Expression of HA of HPAI H5N1 Virus at US2 Gene Insertion Site of Turkey Herpesvirus Induced Better Protection than That at US10 Gene Insertion SiteReport as inadecuate




Expression of HA of HPAI H5N1 Virus at US2 Gene Insertion Site of Turkey Herpesvirus Induced Better Protection than That at US10 Gene Insertion Site - Download this document for free, or read online. Document in PDF available to download.

Herpesvirus of turkey HVT is being widely used as a vector for development of recombinant vaccines and US2 and US10 genes are often chosen as insertion sites for targeted gene expression. However, the different effects of the two genes for generation of recombinant HVT vaccines were unknown. In order to compare the effects of inserted genes in the two sites on the efficacy of the recombinant vaccines, host-protective haemagglutinin HA gene of the highly pathogenic avian influenza virus HPAIV H5N1 was inserted into either US2 or US10 gene locus of the HVT. The resulting US2 rHVT-US2-HA or US10 rHVT-US10-HA recombinant HVT viruses were used to infect chicken embryo fibroblasts. Plaques and the growth kinetics of rHVT-US2-HA-infected chicken embryo fibroblasts were similar to those of parental HVT whereas rHVT-US10-HA infected chicken embryo fibroblasts had different growth kinetics and plaque formation. The viremia levels in rHVT-US10-HA virus-infected chickens were significantly lower than those of rHVT-US2-HA group on 28 days post infection. The vaccine efficacy of the two recombinant viruses against H5N1 HPAIV and virulent Marek-s disease virus was also evaluated in 1-day-old vaccinated chickens. rHVT-US2-HA-vaccinated chickens were better protected with reduced mortality than rHVT-US10-HA-vaccinated animals following HPAIV challenge. Furthermore, the overall hemaglutination inhibition antibody titers of rHVT-US2-HA-vaccinated chickens were higher than those of rHVT-US10-HA-vaccinated chickens. Protection levels against Marek-s disease virus challenge following vaccination with either rHVT-US2-HA or rHVT-US10-HA, however, were similar to those of the parental HVT virus. These results, for the first time, indicate that US2 gene provides a favorable foreign gene insertion site for generation of recombinant HVT vaccines.



Author: Hongbo Gao , Hongyu Cui , Xianlan Cui, Xingming Shi, Yan Zhao, Xiaoyan Zhao, Yanming Quan, Shuai Yan, Weiwei Zeng, Yunfeng Wang

Source: http://plos.srce.hr/



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