Comparative Reverse Vaccinology of Piscirickettsia salmonis, Aeromonas salmonicida, Yersinia ruckeri, Vibrio anguillarum and Moritella viscosa, Frequent Pathogens of Atlantic Salmon and Lumpfish Aquaculture

Abstract

Marine finfish aquaculture is affected by diverse infectious diseases, and they commonly occur as co-infection. Some of the most frequent and prevalent Gram-negative bacterial pathogens of the finfish aquaculture include Piscirickettsia salmonis, Aeromonas salmonicida, Yersinia ruckeri, Vibrio anguillarum and Moritella viscosa. To prevent co-infections in aquaculture, polyvalent or universal vaccines would be ideal. Commercial polyvalent vaccines against some of these pathogens are based on whole inactivated microbes and their efficacy is controversial. Identification of common antigens can contribute to the development of effective universal or polyvalent vaccines. In this study, we identified common and unique antigens of P. salmonis, A. salmonicida, Y. ruckeri, V. anguillarum and M. viscosa based on a reverse vaccinology pipeline. We screened the proteome of several strains using complete available genomes and identified a total of 154 potential antigens, 74 of these identified antigens corresponded to secreted proteins, and 80 corresponded to exposed outer membrane proteins (OMPs). Further analysis revealed the outer membrane antigens TonB-dependent siderophore receptor, OMP assembly factor BamA, the LPS assembly protein LptD and secreted antigens flagellar hook assembly protein FlgD and flagellar basal body rod protein FlgG are present in all pathogens used in this study. Sequence and structural alignment of these antigens showed relatively low percentage sequence identity but good structural homology. Common domains harboring several B-cells and T-cell epitopes binding to major histocompatibility (MHC) class I and II were identified. Selected peptides were evaluated for docking with Atlantic salmon (Salmo salar) and Lumpfish MHC class II. Interaction of common peptide-MHC class II showed good in-silico binding affinities and dissociation constants between −10.3 to −6.5 kcal mol−1 and 5.10 × 10−9 to 9.4 × 10−6 M. This study provided the first list of antigens that can be used for the development of polyvalent or universal vaccines against these Gram-negative bacterial pathogens affecting finfish aquaculture.

Host–Pathogen Interactions of Marine Gram-Positive Bacteria

“…These available genomes open exciting opportunities in the search for universal vaccine candidates across the fish pathogens and shed light on using reverse vaccinology approaches. For example, a recent study used a reverse vaccinology pipeline to identify a set of antigens that could be used to develop a polyvalent vaccine against Gram-negative bacterial infections that impact Atlantic salmon and lumpfish aquaculture [ 234 ]. Vaccines against marine Gram-positive bacterial infections could be developed using similar techniques.…”

Strategies for Prevention and Control of Vibriosis in Asian Fish Culture

“…At the same time, another study has pointed out the limitation of recombinant OmpK in preparing diagnostic antibodies [ 44 ]. For this reason, using modern methods for understanding and developing new V. parahaemolyticus immunogenic proteins and antibodies are necessary [ 45 , 46 ].…”

“…To create the ideal novel vaccine, undoubtedly, the most significant part will be the identification of common antigens [ 45 ]. The use of modern reverse vaccinology could make it come true by predicting potential protective antigens and epitopes, which could aid in narrowing down peptide selection in designing suitable vaccines [ 80 ].…”

Isolation and Characterization of a Novel Virulent Phage ASG01 of Aeromonas salmonicida and Its Cell Wall Hydrolase Activity

“…The Gram-negative bacterium Aeromonas salmonicida , which is the only non-motile species in the genus Aeromonas [ 1 ], is responsible for typical furunculosis and bacterial septicemia and has been considered as one of the most important pathogens in a variety of fish species in aquaculture [ 2 , 3 , 4 , 5 ], causing significant economic losses in aquaculture [ 6 ]. Recently, A. salmonicida was isolated from the human blood in a case report [ 7 ].…”