A Novel Multi-epitope Vaccine Based on Virulence Stimulating Two-component Protein EsrA Against Fish Pathogenic Edwardsiella tarda – An Immunoinformatic Approach

Abstract

Edwardsiellosis, caused by the gram-negative pathogen Edwardsiella tarda, is a major global aquaculture threat. Despite vaccination being a potential strategy, development of effective vaccines remains a challenge. The study aimed to develop a multi-epitope vaccine (EsrAmev) against virulent EsrA antigen in fish pathogenic E. tarda using an immunoinformatic approach. The study identified antigenic, non-allergenic, and nontoxic epitopes for cytotoxic T lymphocytes, helper T-lymphocytes, and linear Blymphocytes. They were combined to create the EsrAmev construct, with TLR4 agonist added for the immunogenicity. The physiochemical analysis of EsrAmev by ProtParam server showed a molecular weight of 29 kDa, an antigenicity score of 0.5966, and a solubility of 0.823563 with immunogenic, non-allergenic and non-toxic properties. Robetta, Mod, and Galaxy refiner servers refined the EsrAmev 3D structure, achieving 97.4% RAMA-favoured region, stable interactions, binding stability, and structural stiffness with TLR4 receptor. The EsrAmev construct, optimized for high immune responses in Escherichia coli K12 model, was successfully cloned into the pET28a (+) vector in silico for future wet lab applications. These findings suggests that the EsrAmev multi-epitope vaccine might have potential for the prophylaxis of E.tardacausing Fish Edwardsiellosis.