Title: MUTATIONS IN THE GENOME OF PORCINE REPRODUCTIVE AND RESPIRATORY SYNDROME VIRUS RESPONSIBLE FOR THE ATTENUATION PHENOTYPE
Allende, R - UNIVERSITY OF NEBRASKA
Lu, Z - USDA, ARS, PIADC
Lewis, T - USDA, ARS, PIADC
Friesen, J - UNIVERSITY OF NEBRASKA
Galeota, J - UNIVERSITY OF NEBRASKA
Doster, Alan - UNIVERSITY OF NEBRASKA
Osorio, Fernando - UNIVERSITY OF NEBRASKA
Submitted to: Archives of Virology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 16, 1999
Publication Date: N/A
Interpretive Summary: We determined the complete genomic sequence of a non-virulent isolate of the porcine reproductive and respiratory syndrome virus (PRRSV). By comparison to the virulent virus from which it was derived, we identified 212 genomic sequence differences which resulted in 9 changes in 7 viral proteins. These changes may account for the dfferences in the ability of these two viruses to cause disease in swine.
Although live-attenuated vaccines have been used for some time to control clinical symptoms of the porcine reproductive and respiratory syndrome (PRRS), the molecular bases for the attenuated phenotype remain unclear. We had previously determined the genomic sequence of the pathogenic PRRSV 16244B. Limited comparisons of the structural protein coding sequence of an attenuated vaccine strain have shown 98% homology to the pathogenic 16244B. Here we have confirmed the attenuated phenotype and determined the genomic sequence of that attenuated PRRSV vaccine and compared it to its parental VR-2332 and the 16244B strains. The attenuated vaccine sequence was colinear with that of the strain 16244B sequence containing no gaps and 212 substitutions over 15,374 determined nucleotide sequence. We identified nine amino acid changes distributed in Nsp1beta, Nsp2, Nsp10, ORF2, ORF3, ORF5 and ORF6. These changes may provide the molecular bases for the observed attenuated phenotype.