ABSTRACT
We have previously evaluated a Semliki Forest virus (SFV) replicon vectored DNA vaccine (pSFV1CS2-E2) and a recombinant adenovirus (rAdV-E2) expressing the E2 glycoprotein of classical swine fever virus (CSFV) in pigs. The results showed that the immunized pigs were protected from virulent challenge, but few pigs showed short-term fever and occasional pathological changes following virulent challenge. To enhance the immunogenecity of the vaccines, we tried a prime-boost vaccination strategy using a combination of prime with pSFV1CS2-E2 followed by boost with rAdV-E2. The results showed that all the immunized pigs developed high-level CSFV-specific antibodies following prime-boost immunization. When challenged with virulent CSFV, the immunized pigs (n = 5) from the heterologous boost group showed no clinical symptoms, and CSFV RNA was not detected following challenge, whereas one of five pigs from the homologous boost group developed short-term fever and CSFV RNA was detected. This demonstrates that the heterologous prime-boost vaccination regime has the potential to prevent against virulent challenge.
Subject(s)
Animals , Adenoviridae , Genetics , Metabolism , Adenovirus E2 Proteins , Genetics , Allergy and Immunology , Classical Swine Fever , Allergy and Immunology , Classical Swine Fever Virus , Genetics , Allergy and Immunology , Genetic Vectors , Immunization, Secondary , Replicon , Genetics , Semliki forest virus , Genetics , Metabolism , Swine , Vaccines, DNA , Allergy and Immunology , Viral Envelope Proteins , Genetics , Metabolism , Viral Vaccines , Allergy and ImmunologyABSTRACT
Classical swine fever (CSF), which is caused by classical swine fever virus (CSFV), causes significant losses in pig industry in many countries in Asia and Europe. The E2 glycoprotein of CSFV is the main target for neutralizing antibodies. In this study, a recombinant replication-defective human adenovirus expressing the CSFV E2 gene (rAdV-E2) was generated and evaluated for the immunogenicity in rabbits. The results showed that the rabbits immunized with rAdV-E2 developed high-level CSFV-specific antibodies. The rAdV-E2-immunized rabbits were all free of the regular fever and the viral replication in the spleen upon challenge with C-strain, which were seen in the rabbits immunized with the parent adenovirus of rAdV-E2. This indicates that the recombinant adenovirus can be an attractive candidate vaccine against CSF.
Subject(s)
Animals , Rabbits , Adenoviridae , Genetics , Allergy and Immunology , Metabolism , Antibodies, Viral , Blood , Genetic Vectors , Genetics , Immunization , Random Allocation , Recombinant Proteins , Genetics , Allergy and Immunology , Transfection , Viral Envelope Proteins , Genetics , Allergy and Immunology , Viral Vaccines , Allergy and ImmunologyABSTRACT
Baculovirus-mediated gene transfer into mammalian cells has been used to develop non-replicative vector vaccines against a number of diseases in several animal models.A baculovirus pseudotyped with the glycoprotein of vesicular stomatitis virus was used as vector to construct the recombinant baculovirus expressing classical swine fever virus(CSFV) E2 protein under the control of ie1 promoter from white spot syndrome virus.The E2 gene was shown to be efficiently expressed in both insect and mammalian cells.Intramuscular injection of mice with the recombinant baculovirus resulted in the production of high-level CSFV-specific antibodies.Specific lymphoproliferative responses to the CSFV stimulation were induced in the splenocytes of the immunized mice as demonstrated by CFSE staining assay and WST-8 assay.The results indicates that the pseudotyped baculovirus-delivered gene can be a potential non-replicative vaccine against CSFV infection.