Antigenic characterization of the etiological agent of the brown ring disease affecting manila clams

Vibrio P1 is considered as the causative agent of Brown Ring Disease, an epizootic disease of cultured clams in Europe. Although its pathogenic implication has been clearly established, its taxonomical inclusion and virulence mechanisms are not still completely elucidated. In the present work, we have studied the outer membrane protein (OMP) and lipopolysaccharide (LPS) patterns and other antigenic characteristics of Vibrio P1 strains, and we have compared to those both reference strains of Vibrio and Vibrio strains isolated from diseased clams, by means of SDS-PAGE, immunoblotting, Western blot, slide agglutination and dot-blot techniques. The present results strongly suggest that Vibrio P1 constitutes a homogeneous group on the basis of its antigenic characteristics. Although this microorganism shares common epitopes with several Vibrio species, antigenic heterogeneity with regard to both LPS-structure and OMP-pattern is presented.