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TLR-5 agonist Salmonella abortus equi flagellin FliC enhances FliC-gD-based DNA vaccination against equine herpesvirus 1 infection

Zhao, Yanan, Chang, Jianxin, Zhang, Baojiang, Tong, Panpan, Wang, Caidie, Ran, Duoliang, Su, Yan
Archives of virology 2019 v.164 no.5 pp. 1371-1382
DNA, Equid alphaherpesvirus 1, Salmonella, Western blotting, agonists, antibodies, cell-mediated immunity, flagellin, fluorescent antibody technique, horses, immunogenicity, industry, interferon-gamma, mice, morbidity, neonatal mortality, recombinant vaccines, respiratory tract diseases, vaccination, viral load
Equine herpesvirus 1 (EHV-1) induces serious respiratory infections, viral abortion, neurological signs, and neonatal mortality in horses. Despite the use of vaccines, EHV-1 infection also causes a high annual economic burden to the equine industry. The poor immunogenicity of and protection conferred by EHV-1 vaccines are the major factors responsible for the spread of EHV-1 infection. The present study examined the immunogenicity of a novel DNA vaccine co-expressing FliC, a flagellin protein, in Salmonella abortus equi and the gD protein of EHV-1. Mice and horses were immunized intramuscularly with the vaccine, and mice were challenged with EHV-1. Immunofluorescence and western blotting revealed that FliC and gD can be efficiently expressed in cells. This novel vaccine significantly increased gD-specific antibody and interferon gamma (IFN-γ) levels in immunized mice and horses. Compared with controls, the viral load and morbidity were markedly reduced in FliC-gD-immunized mice after they were challenged with EHV-1. Furthermore, the immunogenicity of FliC-gD in a natural host was tested. Our results indicate that vaccinated mice and horses exhibit increased humoral and improved cellular immune responses.