Application of reverse vaccinology for designing of an mRNA vaccine against re-emerging marine birnavirus affecting fish species

Marine birnavirus (MABV) has been the most pathogenic virus for marine and shellfish species across the world in terms of production and financial benefits. An outbreak of the disease may lead to entire mortality within a short period under standard culture conditions. The sequencing and characterization of several MABV strains have begun to reveal information regarding pathogen biology and pathogenicity. The major capsid protein VP2 and RNA-dependent RNA polymerase (RdRp), as well as polyprotein of Lates calcarifer birnavirus, was determined from several marine birnavirus (MABV) strains from different host or geographic origins. Despite the devastating complications, there is very limited prevention or control for the virus. In this regard, an immunoinformatics method was used to generate an epitope-based vaccine against this pathogen. The immunodominant T-cell epitopes were identified using the most antigenic and pathogenic proteins of MABV. The final constructed vaccine sequence was developed to be immunogenic, non-allergenic as well as to have better solubility. Molecular dynamics simulation revealed significant binding stability and structural compactness. Finally, using Escherichia coli K12 as a model, codon optimization yielded ideal GC content and a higher CAI value, which was then included in the cloning vector pET2+ (a). Overall, our findings suggest that the suggested peptide vaccine might be a viable approach for MABV prevention.