Recombinant snakehead rhabdovirus-mediated expression of white spot syndrome virus (WSSV) VP28 confers protection against WSSV in Penaeus vannamei.

White spot syndrome virus (WSSV) is a major pathogen responsible for significant economic losses in global shrimp aquaculture. In this study, we developed a recombinant snakehead rhabdovirus (rSHRV) expressing the WSSV VP28 envelope protein (designated rSHRV-AVP28) and evaluated its potential as a vaccine candidate for Penaeus vannamei. The VP28 gene was successfully inserted between the N and P genes of the SHRV genome, and the rescued virus demonstrated plaque formation and intracellular VP28 expression, although the antigen was not incorporated into viral particles. Vaccination with rSHRV-AVP28 significantly reduced cumulative mortality to ∼30 % upon WSSV challenge, compared to 100 % mortality in both buffer- and vector-control groups. Quantitative PCR revealed a 10,000-fold reduction in WSSV viral load in the rSHRV-AVP28 group, with surviving shrimp exhibiting viral titers below 104 copies/mg of muscle tissue. These results demonstrate that rSHRV-AVP28 effectively induces protective immunity in shrimp, highlighting the potential of rhabdovirus-based vectors as novel delivery platforms for crustacean vaccines.