Development of the full-length cDNA clones of two porcine epidemic diarrhea disease virus isolates with different virulence

PLoS One. 2017 Mar 16;12(3):e0173998. doi: 10.1371/journal.pone.0173998. eCollection 2017.

Abstract

The recently emerged highly virulent variants of porcine epidemic and diarrhea virus (PEDV) remain a huge threat to the worldwide swine industry. Here, we describe the development of a bacterial artificial chromosome (BAC) reverse genetics system for PEDV based on two recent Chinese field isolates, namely CHM2013 and BJ2011C. Phylogenetically, CHM2013 is closely related to the vaccine strain SM98 whereas the isolate BJ2011C belongs to the GIIb group, a cluster that contains many recent pandemic strains. The full-length cDNA clones of the two isolates were constructed into BAC under the control of CMV promoter. The rescued viruses rBJ2011C and rCHM2013 were found to replicate at the kinetics similar to their respective parental viruses in cell culture. When tested in the 2-day-old pig model, rBJ2011C caused severe diarrhea of piglets with extensive damages to the intestinal epithelium, leading to 100% fatality within 48 hours. In contrast, the rCHM2013-inoculated piglets all survived with only very minor tissue damage observed. Thus, we have successfully established a convenient platform for PEDV genome manipulation. This study also represents the first description of a DNA-launched reverse genetics system for the highly virulent PEDV.

MeSH terms

  • Animals
  • Chlorocebus aethiops
  • Cloning, Molecular
  • DNA, Complementary / genetics*
  • Phylogeny
  • Porcine epidemic diarrhea virus / classification
  • Porcine epidemic diarrhea virus / genetics*
  • Porcine epidemic diarrhea virus / pathogenicity
  • Promoter Regions, Genetic
  • Swine
  • Vero Cells
  • Virulence

Substances

  • DNA, Complementary

Grants and funding

This work was supported by the National Key Research and Development Program (2016YFD0500101) (http://program.most.gov.cn/) and the earmarked fund for Modern Agro-industry Technology Research System of China (CARS-36) from the Chinese Ministry of Agriculture (http://www.moa.gov.cn/).