Effects of antigens from Aeromonas salmonicida ssp.achromogenes on leukocytes from primed and unprimed Atlantic salmon (Salmo salar L.)

The effects of extracellular antigens isolated from Aeromonas salmonicida ssp.achromogenes, were tested on leukocyte cultures from the head-kidney of Atlantic salmon (Salmo salar L.) fingerlings. Samples from vaccinated fingerlings were compared to samples from control fingerlings that were injected with incomplete Freunds adjuvant (IFA) or phosphate buffered saline (PBS). The antigen preparations used for the comparative studies were extracellular products (ECP) and a 20 kDa toxic metallo-caseinase (AsaP1). Lipopolysaccharide (LPS) isolated from the bacterium was tested on unvaccinated fingerlings only. All antigen preparations were mitogenic to cultures from unvaccinated fish. In cultures from vaccinated fish there were difficulties in discerning between mitogenic effects, adjuvant induced cell activation and possible specific responses to the antigens.