Protective effects of recombinant glycoprotein D based prime boost approach against duck enteritis virus in mice model.

Duck virus enteritis, also known as duck plague, is an acute herpes viral infection of ducks caused by duck enteritis virus (DEV). The method of repeated immunization with a live attenuated vaccine has been used for the prevention and control of duck enteritis virus (DEV). However, the incidence of the disease in vaccinated flocks and latency reactivation are the major constraints in the present vaccination programme. The immunogenicity and protective efficacy afforded by intramuscular inoculation of plasmid DNA encoding DEV glycoprotein D (pCDNA-gD) followed by DEV gD expressed in Saccharomyces cerevisia (rgD) was assessed in a murine model. Compared with mice inoculated with DNA (pCDNA-gD) or protein (rgD) only, mice inoculated with the combination of gD DNA and protein had enhanced ELISA antibody titers to DEV and had accelerated clearance of virus following challenge infection. Furthermore, the highest levels of lymphocyte proliferation response, IL-4, IL-12 and IFN-γ production were induced following priming with the DNA vaccine and boosting with the rgD protein. For instance, the specially designed recombinant DEV vector vaccine would be the best choice to use in ducks. It offers an excellent solution to the low vaccination coverage rate in ducks. We expect that the application of this novel vaccine in the near future will greatly decrease the virus load in the environment and reduce outbreaks of DEV in ducks.