The spike glycoprotein genes of porcine epidemic diarrhea viruses isolated in China

AbstractThe porcine epidemic diarrhea virus (PEDV) causes a highly contagious disease in pigs, which is one of the most devastating viral diseases of swine in the world. In China, PEDV was first confirmed in 1984 and PEDV infections occurred sporadically from 1984 to early 2010. From late 2010 until present, PEDV infections have swept every province or region in China. In this study, we analyzed a total of 186 full-length spike genes and deduced proteins of all available complete genomes of PEDVs isolated in China during 2007–2019. A total of 28 potential recombination events were identified in the spike genes of PEDVs in China. Spike gene recombination not only expanded the genetic diversity of PEDVs in the GII genogroup, but also resulted in the emergence of a new evolutional branch GI-c during 2016–2018. In addition, comparative analysis of spike proteins between GI-a prototype virulent CV777 and GII strain AJ1102 reveals that the amino acid variations could affect 20 potential linear B cell epitopes, demonstrating a dramatic antigen drift in the spike protein. These results provide a thorough view of the information about the genetic and antigenic diversity of PEDVs circulating in China and therefore could benefit the development of suitable strategies for disease control.

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Identification of two novel B cell epitopes on porcine epidemic diarrhea virus spike protein

Veterinary Microbiology ◽

10.1016/j.vetmic.2008.02.022 ◽

2008 ◽

Vol 131 (1-2) ◽

pp. 73-81 ◽

Cited By ~ 109

Author(s):

Dongbo Sun ◽

Li Feng ◽

Hongyan Shi ◽

Jianfei Chen ◽

Xiaochen Cui ◽

...

Keyword(s):

B Cell ◽

Porcine Epidemic Diarrhea Virus ◽

Spike Protein ◽

B Cell Epitopes ◽

Diarrhea Virus ◽

Porcine Epidemic Diarrhea

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N-terminal Domain of the Spike Protein of Porcine Epidemic Diarrhea Virus as a New Candidate Molecule for a Mucosal Vaccine

Immune Network ◽

10.4110/in.2018.18.e21 ◽

2018 ◽

Vol 18 (3) ◽

Cited By ~ 4

Author(s):

Sae-Hae Kim ◽

Byeol-Hee Cho ◽

Kyung-Yeol Lee ◽

Yong-Suk Jang

Keyword(s):

Porcine Epidemic Diarrhea Virus ◽

Mucosal Vaccine ◽

Spike Protein ◽

Diarrhea Virus ◽

Terminal Domain ◽

Porcine Epidemic Diarrhea ◽

Candidate Molecule

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Immunodominant and neutralizing linear B cell epitopes spanning the spike and membrane proteins of Porcine Epidemic Diarrhea Virus

10.1101/2021.10.05.463270 ◽

2021 ◽

Author(s):

Kanokporn Polyiam ◽

Marasri Ruengjitchatchawalya ◽

Phenjun Mekvichitsaeng ◽

Kampon Kaeoket ◽

Tawatchai Hoonsuwan ◽

...

Keyword(s):

B Cell ◽

Porcine Epidemic Diarrhea Virus ◽

M Protein ◽

B Cell Epitopes ◽

Diarrhea Virus ◽

M Proteins ◽

Porcine Epidemic Diarrhea ◽

Neutralizing Epitopes ◽

Immunodominant Epitopes ◽

Linear B

AbstractPorcine Epidemic Diarrhea Virus (PEDV) is the causative agent of PED, an enteric disease that causes high mortality rates in piglets. PEDV is an alphacoronavirus that has high genetic diversity. Insights into neutralizing B cell epitopes of all genetically diverse PEDV strains are of importance, particularly for designing a vaccine that can provide broad protection against PEDV. In this work, we aimed to explore the landscape of linear B cell epitopes on the spike (S) and membrane (M) proteins of global PEDV strains. All amino acid sequences of the PEDV S and M proteins were retrieved from the NCBI database and grouped. Immunoinformatics-based methods were next developed and used to identify putative linear B cell epitopes from 14 and 5 consensus sequences generated from distinct groups of the S and M proteins, respectively. ELISA testing predicted peptides with PEDV-positive sera revealed 9 novel immunodominant epitopes on the S protein. Importantly, 7 of these novel immunodominant epitopes and other subdominant epitopes were demonstrated to be neutralizing epitopes by neutralization-inhibition assay. Additionally, our study shows the first time that M protein is also the target of neutralizing antibodies as 7 neutralizing epitopes in the M protein were identified. Conservancy analysis revealed that epitopes in the S1 subunit are more variable than those in the S2 subunit and M protein. In this study, we offer the immunoinformatics approach for linear B cell epitope identification and a more complete profile of linear B cell epitopes across the PEDV S and M proteins, which may contribute to the development of a greater PEDV vaccine as well as peptide-based immunoassays.

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Engineering a Live Attenuated Porcine Epidemic Diarrhea Virus Vaccine Candidate via Inactivation of the Viral 2'-O-Methyltransferase and the Endocytosis Signal of the Spike Protein

Journal of Virology ◽

10.1128/jvi.00406-19 ◽

2019 ◽

Vol 93 (15) ◽

Cited By ~ 10

Author(s):

Yixuan Hou ◽

Hanzhong Ke ◽

Jineui Kim ◽

Dongwan Yoo ◽

Yunfang Su ◽

...

Keyword(s):

Porcine Epidemic Diarrhea Virus ◽

Vaccine Development ◽

Vaccine Candidate ◽

Spike Protein ◽

Economic Losses ◽

High Dose ◽

Type I ◽

Viral Pathogen ◽

Diarrhea Virus ◽

Porcine Epidemic Diarrhea

ABSTRACT Porcine epidemic diarrhea virus (PEDV) causes high mortality in neonatal piglets; however, effective and safe vaccines are still not available. We hypothesized that inactivation of the 2′-O-methyltransferase (2′-O-MTase) activity of nsp16 and the endocytosis signal of the spike protein attenuates PEDV yet retains its immunogenicity in pigs. We generated a recombinant PEDV, KDKE4A, with quadruple alanine substitutions in the catalytic tetrad of the 2′-O-MTase using a virulent infectious cDNA clone, icPC22A, as the backbone. Next, we constructed another mutant, KDKE4A-SYA, by abolishing the endocytosis signal of the spike protein of KDKE4A. Compared with icPC22A, the KDKE4A and KDKE4A-SYA mutants replicated less efficiently in vitro but induced stronger type I and type III interferon responses. The pathogenesis and immunogenicities of the mutants were evaluated in gnotobiotic piglets. The virulence of KDKE4A-SYA and KDKE4A was significantly reduced compared with that of icPC22A. Mortality rates were 100%, 17%, and 0% in the icPC22A-, KDKE4A-, and KDKE4A-SYA-inoculated groups, respectively. At 21 days postinoculation (dpi), all surviving pigs were challenged orally with a high dose of icPC22A. The KDKE4A-SYA- and KDKE4A-inoculated pigs were protected from the challenge, because no KDKE4A-SYA- and one KDKE4A-inoculated pig developed diarrhea whereas all the pigs in the mock-inoculated group had severe diarrhea, and 33% of them died. Furthermore, we serially passaged the KDKE4A-SYA mutant in pigs three times and did not find any reversion of the introduced mutations. The data suggest that KDKE4A-SYA may be a PEDV vaccine candidate. IMPORTANCE PEDV is the most economically important porcine enteric viral pathogen and has caused immense economic losses in the pork industries in many countries. Effective and safe vaccines are desperately required but still not available. 2′-O-MTase (nsp16) is highly conserved among coronaviruses (CoVs), and the inactivation of nsp16 in live attenuated vaccines has been attempted for several betacoronaviruses. We show that inactivation of both 2′-O-MTase and the endocytosis signal of the spike protein is an approach to designing a promising live attenuated vaccine for PEDV. The in vivo passaging data also validated the stability of the KDKE4A-SYA mutant. KDKE4A-SYA warrants further evaluation in sows and their piglets and may be used as a platform for further optimization. Our findings further confirmed that nsp16 can be a universal target for CoV vaccine development and will aid in the development of vaccines against other emerging CoVs.

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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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