Protective antigenicity of 37 kDa outer membrane protein of Edwardsiella tarda against different serotype strains

Abstract

An outer membrane protein (OMP) of the fish pathogenic bacterium Edwardsielia tarda was investigated on its antigenic property. Bacterial agglutination reaction and SDS-PAGE /westem blotting analysis using selected rabbit antisera demonstrated that a 37 kDa OMP was a common antigen among 17 E. tarda strains. Immunoelectron microscopy demonstrated that the 37 kDa OMP located on/in the outer membrane of the bacterium. Immunization of Japanese eel with the 37 kDa OMP prepared from two different serotype strains showed protection against intraperitoneal injection with one strain. Immunization of Japanese flounder with the 37 kDa OMP prepared from one strain also showed protection against injection with two different serotype strains. The results indicate that the 37 kDa OMP is a cell surface protective antigen commonly effective against different serotypes of E. tarda.