Construction of a quadruple gene-deleted vaccine confers complete protective immunity against emerging PRV variant challenge in piglets

Leqiang Sun; Yajie Tang; Keji Yan; Huawei Zhang

doi:10.1186/s12985-022-01748-8

Construction of a quadruple gene-deleted vaccine confers complete protective immunity against emerging PRV variant challenge in piglets

Virol J. 2022 Jan 25;19(1):19. doi: 10.1186/s12985-022-01748-8.

Authors

Leqiang Sun¹, Yajie Tang², Keji Yan¹, Huawei Zhang³

Affiliations

¹ State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
² Henan Joint International Research Laboratory of Veterinary Biologics Research and Application, Anyang Institute of Technology, Anyang, Henan, China.
³ State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, 430070, Hubei, China. ZHW@mail.hzau.edu.cn.

Abstract

Background: Pseudorabies virus (PRV) causes Aujeszky's disease or pseudorabies (PR) in pigs worldwide, which leads to heavy economic losses to the swine industry. Pigs are the natural host, meanwhile, animals such as dogs, cats, foxes, rabbits, cattle and sheep are susceptible to infection. In 2011, the emerging PRV variant led to the outbreak of PR in Bartha-K61 vaccinated pigs. The PR outbreaks demonstrated that the Bartha-K61 vaccine did not provide full protection against the emerging PRV variant. It is widely believed that PRV live attenuated vaccine could control PRV infection.

Methods: In this study, we developed a novel PRV live attenuated vaccine by deleting its gI, gE, US9, and US2 genes through CRISPR/Cas9, which was named PRV GDFS-delgI/gE/US9/US2.

Results: Safety experiments confirmed that PRV GDFS-delgI/gE/US9/US2 was safe for 5- to 7-day-old suckling piglets. Piglets immunized with the PRV GDFS-delgI/gE/US9/US2 vaccine did not produce PRV gE-specific antibodies but could generate PRV gB-specific antibodies and high neutralizing titers against the PRV GDFS strain (variant PRV strain) or PRV Ea strain (older PRV strain). After challenge with the emerging PRV GDFS variant, none of the piglets immunized with the PRV GDFS-delgI/gE/US9/US2 vaccine showed any clinical signs, and their rectal temperatures were normal. Moreover, the autopsy and histopathological analyses revealed that the piglets in the PRV GDFS-delgI/gE/US9/US2 vaccine group did not show apparent gross or pathological lesions. Furthermore, the piglets in the PRV GDFS-delgI/gE/US9/US2 vaccine groups did not present weight loss. According to the criteria of the OIE terrestrial manual, the results of the experiment confirmed that the PRV GDFS-delgI/gE/US9/US2 vaccine could provide full protection against the emerging PRV variant strain in piglets.

Conclusions: The PRV GDFS-delgI/gE/US9/US2 strain is a potential new live attenuated vaccine against emerging PRV variant strain infections in China.

Keywords: CRISPR/Cas9 technology; Pseudorabies virus; Safety and efficacy; gI/gE/US9/US2.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Gene Deletion
Herpesvirus 1, Suid* / genetics
Pseudorabies* / prevention & control
Swine
Swine Diseases*
Viral Envelope Proteins / genetics

Substances

Viral Envelope Proteins