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Open Access Research

Orf virus DNA vaccines expressing ORFV 011 and ORFV 059 chimeric protein enhances immunogenicity

Kui Zhao1, Wenqi He1, Wei Gao2, Huijun Lu3, Tiesuo Han1, Jing Li1, Ximu Zhang4, Bingbing Zhang1, Gaili Wang1, Gaoli Su1, Zhihui Zhao1, Deguang Song1* and Feng Gao13*

Author Affiliations

1 College of Animal Science and Veterinary Medicine, Jilin University, Changchun 130062, China

2 Laboratory Animal Center, Jilin University, Changchun 130062, China

3 Key Laboratory of Zoonosis, Ministry of Education, Institute of Zoonosis and Animal Research Center, Jilin University, Changchun 130062, China

4 Laboratory Animal Center, Peking University, Beijing 100871, China

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Virology Journal 2011, 8:562  doi:10.1186/1743-422X-8-562

Published: 29 December 2011

Abstract

Background

ORFV attenuated live vaccines have been the main prophylactic measure against contagious ecthyma in sheep and goats in the last decades, which play an important role in preventing the outbreak of the disease. However, the available vaccines do not induce lasting immunity in sheep and goats. On the other hand, variation in the terminal genome of Orf virus vaccine strains during cell culture adaptation may affect the efficacy of a vaccine. Currently, there are no more effective antiviral treatments available for contagious ecthyma.

Results

We constructed three eukaryotic expression vectors pcDNA3.1-ORFV011, pcDNA3.1-ORFV059 and pcDNA3.1-ORFV011/ORFV059 and tested their immunogenicity in mouse model. High level expression of the recombinant proteins ORFV011, ORFV059 and ORFV011/ORFV059 was confirmed by western blotting analysis and indirect fluorescence antibody (IFA) tests. The ORFV-specific antibody titers and serum IgG1/IgG2a titers, the proliferation of lymphocytes and ORFV-specific cytokines (IL-2, IL-4, IL-6, IFN-γ, and TNF-α) were examined to evaluate the immune responses of the vaccinated mice. We found that mice inoculated with pcDNA3.1-ORFV 011/ORFV059 had significantly stronger immunological responses than those inoculated with pcDNA3.1-ORFV011, pcDNA3.1-ORFV059, or pcDNA3.1-ORFV011 plus pcDNA3.1-ORFV059. Compared to other vaccine plasmids immunized groups, pcDNA3.1-ORFV011/ORFV059 immunized group enhances immunogenicity.

Conclusions

We concluded that DNA vaccine pcDNA3.1-ORFV011/ORFV059 expressing ORFV011 and ORFV059 chemeric-proteins can significantly improve the potency of DNA vaccination and could be served as more effective and safe approach for new vaccines against ORFV.