Self-assembled nanoparticle vaccine based on the grass carp ferritin remarkably enhance the protective immune responses against GCRV type II infection

Globally, grass carp reovirus (GCRV) is one of the major etiological agents that cased serve harm to grass carp breeding industry. Vaccination is recognized as an economical and safety method to prevent GCRV infection. Previous researches have shown that ferritin-based nanoparticle vaccines have great potential in treating of viral diseases. In this study, the highly immunogenic fragment VP4-3 and VP56-2 from GCRV were chosen as antigens, grass carp ferritin was used as platform. Based on this, two nanoparticle vaccines VP4-3-Fn and VP56-2-Fn were subsequently constructed and used to immunized grass carp by bath treatment. The immune effect of VP4-3-Fn and VP56-2-Fn were evaluated by detecting serum specific antibody level, enzyme activities, and expression level of genes related to immune response. The results revealed that those index in grass carp vaccinated with VP4-3-Fn/VP56-2-Fn were increased significantly than those in grass carp vaccinated with VP4-3/VP56-2, respectively. In addition, the relative precent survival of VP4-3-Fn/VP56-2-Fn group were 53.85 % and 46.15 % respectively, compared with that of VP4-3 group (26.92 %) and VP56-2 group (23.08 %). Thus, our study demonstrates that grass carp ferritin can be used as a promising nanoparticle for rational design of aquatic vaccines.