Pseudorabies virus (PRV) strain with defects in gE, gC, and TK genes protects piglets against an emerging PRV variant

The prevalence of an emerging variant of the pseudorabies virus (PRV) has been causing serious losses to farmers in China. Moreover, the commercially available PRV vaccine often fails to provide thorough protection. Therefore, in this study, we generated a PRV-∆gC\gE∆TK strain with defects in gC, gE, and TK of PRV. Compared to the parental PRV strain and the single gene deletion strains (PRV-∆gC, PRV-∆gE, and PRV-∆TK), PRV-∆gC\gE∆TK grew slowly, and exhibited fewer and smaller plaques on swine testis (ST) cells. Furthermore, animal experiment results showed that mice that were immunized intramuscularly with PRV-∆gC\gE∆TK, survived throughout the experiment with no observed clinical symptoms, and were completely protected against PRV challenge. Additionally, deletion of the gC, gE, and TK genes significantly alleviated viral damage in the brain. Furthermore, one-day-old weaned piglets immunized intramuscularly with PRV-∆gC\gE∆TK elicited higher levels of gB antibodies against both the emerging PRV variant and the parental PRV, exhibited full protection against challenge with both variants, and showed neutralization capacity against PRV. These data suggest that PRV-∆gC\gE∆TK is a promising vaccine candidate for the control of pseudorabies.