Chimeric PRRSv confers cross-protection in pigs

Virology. 2015 Sep 2;485:402-413. doi: 10.1016/j.virol.2015.08.021. [Epub ahead of print]

Chimeric porcine reproductive and respiratory syndrome virus containing shuffled multiple envelope genes confers cross-protection in pigs.

Tian D¹, Ni YY¹, Zhou L¹, Opriessnig T², Cao D¹, Piñeyro P³, Yugo DM¹, Overend C¹, Cao Q¹, Lynn Heffron C¹, Halbur PG⁴, Pearce DS⁵, Calvert JG⁵, Meng XJ⁶.

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Abstract

The extensive genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV) strains is a major obstacle for vaccine development. We previously demonstrated that chimeric PRRSVs in which a single envelope gene (ORF3, ORF4, ORF5 or ORF6) was shuffled via DNA shuffling had an improved heterologous cross-neutralizing ability. In this study, we incorporate all of the individually-shuffled envelope genes together in different combinations into an infectious clone backbone of PRRSV MLV Fostera^® PRRS. Five viable progeny chimeric viruses were rescued, and their growth characteristics were characterized in vitro. In a pilot pig study, two chimeric viruses (FV-SPDS-VR2,FV-SPDS-VR5) were found to induce cross-neutralizing antibodies against heterologous strains. A subsequent vaccination/challenge study in 72 pigs revealed that chimeric virus FV-SPDS-VR2 and parental virus conferred partial cross-protection when challenged with heterologous strains NADC20 or MN184B. The results have important implications for future development of an effective PRRSV vaccine that confers heterologous protection.
Copyright © 2015 Elsevier Inc. All rights reserved.

KEYWORDS:

Cross-protection; DNA shuffling; Envelope genes; Heterologous strains; Porcine reproductive and respiratory syndrome virus (PRRSV); Vaccines

PMID: 26342466 [PubMed - as supplied by publisher]