Construction and Immunogenicity of a Recombinant Pseudorabies Virus Variant With TK/gI/gE/11k/28k Deletion

In China, the re-emerging pseudorabies virus (PRV) variant has caused large-scale outbreaks of pseudorabies in swine herds with classical PRV vaccine immunization since late 2011. Here, a recombinant PRV with TK/gI/gE/11k/28k deletion was constructed based on variant HN1201 strain isolated in 2012, by the bacterial artificial chromosome infectious clones. Compared with the parental virus, the recombinant PRV rHN1201(TK-/gE-/gI-/11k-/28k-) showed a similar virus grown curve and exhibited smaller plaques. The vaccination of rHN1201(TK-/gE-/gI-/11k-/28k-) could elicit an earlier and higher level of gB antibody, and the neutralizing antibodies elicited by rHN1201(TK-/gE-/gI-/11k-/28k-) were effective against both PRV classical and variant strains. Clinically, the body temperature of the pigs immunized with rHN1201(TK-/gE-/gI-/11k-/28k-) was significantly lower than that of the classical PRV vaccine immunized pigs, and the recombinant PRV could provide effective protection against the challenge with the PRV variant. These results imply that the rHN1201(TK-/gE-/gI-/11k-/28k-) could be a promising vaccine candidate for the prevention of the current epidemic of pseudorabies in China.

Automated summary

In China, a variant strain of pseudorabies virus (PRV) has caused large-scale outbreaks in swine herds vaccinated with classical PRV vaccines since 2011. Researchers have constructed a recombinant PRV based on the variant HN1201 strain, which showed similar growth characteristics and smaller plaques compared to the parental virus. Vaccination with this recombinant PRV elicited earlier and higher levels of antibodies, providing protective immunity against both classical and variant strains of PRV. Clinically, pigs immunized with the recombinant PRV showed lower body temperature and were protected against infection with the variant PRV strain. These results suggest that this recombinant PRV could be a promising vaccine candidate for preventing the current pseudorabies epidemic in China.