The 135 Gene of Goatpox Virus Encodes an Inhibitor of NF-κB and Apoptosis and May Serve as an Improved Insertion Site To Generate Vectored Live Vaccine

Abstract

Goatpox virus (GTPV) is an important member of the genus of the Capripoxviruses have large and complex DNA genomes encoding many unknown proteins that may contribute to virulence. We identified that the open reading frame of GTPV is an early gene that encodes an ∼18-kDa protein that is nonessential for viral replication in cells. This protein functioned as an inhibitor of NF-κB activation and apoptosis and is similar to the N1L protein of vaccinia virus. In the natural host, sheep, deletion of the gene from the GTPV live vaccine strain AV41 resulted in less attenuation than that induced by deletion of the gene, a well-defined nonessential gene in the poxvirus genome. Using the gene as the insertion site, a recombinant AV41 strain expressing hemagglutinin of peste des petits ruminants virus (PPRV) was generated and elicited stronger neutralization antibody responses than those obtained using the traditional gene as the insertion site. These results suggest that the gene of GTPV encodes an immunomodulatory protein to suppress host innate immunity and may serve as an optimized insertion site to generate capripoxvirus-vectored live dual vaccines. Capripoxviruses are etiological agents of important diseases in sheep, goats, and cattle. There are rare reports about viral protein function related to capripoxviruses. In the present study, we found that the 135 protein of GTPV plays an important role in inhibition of innate immunity and apoptosis in host cells. Use of the gene as the insertion site to generate a vectored vaccine resulted in stronger adaptive immune responses than those obtained using the locus as the insertion site. As capripoxviruses are promising virus-vectored vaccines against many important diseases in small ruminants and cattle, the gene may serve as an improved insertion site togenerate recombinant capripoxvirus-vectored live dual vaccines.

Extended sequencing of vaccine and wild‐type capripoxvirus isolates provides insights into genes modulating virulence and host range

“…The use of a specifically modified capripoxvirus as a live‐attenuated vaccine has been proposed and demonstrated as feasible by inactivating the kelch‐like gene (SPPV_019) in SPPV‐SA (Balinsky et al, ). More recently, Zhang, Sun, Chen, and Bu () showed that deleting a putative NF‐kB inhibitor (GTPV_135) enhanced antibody responses to a GTPV‐encoded peste des petits ruminants hemagglutinin. A long‐term goal in such vaccine development programmes would be to gain a better understanding of factors affecting the host range of these viruses.…”

Adaptation and Comparative Growth Behaviour of Egyptian SPV isolates in Vero

“…This was the same observed by Zhuetal. (2013) and Zhang et al (2018). Finally, after adaptation of SPV isolates, and investigation of some characters including the growth curve and growth kinetics of these SPV isolate, further studies are recommended for SPV vaccine preparation, that not only used for giving protection to sheep, but also can be used to vaccinate cattle under stress factors against LSDV.…”

“…Multiplicity of infection (MOI) is a critical factor that must be carefully determined as it influences the virus growth dynamic and virus yield (Genzel et al, 2006;Trabelsi et al, 2012;Trabelsi et al, 2014) succeeded to adapt SPV (RM65 strain) firstly on lamb kidney cells, then on Vero cells after nine passages with MOI of 0.005, yielded a higher virus titer when compared to that achieved at a MOI of 0.001. For determination of virus particles inside the culture, Zhang et al (2018) applied indirect immunofluorescence assay when infected Lamb Testis (LT) cells with AV41(a strain of GPV) or its recombinants at an MOI of 0.05. In our study, we aim to use the lowest MOI which provides the highest titer with the optimum virus harvestation time.…”

Capripoxvirus Infections in Ruminants: A Review

“…The use of poxviruses as vaccine vectors in recombinant vaccines presents many advantages such as the large size of the viral genome (140–300 kbp) which can contain up to 25,000 bases of foreign DNA, their thermal stability, and their replication in the cytoplasm of infected cells without integration into the host genome. Several recombinant capripoxvirus-vectored vaccines have been generated using genes of Rift Valley fever [ 137 , 138 ], peste des petits ruminants [ 139 , 140 , 141 , 142 ], rinderpest [ 143 ], bluetongue [ 144 , 145 ]), foot-and-mouth disease virus Mp1-2A polyprotein [ 146 ], EG95 antigens from Echinococcus granulosus [ 147 ], and OMP25 outer membrane protein from Brucella [ 148 ]. Developed recombinant capripox vaccines have not yet been used at a large scale in the field despite having the ability to differentiate them between infected and vaccinated animals (DIVA).…”