High reversion potential of a cell-adapted vaccine candidate against highly pathogenic porcine reproductive and respiratory syndrome.

摘要: Abstract Modified live vaccine (MLV) based on highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) is prone to quick reversion of virulence upon circulating in host animals. The objective this study was evaluate the potential HP-PRRSV MLV identify elements within genome contributing phenomenon. A blind passage, cell-adaptation strategy attempted attenuate a strain JX143, which isolated during atypical PRRS outbreak 2006. Two attenuated candidates passage 87 (JXM87) 105 (JXM105) used as MLVs showed best balance safety efficacy 4 week-old piglets (unpublished data). studies were performed assessed for through five back passages susceptible (21 ± 3 days age). Both results increase clinical signs, pyrexia lung lesions well decreased average daily weight gain 3 pigs clearly, it indicated that both regained virulence, irrespective level. Increase respective parameters accompanied by viremia piglets: JXM87 titer increased from Passage 1 (P1) 4.40 Lg TCID50/mL P4 5.75 TCID50/mL, JXM105 P1 3.78 6.42 TCID50/mL. Next generation sequencing (NGS) samples (serum, tissue) Sequence analysis comparing materials with their parental strains revealed 10 amino acid mutations proteins 14 9 JXM105, respectively. Interestingly, identical two candidates, located nsp1β, GP5a nsp10 coding regions, suggesting could contribute HP-PRRSV.