title: Rapid, specific detection of alphaviruses from tissue cultures using a replicon-defective reporter gene assay.
abstract: We established a rapid, specific technique for detecting alphaviruses using a replicon-defective reporter gene assay derived from the Sindbis virus XJ-160. The pVaXJ expression vector containing the XJ-160 genome was engineered to form the expression vectors pVaXJ-EGFP expressing enhanced green fluorescence protein (EGFP) or pVaXJ-GLuc expressing Gaussia luciferase (GLuc). The replicon-defective reporter plasmids pVaXJ-EGFPΔnsp4 and pVaXJ-GLucΔnsp4 were constructed by deleting 1139 bp in the non-structural protein 4 (nsP4) gene. The deletion in the nsP4 gene prevented the defective replicons from replicating and expressing reporter genes in transfected BHK-21 cells. However, when these transfected cells were infected with an alphavirus, the non-structural proteins expressed by the alphavirus could act on the defective replicons in trans and induce the expression of the reporter genes. The replicon-defective plasmids were used to visualize the presence of alphavirus qualitatively or detect it quantitatively. Specificity tests showed that this assay could detect a variety of alphaviruses from tissue cultures, while other RNA viruses, such as Japanese encephalitis virus and Tahyna virus, gave negative results with this system. Sensitivity tests showed that the limit of detection (LOD) of this replicon-defective assay is between 1 and 10 PFU for Sindbis viruses. These results indicate that, with the help of the replicon-defective alphavirus detection technique, we can specifically, sensitively, and rapidly detect alphaviruses in tissue cultures. The detection technique constructed here may be well suited for use in clinical examination and epidemiological surveillance, as well as for rapid screening of potential viral biological warfare agents.
authors.affiliation: Department of Viral Encephalitis, Institute for Viral Disease Control and Prevention, Chinese Center for Disease Control and Prevention, State Key Laboratory for Infectious Disease Prevention and Control, Beijing, China.
authors.forename: Jiangjiao
authors.initials: J
authors.lastname: Li
authors.forename: Wuyang
authors.initials: W
authors.lastname: Zhu
authors.forename: Huanqin
authors.initials: H
authors.lastname: Wang
authors.forename: Jiandong
authors.initials: J
authors.lastname: Li
authors.forename: Quanfu
authors.initials: Q
authors.lastname: Zhang
authors.forename: Ying
authors.initials: Y
authors.lastname: He
authors.forename: Jia
authors.initials: J
authors.lastname: Li
authors.forename: Juanjuan
authors.initials: J
authors.lastname: Fu
authors.forename: Dexin
authors.initials: D
authors.lastname: Li
authors.forename: Guodong
authors.initials: G
authors.lastname: Liang
mesh_terms: D000524:Alphavirus / Q000254:growth & development / Q000302:isolation & purification*; D018354:Alphavirus Infections / Q000175:diagnosis* / Q000235:genetics; D017930:Genes, Reporter / Q000235:genetics*; D005818:Genetic Engineering / Q000379:methods; D005822:Genetic Vectors / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D057230:Limit of Detection; D012680:Sensitivity and Specificity; D012845:Sindbis Virus / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000235:genetics; D010948:Viral Plaque Assay / Q000379:methods*
chemical_list: D017361:Viral Nonstructural Proteins; D049452:Green Fluorescent Proteins