Vaccination is one of the most effective and economic way to prevent
infectious diseases in aquaculture. The development of effective
vaccines, however, is still limited, especially for
polyvalent vaccines, which are against multiple species. With this regard, identification of polyvalent protective immunogens, serving as
polyvalent vaccines, became a key step in
vaccine development. In the current study, 17 outer
membrane proteins from Vibrio parahaemolyticus were identified as immunogens. Further, four of the 17
proteins including VP2309, VP0887, VPA0548 and VP1019 were characterized as efficiently protective immunogens against V. parahaemolyticus'
infection through passive and active immunizations in zebrafish. Importantly, these four
proteins showed cross-protective capability against
infections by Aeromonas hydrophila or/and Pseudomonas fluorescens, which shared similar
epitopes with V. parahaemolyticus in homology of these
proteins. Further investigation showed that the expression level of the four protective immunogens elevated in response to fish plasma in a dose-dependent manner. These results indicate that the four protective immunogens are
polyvalent vaccine candidates in aquaculture.