title: A highly pathogenic porcine reproductive and respiratory syndrome virus generated from an infectious cDNA clone retains the in vivo virulence and transmissibility properties of the parental virus.
abstract: The nucleotide sequence of a highly pathogenic porcine reproductive and respiratory syndrome virus (PRRSV) was determined. Transfection of MARC-145 cells with capped in vitro transcripts derived from a full-length cDNA clone of the viral genome resulted in infectious PRRSV with growth characteristics similar to that of the parental virus. Primer extension analysis revealed that during replication, the viral polymerase corrected the two nonviral guanosine residues present at the 5' terminus of the transfected transcripts. Animal studies showed that the cloned virus induced hyperthermia, persistent viremia, and antibody response, similar to that observed with the parental virus. Contact transmission occurred rapidly within 3 days of introduction of naïve pigs into the group of clone virus-inoculated pigs. These results suggest that the cloned virus retains the in vivo virulence and contagion properties of the parental virus, thus, providing the background for reverse genetics manipulation in systematic examination of attenuation and virulence phenotypes.
authors.affiliation: Department of Veterinary and Biomedical Sciences and the Nebraska Center for Virology, University of Nebraska, Lincoln, NE 68588, USA.
authors.forename: Ha M
authors.initials: HM
authors.lastname: Truong
authors.forename: Z
authors.initials: Z
authors.lastname: Lu
authors.forename: Gerald F
authors.initials: GF
authors.lastname: Kutish
authors.forename: Judith
authors.initials: J
authors.lastname: Galeota
authors.forename: Fernando A
authors.initials: FA
authors.lastname: Osorio
authors.forename: Asit K
authors.initials: AK
authors.lastname: Pattnaik
mesh_terms: D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D004279:DNA, Viral / Q000235:genetics*; D016679:Genome, Viral; D019318:Porcine Reproductive and Respiratory Syndrome / Q000635:transmission / Q000821:virology; D019316:Porcine respiratory and reproductive syndrome virus / Q000235:genetics* / Q000472:pathogenicity* / Q000502:physiology; D034421:Sus scrofa; D014774:Virulence / Q000235:genetics; D014779:Virus Replication
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D004279:DNA, Viral