title: Amino acid substitutions in the structural or nonstructural proteins of a vaccine strain of equine arteritis virus are associated with its attenuation.
abstract: Comparative sequence analysis of a series of strains of equine arteritis virus (EAV) of defined virulence for horses, ranging from the horse-adapted virulent Bucyrus (VB) strain to a fully attenuated vaccine strain derived from it, identified 13 amino acid substitutions associated with attenuation. These include 4 substitutions in the replicase proteins and 9 in the structural proteins. Using reverse genetic techniques, these amino acid substitutions were introduced into a virulent infectious cDNA clone pEAVrVBS derived from the VB strain of EAV. Inoculation of horses with the recombinant viruses clearly demonstrated that changes in either the replicase (nsp1, nsp2 and nsp7) or structural proteins (GP2, GP4, GP5 and M) resulted in attenuation of the virulent VB strain. The recombinant virus with substitutions in the structural proteins was more attenuated than the recombinant virus with substitutions only in the replicase proteins.
authors.affiliation: Department of Veterinary Science, Maxwell H. Gluck Equine Research Center, University of Kentucky, Lexington, KY 40546, USA.
authors.forename: Jianqiang
authors.initials: J
authors.lastname: Zhang
authors.forename: Yun Young
authors.initials: YY
authors.lastname: Go
authors.forename: N James
authors.initials: NJ
authors.lastname: MacLachlan
authors.forename: Barry J
authors.initials: BJ
authors.lastname: Meade
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Timoney
authors.forename: Udeni B R
authors.initials: UB
authors.lastname: Balasuriya
mesh_terms: D019943:Amino Acid Substitution / Q000235:genetics*; D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D018174:Arterivirus Infections / Q000662:veterinary*; D001831:Body Temperature; D007240:Equartevirus / Q000235:genetics* / Q000472:pathogenicity*; D006734:Horse Diseases / Q000821:virology*; D006736:Horses; D007962:Leukocytes / Q000821:virology; D018655:Lymphocyte Count; D008969:Molecular Sequence Data; D009296:Nasal Cavity / Q000821:virology; D009500:Neutralization Tests; D012367:RNA, Viral / Q000235:genetics; D011995:Recombination, Genetic; D017422:Sequence Analysis, DNA; D014613:Vaccines, Attenuated / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000235:genetics*; D010948:Viral Plaque Assay; D015678:Viral Structural Proteins / Q000235:genetics*; D014765:Viral Vaccines / Q000235:genetics
chemical_list: D000914:Antibodies, Viral; D012367:RNA, Viral; D014613:Vaccines, Attenuated; D017361:Viral Nonstructural Proteins; D015678:Viral Structural Proteins; D014765:Viral Vaccines