The specificity of Atlantic salmon antibodies made against the fish pathogen Vibrio salmonicida, establishing the surface protein VS-P1 as the dominating antigen.

The specificity of salmon (Salmo salar) antibodies made against the fish pathogen Vibrio salmonicida was studied. Salmon immunized with V. salmonicida emulisified in Freund's complete adjuvant produced antibodies which preferentially bound to a 40 KD outer surface molecule (VS-P1). Moreover, the bulk of the antibodies were specific for one particular epitope on VS-P1, defined by a mouse monoclonal antibody - as detected with a blocking ELISA. The data imply that salmon B cells mainly (90%) recognize one particular determinant on V. salmonicida and thus express a limited repertoire of antibody specificities against this pathogen.