Chimeric HP-PRRSV2 containing an ORF2-6 consensus sequence induces antibodies with broadly neutralizing activity and confers cross protection against virulent NADC30-like isolate

Abstract

Due to the substantial genetic diversity of porcine reproductive and respiratory syndrome virus (PRRSV), commercial PRRS vaccines fail to provide sufficient cross protection. Previous studies have confirmed the existence of PRRSV broadly neutralizing antibodies (bnAbs). However, bnAbs are rarely induced by either natural infection or vaccination. In this study, we designed and synthesized a consensus sequence of PRRSV2 ORF2-6 genes (ORF2-6-CON) encoding all envelope proteins based on 30 representative Chinese PRRSV isolates. The ORF2-6-CON sequence shared > 90% nucleotide identities to all four lineages of PRRSV2 isolates in China. A chimeric virus (rJS-ORF2-6-CON) containing the ORF2-6-CON was generated using the avirulent HP-PRRSV2 JSTZ1712-12 infectious clone as a backbone. The rJS-ORF2-6-CON has similar replication efficiency as the backbone virus in vitro. Furthermore, pig inoculation and challenge studies showed that rJS-ORF2-6-CON is not pathogenic to piglets and confers better cross protection against the virulent NADC30-like isolate than a commercial HP-PRRS modified live virus (MLV) vaccine. Noticeably, the rJS-ORF2-6-CON strain could induce bnAbs while the MLV strain only induced homologous nAbs. In addition, the lineages of VDJ repertoires potentially associated with distinct nAbs were also characterized. Overall, our results demonstrate that rJS-ORF2-6-CON is a promising candidate for the development of a PRRS genetic engineered vaccine conferring cross protection.

Systemic Homologous Neutralizing Antibodies Are Inadequate for the Evaluation of Vaccine Protective Efficacy against Coinfection by High Virulent PEDV and PRRSV

“…Viruses used in this study were all stored in our laboratories, including G2 PEDV XM1-2 strain ( KX812523 ) ( 2 ), YC2014 isolate ( KU252649 ) ( 48 ), XJ1904-34 virus ( OK642747 ), rPEDV-EGFP infectious clone and G1 CV777 strain, PRRSV2 CH-1a-like SD1612-1 isolate, VR2332-like JSYC20-05-1 isolate, NADC30-like SD17-36 isolate, HP-PRRSV2 XJ17-5 and JSTZ1712-12 strains, rJSTZ1712-12 and rXJ17-5-dsRed infectious clones ( 3 , 49 – 51 ), and PRRSV1 HLJB1 isolate ( 52 ). Vero cell, Marc-145 cells, and BHK-21 cells were cultured in Dulbecco minimum essential median (DMEM) supplemented with 10% fetal bovine serum (FBS) and antibiotics.…”

“…To construct a chimeric virus expressing S protein of G2 PEDV, the previously developed HP-PRRSV2 infectious clone rJSTZ1712-12 was used as the backbone ( 3 ). At first, the S gene of G2 PEDV was amplified from the currently prevalent XJ1904-34 strain using high fidelity 2 × Phanta Flash Master Mix (Vazyme Biotech Co., Ltd., China) with primers shown in Table 1 .…”

“…Porcine epidemic diarrhea (PED) is a highly contagious enteric disease principally causing diarrhea, vomiting, dehydration, and high mortality in suckling piglets, while porcine reproductive and respiratory syndrome (PRRS) is another highly contagious disease characterized by reproductive failure in sows and respiratory disease in all ages of pigs ( 1 – 3 ). In China, PED was first confirmed in 1984 and PRRS was first reported in 1995 ( 4 , 5 ).…”

“…For instance, chimeric transmissible gastroenteritis virus (TGEV) and vesicular stomatitis virus (VSV) expressing S protein of G2 PEDV could induce shnAbs and provide protection against virulent G2 PEDV challenge ( 8 , 27 ). In addition, chimeric PRRSV strains containing mixed ORF5-6 genes, shuffled ORF3-6 genes, or consensus ORF2-6 sequence could even induce heterologous snAbs and conferred cross-protection against heterologous PRRSV strains ( 3 , 28 , 29 ). However, whether PEDV and PRRSV shnAbs could confer dual protection against the widely prevalent highly pathogenic G2 PEDV and HP-PRRSV2 isolates in China has not been described yet.…”

A Systematic Investigation Unveils High Coinfection Status of Porcine Parvovirus Types 1 through 7 in China from 2016 to 2020

“…To prepare the standard positive control, seven amplicons from the panel of PCR assays were combined as a standard gene for synthesis (Genewiz, Suzhou, China) as we described previously ( 43 ). The synthetic sequence was cloned into the pUC57 vector and transformed into DH5α chemically competent cells.…”