Bacterial ghost as delivery vehicles loaded with DNA vaccine induce significant and specific immune responses in common carp against spring viremia of carp virus

摘要

Although vaccine is a prophylaxis measure for the contagious and fatal disease caused by spring viremia of carp virus (SVCV), until now, no commercial vaccine is available for worldwide use. To find more effective and safe means for the control of SVCV infection, here, an Escherichia coil DH5 alpha bacterial ghost (DH5 alpha-BG, non-living bacterial) based DNA vaccine delivery system (BG/pEG-G) was constructed. Carp were injected intramuscularly by different treatments (PBS, pEGFP, BG, pEG-G and BG/pEG-G), and the immunoprotective effect induced by these treatments were analyzed. We found a stronger and longer duration immune response (serum antibody production and immune-related genes expression) can be induced in fish vaccinated with BG/pEG-G in comparison with those vaccinated with pEG-G alone. Additionally, a good immune protective effect (relative percentage survival & 81.48%) was observed in fish vaccinated with BG/pEG-G vaccine at the dose of 0.2 mu g DNA/g of fish. Overall, this study for the first time demonstrates the ability of DH5 alpha-BG as DNA vaccine carrier against SVCV infection in carps, suggesting a practical multivalent strategy for the control of aquatic disease.