title: Development of a vaccine vector based on a subgenomic replicon of porcine reproductive and respiratory syndrome virus.
abstract: In this study, a DNA-launched subgenomic replicon of porcine reproductive and respiratory syndrome virus (PRRSV) was developed for use as a vaccine vector. This replicon plasmid contained a PRRSV subgenome without structural genes ORF2-ORF6, and was under the transcriptional control of the immediate-early promoter of cytomegalovirus (CMV). Using enhanced green fluorescent protein (EGFP) as a reporter gene, the DNA-launched subgenomic replicon of PRRSV, named pOK-Clone20-rep, could express heterologous genes in vitro. After direct inoculation of pOK-Clone20-rep, mice developed antibody responses that were specific for both the EGFP and the N gene in a dose-dependent manner. Furthermore, mice immunized with pOK-Clone20-rep at a dose of 100microg showed significantly enhanced levels of IFN-gamma compared with those inoculated with 100microg of pcD-EGFP, a conventional DNA vaccine that encodes EGFP. In summary, the results show that the DNA-launched subgenomic replicon of PRRSV could not only mediate foreign gene expression in vitro but also induced an immune response in vivo. Similarly, expression and immunogenicity of the N gene also strengthened the potential of the replicon to serve as a vaccine vector expressing multiple genes. It therefore provides a useful tool for vaccine development and the study of the transcription and replication of PRRSV.
authors.affiliation: Huazhong Agricultural University, Wuhan, Hubei, China.
authors.forename: Qinfeng
authors.initials: Q
authors.lastname: Huang
authors.forename: Qingxia
authors.initials: Q
authors.lastname: Yao
authors.forename: Huiying
authors.initials: H
authors.lastname: Fan
authors.forename: Shaobo
authors.initials: S
authors.lastname: Xiao
authors.forename: Youhui
authors.initials: Y
authors.lastname: Si
authors.forename: Huanchun
authors.initials: H
authors.lastname: Chen
mesh_terms: D000818:Animals; D003587:Cytomegalovirus / Q000235:genetics; D005260:Female; D017930:Genes, Reporter; D005822:Genetic Vectors; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000276:immunology; D007371:Interferon-gamma / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D010957:Plasmids; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics*; D012093:Replicon; D019444:Vaccines, DNA / Q000235:genetics / Q000276:immunology; D014764:Viral Proteins / Q000235:genetics / Q000276:immunology; D014765:Viral Vaccines / Q000235:genetics* / Q000276:immunology*
chemical_list: D019444:Vaccines, DNA; D014764:Viral Proteins; D014765:Viral Vaccines; D049452:Green Fluorescent Proteins; D007371:Interferon-gamma