Reverse vaccinology is a widely used approach that has facilitated the rapid identification of vaccine candidates suitable in vaccine development for pathogens. Vibrio anguillarum is a major pathogen responsible for vibriosis in fish and shellfish leading to huge economic losses to the aquaculture industry. Although commercial vaccines are available for fish against this bacterium they have their own limitations. In this study, we used the reverse vaccinology strategy to screen and identify V. anguillarum outer membrane proteins (OMPs) that could serve as vaccine candidates. Our analysis identified 23 antigenic outer membrane proteins which were highly conserved (>98% identity) across serovars of this bacterium. Of the 23, two were identified as outer membrane lipoproteins. Among the OMPs identified 18 were novel to this study and conserved across several Vibrio spp. with an identity of 21-93%. While the least (>48%) identity was observed for V. anguillarum ferrichrome-iron transporter protein, the highest identity (>80%) was seen for outer membrane proteins OmpK, BamA, OmpU, Fatty acid transporter, and two hypothetical proteins. These potential vaccine targets identified could contribute to the development of effective vaccine not only against V. anguillarum but also across other Vibrio spp. In addition, several B-cell and T-cell epitopes were predicted for the novel OMPs in this study which could aid in narrowing down peptide selection in designing a suitable epitope-based vaccine.
Keywords: Epitopes; MHC class proteins; Outer membrane proteins; Reverse vaccinology; Vaccine candidates; Vibrio anguillarum.