Vibrioantigens of polyvalent vaccines enhance the humoral immune response toAeromonas salmonicidaantigens in Atlantic salmon (Salmo salarL.)

Seven experimental oil-adjuvanted vaccines containingAeromonas salmonicidaand one or more of the following components:Vibrio salmonicida,Vibrio anguillarumserovar O1 andV. anguillarumserovar O2, were compared to a monovalentA. salmonicidavaccine regarding their ability to induce antibody production againstA. salmonicidain Atlantic salmon. Enzyme-linked immunosorbent assay (ELISA) tests were used to measure the humoral immune response against various antigen preparations fromA. salmonicida; bacterial cell-sonicate, A-layer protein and lipopolysaccharide. The effects of the differentVibriospp. on the generation of specific antibodies were estimated through a factorial statistical design. The results showed that stronger humoral immune responses toA. salmonicidaantigens were induced in fish vaccinated with the various polyvalent vaccines, compared to fish vaccinated with the monovalent furunculosis vaccine.V. salmonicidatended to be the most important component for this enhancement, althoughV. anguillarumalso contributed. Immunological cross-reactions betweenA. salmonicidaandV. salmonicidais a possible mechanism.