%0 Journal Article
%T Immunogenicity study of OmpU subunit vaccine against Vibrio mimicus in yellow catfish, Pelteobagrus fulvidraco.
%A Fu Y
%A Zhang YA
%A Shen J
%A Tu J
%J Fish Shellfish Immunol
%V 108
%N 0
%D Jan 2021
%M 33285164
%F 4.622
%R 10.1016/j.fsi.2020.11.030
%X The outer membrane protein U (OmpU) is a conserved outer membrane protein in a variety of pathogenic Vibrio species and has been considered as a vital protective antigen for vaccine development. Vibrio mimicus (V. mimicus) is the pathogen causing ascites disease in aquatic animals. In this study, the prokaryotically expressed and purified His-tagged OmpU of V. mimicus (His-OmpU) was used as a subunit vaccine. The formalin inactivated V. mimicus, purified His tag (His-tag), and PBS were used as controls. The vaccinated yellow catfish were challenged with V. mimicus at 28 days post-vaccination, and the results showed that the His-OmpU and inactivated V. mimicus groups exhibited much higher survival rates than the His-tag and PBS groups. To fully understand the underlying mechanism, we detected the expression levels of several immune-related genes in the spleen of fish at 28 days post-vaccination and 24 h post-challenge. The results showed that most of the detected immune-related genes were significantly upregulated in His-OmpU and inactivated V. mimicus groups. In addition, we performed the serum bactericidal activity assay, and the results showed that the serum from His-OmpU and inactivated V. mimicus groups exhibited much stronger bactericidal activity against V. mimicus than those of His-tag and PBS groups. Finally, the serum agglutination antibody was detected, and the antibody could be detected in His-OmpU and inactivated V. mimicus groups with the antibody titers increasing along with the time post-vaccination, but not in His-tag or PBS group. Our data reveal that the recombinant OmpU elicits potent protective immune response and is an effective vaccine candidate against V. mimicus in yellow catfish.