Adenovirus-based oral vaccine for rabbit hemorrhagic disease

Vaccine antigens for rabbit hemorrhagic disease virus (RHDV) are currently derived from inactivated RHDV obtained from the livers of experimentally infected rabbits or from several recombinant immunogens. However, the application of these vaccine antigens has been restricted because of biosecurity and immunity characteristics. In the current study, a recombinant adenovirus expressing the RHDV capsid protein (VP60) was constructed and the expression of the recombinant protein was identified through western blot analysis using RHDV-positive rabbit sera. Eighteen rabbits were immunized by injection, direct oral instillation, or using bait. They were challenged with RHDV isolate three weeks after boost immunization. In all cases, the rabbits immunized with the recombinant adenovirus developed RHDV-specific antibodies and cell immune response. The rabbits injected with the recombinant adenovirus were completely protected against RHDV challenge. The adenovirus expression system may provide a strategy for the immunization of rabbits, particularly for the control of RHDV in wild rabbits.