The Construction and Immunogenicity Analyses of Recombinant Pseudorabies Virus With NADC30-Like Porcine Reproductive and Respiratory Syndrome Virus-Like Particles Co-expression.

Jun Zhao,Yao Huang,Lei Xu,Yuancheng Zhou,Sirui Gu,Fengqing Li,Ling Zhu,Zhiwen Xu,Huidan Deng,Xianggang Sun

doi:10.3389/fmicb.2022.846079

Abstract

Porcine reproductive and respiratory syndrome (PRRS) and pseudorabies (PR) are highly infectious swine diseases and cause significant financial loss in China. The respiratory system and reproductive system are the main target systems. Previous studies showed that the existing PR virus (PRV) and PRRS virus (PRRSV) commercial vaccines could not provide complete protection against PRV variant strains and NADC30-like PRRSV strains in China. In this study, the PRV variant strain XJ and NADC30-like PRRSV strain CHSCDJY-2019 are used as the parent for constructing a recombinant pseudorabies virus (rPRV)-NC56 with gE/gI/TK gene deletion and co-expressing NADC30-like PRRSV GP5 and M protein. The rPRV-NC56 proliferated stably in BHK-21 cells, and it could stably express GP5 and M protein. Due to the introduction of the self-cleaving 2A peptide, GP5 and M protein were able to express independently and form virus-like particles (VLPs) of PRRSV in rPRV-NC56-infected BHK-21 cells. The rPRV-NC56 is safe for use in mice; it can colonize and express the target protein in mouse lungs for a long time. Vaccination with rPRV-NC56 induces PRV and NADC30-like PRRSV specific humoral and cellular immune responses in mice, and protects 100% of mice from virulent PRV XJ strain. Furthermore, the virus-neutralizing antibody (VNA) elicited by rPRV-NC56 showed significantly lower titer against SCNJ-2016 (HP-PRRSV) than that against CHSCDJY-2019 (NADC30-like PRRSV). Thus, rPRV-NC56 appears to be a promising candidate vaccine against NADC30-like PRRSV and PRV for the control and eradication of the variant PRV and NADC30-like PRRSV.

Highlights

Porcine reproductive and respiratory syndrome (PRRS) appeared in Europe and the United States in the 1990s and became a problem that plagued the global pig industry ever since
The TK gene of recombinant pseudorabies virus (rPRV)- gE/gI-NC-ORF5-6 was deleted by CRISPR/Cas9, and the recombinant virus rPRV- gE/gI/TK-NC-ORF5-6 was obtained (Figure 1B)
Ingelvac PRRS MLV (United States) and modified live virus (MLV) vaccine derived from classical PRRS virus (PRRSV) (VR2332) or HP-PRRSV (TJ and JXA1) have been reported to provide optimistic cross protection for some NADC30-like PRRSV strains isolated in China (Zhang et al, 2018; Wei et al, 2019; Chai et al, 2020)

Summary

Introduction

Porcine reproductive and respiratory syndrome (PRRS) appeared in Europe and the United States in the 1990s and became a problem that plagued the global pig industry ever since. Lineage 1 PRRSV contains representative strains, such as NADC30, JL580, NADC34, and RFLP 1-4-4. Lineage 3 PRRSV is mainly prevalent in South China and has low pathogenicity, including representative strains such as QYYZ and GM2. Lineage 5 mainly contains the classical PRRSV strain represented by VR2332. The NADC30-like strain in lineage 1 appeared in the United States in 2008 and in China in 2013. Pigs infected with NADC30-like PRRSV strain after vaccination still have obvious clinical symptoms, high viremia, and virus load in various tissues (Bai et al, 2016; Zhou et al, 2017; Wei et al, 2019; Chen et al, 2021). The development of a PRRSV vaccine against NADC30-like PRRSV is important to combat the continuously increasing epidemic of NADC30like PRRS outbreaks

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