company news about [Latest Research] A Comprehensive Analysis of Molecular Characteristics and Antigenic Epitopes of Porcine Epidemic Diarr

On October 8, 2025, a research team from the Institute of Zoonoses at Jilin University and the Xinjiang Research Group published a new study on porcine epidemic diarrhea virus (PEDV) in *Frontiers in Veterinary Science*, systematically revealing the epidemic trend, molecular characteristics, and antigenic epitope changes of PEDV in China from 2022 to 2025.

Research Highlights

* Covering 20 provinces across China, a total of 2346 samples were tested, with a PEDV positivity rate of 43.3%.

* Genotyping showed that G2c has become the current mainstream subtype.

* Multiple mutations were found in key neutralizing epitopes of the S protein (COE, SS2, SS6, 2C10).

* A new potential N-glycosylation site (position 302) was discovered for the first time in the Xinjiang strain.

* Seven linear and two conformational antigenic epitopes were predicted, providing new targets for vaccine development.

This study indicates that compared to the classic vaccine strain CV777, the current circulating strain shares only 92.71%-94.99% nucleotide and amino acid similarity in the S protein, suggesting that the protective efficacy of existing vaccines may be weakening. Continuous mutation of the virus in key antigenic regions may exacerbate immune escape.

Introduction

PEDV is a significant coronavirus threatening the global swine industry, causing diarrhea, vomiting, and dehydration in pigs of all ages, with extremely high mortality rates in suckling piglets. Since the emergence of highly pathogenic variants in 2010, China's epidemic prevention and control has faced continuous challenges.

This latest research, completed by Professor Mo Xiaobing and Researcher Li Tianzeng's team at Jilin University in collaboration with a research team in Xinjiang, boasts a large sample size, broad coverage, and in-depth mechanistic analysis. It represents a significant achievement in the field of PEDV research by 2025 and possesses high academic credibility.

Research Results

1. Epidemiological Trends:

The overall PEDV positivity rate in China from 2022 to 2025 was 43.3%, with six provinces including Liaoning, Anhui, and Guangxi having positivity rates exceeding 60%. Xinjiang, South China, and Northeast China were high-incidence areas.

Figure 1. Porcine epidemic diarrhea virus (PEDV) infection and its geographical distribution in patients who died from diarrhea.

(A) Bar graph shows the PEDV positivity rate in each province, and line graph shows the upper and lower limits of the 95% confidence interval. (B) Geographical distribution of PEDV. Colors from green to red indicate an increasing positivity rate.

2. Genotypic characteristics:

Of the 15 sequenced strains, 1 was of the G1c subtype, 4 were of the G2b subtype, and 10 were of the G2c subtype, confirming that G2c has become the dominant subtype.

Figure 2. Phylogenetic tree of the PEDV S gene

Red pentagrams represent sequences obtained in this study. Different colors represent different genotypes.

3. Sequence variation:

The nucleotide and amino acid homology of the S gene of the sequenced strain and the classic vaccine strain CV777 were only 92.71%-94.83% and 92.89%-94.99%, respectively. Different degrees of mutations were observed in key neutralizing epitopes (COE, SS2, SS6, 2C10).

Figure 3. Comparison of key antigenic epitopes of PEDV S protein

The green, orange, blue, and yellow regions correspond to the antigenic epitopes COE, SS2, SS6, and 2C10, respectively.

4. Antigenic epitopes and glycosylation characteristics:

Seven conserved antigenic regions, including 31-54aa, were predicted. A novel N-glycosylation site at position 302 (NKTI) was found in the PEDV/XinJiang/2 strain. The absence of glycosylation sites in some strains may be related to immune escape.

Figure 4. Prediction results of potential specific N-glycosylation sites in the S protein of 15 PEDV strains and vaccine strains.

The vertical axis represents the strain name, and the horizontal axis represents the amino acid site. Blue areas indicate identical N-glycosylation at the same amino acid site, and red areas indicate differences.

Figure 5. Visualization of conserved regions of continuous epitopes in the native trimer state of the S protein.

(A) Amino acid sequence alignment of the sequenced strain and vaccine strain in the predicted epitope region. (B–E) Visualization of conserved antigenic epitopes. Blue, green, and white regions represent chains A, B, and C of the S protein trimer, respectively. Yellow spheres indicate potential antigenic epitope regions with scores greater than 0.7. (F) Enlarged view of key amino acid sites on the S protein monomer, where red areas represent key amino acid sites on the S protein monomer.

Figure 6. Visualization of conserved regions of continuous epitopes in the native trimer state of the S protein.

(A) Amino acid sequence alignment of sequenced and vaccine strains in predicted epitope regions. (B–E) Visualization of conserved antigenic epitopes. Blue, green, and white regions represent chains A, B, and C of the S protein trimer, respectively. Yellow spheres indicate potential antigenic epitope regions with scores greater than 0.7. (F) Enlarged view of key amino acid sites on the S protein monomer, with red areas representing key amino acid sites on the S protein monomer.

Summary

This study not only updated the molecular epidemiological map of PEDV in China from 2022 to 2025, but also revealed the variation trends of key antigenic epitopes and immune escape mechanisms.

The results indicate that existing vaccine strains (such as CV777) differ significantly from circulating strains, suggesting the need to develop next-generation vaccines based on the G2c genotype to address the challenges of prevention and control posed by the continuous evolution of the virus.