Antigenic epitopes and MHC binders in OMP A of fish pathogen Edwardsiella tarda: A bioinformatic study

Edwardsiella tarda is a Gram-negative, facultative anaerobic, rod-shaped bacteria belonging to Enterobacteriaceae family that is recognized as the causative agent of the disease ‘edwardsiellosis’ in fresh water fish such as carp, tilapia and catfish, characterized by septicemia, extensive skin lesions and swelling. The virulence factors involved in the pathogenicity of this bacterium are largely unknown. In several Gram-negative bacteria, the surface associated outer membrane proteins (OMPs) are being increasingly recognized as potential targets for inducing protective immune response in fish and other vertebrates and are of interest in vaccine development. Although a few studies have recognised the importance of OMPs in virulence of E. tar da, and while some of these proteins have been characterized, to our knowledge there are no published reports on E. tarda OMP A and its potential as a vaccine candidate. In this study we analyzed OMP A of E. tarda using bioinformatics tools to determine the antigenic sites, B cell epitopes and MHC binding peptides. The exposed regions of the protein obtained from solvent accessibility analysis are the most probable antigenic sites. The transmembrane region of the protein and its secondary structure is also presented.