MONOCLONAL-ANTIBODIES AGAINST VIBRIO-ANGUILLARUM-O2 AND VIBRIO-ORDALII IDENTIFY ANTIGENIC DIFFERENCES IN LIPOPOLYSACCHARIDE O-ANTIGENS

Monoclonal antibodies (mAbs) that recognize distinct species-specific antigenic epitopes in O-antigens from Vibrio anguillarum O2, O2a and c ertain O2b strains (mAb 7B4) and from Vibrio ordalii strains (mAbs A16 and 7D11) were generated. Western immunoblot analysis using these mAb s revealed that vibrio strains grown in the presence of fresh rainbow trout blood expressed lipopolysaccharide (LPS) with longer (high molec ular mass) O-antigens and extracellular capsular layers when compared to strains grown without rainbow trout blood. We also generated mAbs t hat react with O-antigens from V. anguillarum serotype O1 (mAbs 7Bs, 7 B5 and 1C3) and serotype O3 (mAbs 13A1 and 14C5) strains. These mAbs p rovide rapid and accurate diagnostic reagents for serological differen tiation of V. ordalii from serotype O2 strains of V. anguillarum, and for serotyping of these pathogenic vibrios.