sensitivity of 72 %, which was significantly higher than that of histologic examinati on, and could detect experimental infection at 3 wk post-injection, ea rlier than histologic examination. The sensitivity and practicality of the IFA test will enable it to be a useful screening test for the det ection of PL.