Characteristics and Pathogenicity of the Cell-Adapted Attenuated Porcine Epidemic Diarrhea Virus of the Non-S INDEL Cluster

The high antigenic diversity of porcine epidemic diarrhea virus (PEDV) means that porcine epidemic diarrhea (PED) is a challenge for the global pig industry. Understanding the circulation of the virus to determine an optimal vaccine strategy is important in controlling the disease. In this study, we describe the genetic diversity of circulating PEDV based on the full sequences of spike genes of eight positive samples collected in Vietnam since 2018. Additionally, we developed a live attenuated vaccine candidate from the cell-adapted PEDV2 strain, which was continuously passaged until level 103 in VERO-CCL81 cells. PEDV2-p103, which belongs to the emerging non-S INDEL cluster, exhibited low virus shedding, did not induce lesions in the small intestine of challenged piglets, and had a high titer in the VERO-CCL81 cell at 48 h post-infection. These results suggest that the PEDV2-p103 strain could be a potential oral attenuated vaccine, and its immunogenicity and efficacy should be further assessed through in vivo tests.

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Emergence and evolution of highly pathogenic porcine epidemic diarrhea virus by natural recombination of a low pathogenic vaccine isolate and a highly pathogenic strain in the spike gene

Virus Evolution ◽

10.1093/ve/veaa049 ◽

2020 ◽

Vol 6 (2) ◽

Author(s):

Huinan Wang ◽

Libo Zhang ◽

Yuanbin Shang ◽

Rongrong Tan ◽

Mingxiang Ji ◽

...

Keyword(s):

Porcine Epidemic Diarrhea Virus ◽

Intestinal Epithelial ◽

Orf3 Gene ◽

Highly Pathogenic ◽

Spike Gene ◽

Diarrhea Virus ◽

Attenuated Vaccine ◽

New Variant ◽

Porcine Epidemic Diarrhea ◽

Natural Recombination

Abstract Outbreaks of a new variant of porcine epidemic diarrhea virus (PEDV) at the end of 2010 have raised interest in the mutation and recombination of PEDV. A PEDV strain (CN/Liaoning25/2018) isolated from a clinical outbreak of piglet diarrhea contained a 49-bp deletion in the ORF3 gene. This deletion is considered a genetic characteristic of low pathogenic attenuated vaccine strains. However, CN/Liaoning25/2018 was highly pathogenic. Complete genome sequencing, identity analysis, phylogenetic tree construction, and recombination analysis showed that this virus was a recombinant strain containing the Spike (S) gene from the highly pathogenic CN/GDZQ/2014 strain and the remaining genomic regions from the low pathogenic vaccine isolate SQ2014. Histopathology and immunohistochemistry results confirmed that this strain was highly pathogenic and indicated that intestinal epithelial cell vacuolation was positively correlated with the intensity and density of PEDV antigens. A new natural recombination model for PEDV was identified. Our results suggest that new highly pathogenic recombinant strains in the field may be generated by recombination between low pathogenic attenuated live PEDV vaccines and pathogenic circulating PEDV strains. Our findings also highlight that the 49-bp deletion of the ORF3 gene in low pathogenic attenuated vaccine strains will no longer be a reliable standard to differentiate the classical vaccine attenuated from the field strains.

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Porcine Intestinal Enteroids: a New Model for Studying Enteric Coronavirus Porcine Epidemic Diarrhea Virus Infection and the Host Innate Response

Journal of Virology ◽

10.1128/jvi.01682-18 ◽

2018 ◽

Vol 93 (5) ◽

Cited By ~ 12

Author(s):

Liang Li ◽

Fang Fu ◽

Shanshan Guo ◽

Hongfeng Wang ◽

Xijun He ◽

...

Keyword(s):

Stem Cells ◽

Intestinal Epithelium ◽

Porcine Epidemic Diarrhea Virus ◽

Enteric Viruses ◽

Antiviral Response ◽

Diarrhea Virus ◽

Porcine Epidemic Diarrhea ◽

Ifn Lambda

ABSTRACTPorcine epidemic diarrhea virus (PEDV), a member of the group of alphacoronaviruses, is the pathogen of a highly contagious gastrointestinal swine disease. The elucidation of the events associated with the intestinal epithelial response to PEDV infection has been limited by the absence of goodin vitroporcine intestinal models that recapitulate the multicellular complexity of the gastrointestinal tract. Here, we generated swine enteroids from the intestinal crypt stem cells of the duodenum, jejunum, or ileum and found that the generated enteroids are able to satisfactorily recapitulate the complicated intestinal epitheliumin vivoand are susceptible to infection by PEDV. PEDV infected multiple types of cells, including enterocytes, stem cells, and goblet cells, and exhibited segmental infection discrepancies compared with ileal enteroids and colonoids, and this finding was verifiedin vivo. Moreover, the clinical isolate PEDV-JMS propagated better in ileal enteroids than the cell-adapted isolate PEDV-CV777, and PEDV infection suppressed interferon (IFN) production early during the infection course. IFN lambda elicited a potent antiviral response and inhibited PEDV in enteroids more efficiently than IFN alpha (IFN-α). Therefore, swine enteroids provide a novelin vitromodel for exploring the pathogenesis of PEDV and for thein vitrostudy of the interplay between a host and a variety of swine enteric viruses.IMPORTANCEPEDV is a highly contagious enteric coronavirus that causes significant economic losses, and the lack of a goodin vitromodel system is a major roadblock to an in-depth understanding of PEDV pathogenesis. Here, we generated a porcine intestinal enteroid model for PEDV infection. Utilizing porcine intestinal enteroids, we demonstrated that PEDV infects multiple lineages of the intestinal epithelium and preferably infects ileal enteroids over colonoids and that enteroids prefer to respond to IFN lambda 1 over IFN-α. These events recapitulate the events that occurin vivo. This study constitutes the first use of a primary intestinal enteroid model to investigate the susceptibility of porcine enteroids to PEDV and to determine the antiviral response following infection. Our study provides important insights into the events associated with PEDV infection of the porcine intestine and provides a valuablein vitromodel for studying not only PEDV but also other swine enteric viruses.

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Oral Delivery of Probiotics Expressing Dendritic Cell-Targeting Peptide Fused with Porcine Epidemic Diarrhea Virus COE Antigen: A Promising Vaccine Strategy against PEDV

Viruses ◽

10.3390/v9110312 ◽

2017 ◽

Vol 9 (11) ◽

pp. 312 ◽

Cited By ~ 28

Author(s):

Xiaona Wang ◽

Li Wang ◽

Xuewei Huang ◽

Sunting Ma ◽

Meiling Yu ◽

...

Keyword(s):

Dendritic Cell ◽

Porcine Epidemic Diarrhea Virus ◽

Oral Delivery ◽

Cell Targeting ◽

Vaccine Strategy ◽

Diarrhea Virus ◽

Porcine Epidemic Diarrhea ◽

Antigen A ◽

Targeting Peptide

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Genome Sequences of Porcine Epidemic Diarrhea Virus: In Vivo and In Vitro Phenotypes

Genome Announcements ◽

10.1128/genomea.00503-14 ◽

2014 ◽

Vol 2 (3) ◽

Cited By ~ 8

Author(s):

P. K. Lawrence ◽

E. Bumgardner ◽

R. F. Bey ◽

D. Stine ◽

R. E. Bumgarner

Keyword(s):

Porcine Epidemic Diarrhea Virus ◽

Genome Sequences ◽

Diarrhea Virus ◽

Porcine Epidemic Diarrhea

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Successive Passage In Vitro Led to Lower Virulence and Higher Titer of A Variant Porcine Epidemic Diarrhea Virus

Viruses ◽

10.3390/v12040391 ◽

2020 ◽

Vol 12 (4) ◽

pp. 391 ◽

Cited By ~ 1

Author(s):

Pengwei Zhao ◽

Song Wang ◽

Zhi Chen ◽

Jiang Yu ◽

Rongzhi Tang ◽

...

Keyword(s):

Amino Acids ◽

Porcine Epidemic Diarrhea Virus ◽

Vero Cells ◽

Economic Losses ◽

Diarrhea Virus ◽

S Gene ◽

Successive Passage ◽

Porcine Epidemic Diarrhea

A highly virulent porcine epidemic diarrhea virus (PEDV) appeared in China and spread rapidly to neighbor countries, which have led to great economic losses to the pig industry. In the present study, we isolated a PEDV using Vero cells and serially propagated 100 passages. PEDV SDSX16 was characterized in vitro and in vivo. The viral titers increased to 107.6 TCID50/mL (100th) by serial passages. The spike (S) gene and the whole gene of the SDSX16 virus was fully sequenced to assess the genetic stability and relatedness to previously identified PEDV. Along with successive passage in vitro, there were 18 nucleotides (nt) deletion occurred in the spike (S) gene resulting in a deletion of six amino acids when the SDSX16 strain was passaged to the 64th generation, and this deletion was stable until the P100. However, the ORF1a/b, M, N, E, and ORF3 genes had only a few point mutations in amino acids and no deletions. According to growth kinetics experiments, the SDSX16 deletion strain significantly enhanced its replication in Vero cells since it was passaged to the 64th generation. The animal studies showed that PEDV SDSX16-P10 caused more severe diarrhea and vomiting, fecal shedding, and acute atrophic enteritis than SDSX16-P75, indicating that SDSX16-P10 is enteropathogenic in the natural host, and the pathogenicity of SDSX16 decreased with successive passage in vitro. However, SDSX16-P10 was found to cause lower levels of cytokine expression than SDSX16-P75 using real-time PCR and flow cytometry, such as IL1β, IL6, IFN-β, TNF-α, indicating that SDSX16-P10 might inhibit the expression of cytokines. Our data indicated that successive passage in vitro resulted in virulent attenuation in vivo of the PEDV variant strain SDSX16.

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A TaqMan probe-based real-time PCR to differentiate porcine epidemic diarrhea virus virulent strains from attenuated vaccine strains

Molecular and Cellular Probes ◽

10.1016/j.mcp.2019.04.003 ◽

2019 ◽

Vol 45 ◽

pp. 37-42 ◽

Cited By ~ 5

Author(s):

Jing Liu ◽

Li-min Li ◽

Jiu-qaun Han ◽

Tai-ran Sun ◽

Xue Zhao ◽

...

Keyword(s):

Real Time ◽

Real Time Pcr ◽

Porcine Epidemic Diarrhea Virus ◽

Taqman Probe ◽

Diarrhea Virus ◽

Attenuated Vaccine ◽

Virulent Strains ◽

Porcine Epidemic Diarrhea

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Crystallization and preliminary crystallographic study ofPorcine epidemic diarrhea virusmain protease in complex with an inhibitor

Acta Crystallographica Section F Structural Biology Communications ◽

10.1107/s2053230x14021876 ◽

2014 ◽

Vol 70 (12) ◽

pp. 1608-1611

Author(s):

Yusheng Tan ◽

Fenghua Wang ◽

Xia Chen ◽

Jinshan Wang ◽

Qi Zhao ◽

...

Keyword(s):

Porcine Epidemic Diarrhea Virus ◽

Antiviral Drug ◽

Proteolytic Processing ◽

Genome Replication ◽

Virus Shedding ◽

Cell Parameters ◽

Diarrhea Virus ◽

Main Protease ◽

Porcine Epidemic Diarrhea ◽

Complex Crystals

Porcine epidemic diarrhea virus(PEDV) mainly infects neonatal pigs, resulting in significant morbidity and mortality. Owing to problems such as long periods of virus shedding, existing vaccines cannot provide complete protection from PEDV infection. The PEDV genome encodes two polyprotein precursors required for genome replication and transcription. Each polyprotein undergoes extensive proteolytic processing, resulting in functional subunits. This process is mainly mediated by its genome-encoded main protease, which is an attractive target for antiviral drug design. In this study, the main protease ofPorcine epidemic diarrhea virusin complex with a Michael acceptor was crystallized. The complex crystals diffracted to 2.5 Å resolution and belonged to space groupR3, with unit-cell parametersa= 175.3,b= 175.3,c= 58.7 Å. Two molecules were identified per asymmetric unit.

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