Enhancement of neutralizing humoral response of DNA vaccine against duck hepatitis B virus envelope protein by co-delivery of cytokine genes

We explored in the duck hepatitis B virus (DHBV) model the impact of duck interferon gamma (Du-IFNγ) or interleukin 2 (Du-IL2) co-delivery on humoral neutralizing response induced by DNA-based vaccine encoding DHBV preS/S large envelope protein. Co-delivery of either Du-IL2 or Du-IFNγ encoding plasmids considerably increased the magnitude of anti-preS humoral response. Moreover, co-administration of cytokine genes led to a significant (p < 0.001) enhancement of neutralizing anti-DHBV antibody response, which was more pronounced for Du-IFNγ. Our data suggest that co-delivery of cytokine and envelope protein encoding plasmids will be a valuable approach for the development of a potent therapeutic DNA vaccine against chronic hepatitis B.