Humoral immune response in Atlantic salmon, Salmo salar L., to cellular and extracellular antigens of Aeromonas salmonicida

Abstract. The putative virulence factors of Aeromonas salmonicida , the aetiological agent of furunculosis in salmonids, are candidates for protective antigens in effective vaeeines against furunculosis. In this report, the authors have compared the immunogenieily of eell-associated and extracellular antigens of A. salmonicida in Atlantic salmon, Salmo salar L., to that in rabbit. The animals were immunized with formalin-killed whole cells and formalin-inactivated extracellular products (ECP), either separately or in combination. The ability of the antigens to induce antibody production was studied by elisa and Western blotting techniques. These results confirm previous reports that far more structures are immunogenie in rabbit compared to the antibody responses elicited in salmon. However, in both species, some antigens were dominant, including a caseinolytic protease in addition to the A-protein and high and low MW LPS.