Outer membrane protein K as a subunit vaccine against V. anguillarum

Vibrio anguillarum has been described as a leading cause of disease in various species of aquatic animals from many parts of the world. Fish vaccination is a useful strategy for several disease problems in aquaculture. Outer membrane proteins of bacteria are considered ideal candidates for vaccine development. In the present study, OmpK gene of V. anguillarum was cloned and sequenced. The recombinant OmpK was overexpressed and purified by affinity chromatography on Ni-NTA Superflow resin. Immunoreactivity of the pure OmpK was studied by western blotting. The fresh water Indian major carp Labeo rohita (Hamilton, 1822) was well protected when challenged with V. anguillarum after vaccination with OmpK compared to non vaccinated fish. Specific antibody against OmpK and bacterial inhibition was detected in the vaccinated fish. Our results suggest OmpK as a candidate vaccine molecule against V. anguillarum.

► The OmpK gene was cloned, overexpressed and the recombinant protein purified.
► Increased serum inhibitory effect was observed in fish vaccinated with OmpK.
► Specificity by western blot and high titer of antibody in rabbit and fish was observed.
► The relative percent survival of OmpK vaccinated fish was significant.
► OmpK offers protection against V. anguillarum infection in fish