A live attenuated Vibrio anguillarum vaccine induces efficient immunoprotection in Tiger puffer (Takifugu rubripes)

Tiger puffer (Takifugu rubripes) is becoming an economic promising aquaculture species in China. However, the development of Tiger puffer breeding industry is restricted by some serious aquatic disease such as vibriosis. An effective live attenuated vaccine MVAV6203 was developed in our previous studies by curing the virulence plasmid pEIB1 and unmarked inframe-deletion of the aroC gene from the virulent V. anguillarum. Here, we evaluated whether this live vaccine was suitable for Tiger puffer against disease caused by Vibrio genus. The live vaccine show virulence attenuation in both juvenile and adult fish vaccinated with either a single or high dose (50-fold single dose). In addition, administration of the live vaccine shew limited growth in fish and did not affect fish body weight significantly, with no adverse impact on growth between vaccinated and saline control fish. Furthermore, increased expression of cytokines involved in pro-inflammatory (IL-1β, TNFα and IL-6), cell-mediated immunity inducing (IL-12p35, IL-12p40 and IL-18), antiviral/intracellular pathogen killing (I-IFN-1, IFN-γ and Mx), peripheral T cell expansion and survival controlling (IL-2, IL-7 and IL-15) and antigen processing maker and anti-inflammatory (MHC I and IL-10) were elicited significantly after the vaccination. These cellular responses correlate with protection against virulent strain challenge and high RPS of 90.67% and 80.31% in juvenile and adult fish were obtained, respectively. These data indicated for the first time that the live attenuated V. anguillarum vaccine is suitably applied for the development of an effective and safe vaccine for prevention of vibriosis in Tiger puffer aquaculture industry.