Immunoinformatics-based design and evaluation of a multi-epitope vaccine against Vibrio fluvialis

Vibrio fluvialis is an emerging foodborne pathogen causing gastroenteritis and extraintestinal infections, representing a significant public health concern due to rising antimicrobial resistance and the absence of an approved vaccine. This study aimed to design a multi-epitope subunit vaccine against V. fluvialis using immunoinformatics and a standard multi-epitope vaccine design pipeline. Two surface-exposed immunogenic membrane proteins, ATP-dependent zinc metalloprotease FtsH and lytic murein transglycosylase F, were selected as antigenic targets. Ten epitopes, including four MHC class I, four MHC class II, and two B-cell epitopes, were predicted and assembled into a 246 amino acid vaccine construct. The construct showed an antigenicity score of 0.8610. Population coverage analysis indicated that these epitopes could potentially cover 99.97% of the global population. The vaccine exhibited favorable physicochemical properties, with an instability index of 33.18 and a GRAVY score of - 0.282, suggesting stability and hydrophilicity. The tertiary structure was modeled using AlphaFold3 and docked with Toll-like receptor 2, yielding a docking score of - 270.01. Molecular dynamics simulations for 100 ns suggested stability of the vaccine-TLR2 complex. Codon optimization indicated high expression potential in Escherichia coli, with a CAI value of 0.95. Overall, the vaccine showed strong in silico immunogenic potential and requires further experimental validation through in vitro and in vivo studies.