A live, attenuated pseudorabies virus strain JS-2012 deleted for gE/gI protects against both classical and emerging strains

Emerging pseudorabies virus (PRV) variant have led to pseudorabies outbreaks in Chinese pig farms. The commercially available PRV vaccine provides poor protection against the PRV variant. In this study, a gE/gI deleted PRV strain JS-2012-Delta gE/gI was generated from a PRV variant strain using homologous DNA recombination. Compared to the parental strain JS-2012, JS-2012-Delta gE/gI grew slowly and showed small plaque morphology on Vero cells. The safety and immunological efficacy of JS-2012-Delta gE/gI was evaluated as a vaccine candidate. JS-2012-Delta gE/gI was avirulent to suckling piglets, but was able to provide full protection for young piglets against challenge with both the classical virulent PRV and the emerging PRV variant. After sows were vaccinated with the gE/gI-deleted strain, their suckling offspring were resistant to an otherwise lethal challenge with the classical and the variant PRV5. Piglets inoculated with JS-2012-Delta gE/gI did not develop PRV-specific gE-ELISA antibodies. Thus, JS-2012-Delta gE/gI appears to be a promising marker vaccine candidate to control PRV variant circulating in pig farms in China. (C) 2016 Elsevier B.V. All rights reserved.