Immature sockeye salmon (Oncorhynchus nerka) responded to the intraperitoneal injection of heat-killed, adjuvant-suspended cells of the kidney disease bacterium by producing agglutinins specific for the pathogen. These antibodies were detectable for at least 16 months following a single injection. With water temperatures of 12-15°C which prevailed during the first 100 days following this injection, the response was rather slow to develop, and whether or not antibodies were produced in this period depended on the dose of antigen given. Under a similar temperature regime, a second injection, given 13 months after the first, elicited a clear-cut anamnestic response. Ninety days following primary and secondary vaccination, maximum titres were 1:2,560 and 1:10,240, respectively.

The antibodies were electrophoretically isolated, studied, and are discussed.