Evaluation on the efficacy and immunogenicity of recombinant DNA plasmids expressing S gene from porcine epidemic diarrhea virus and VP7 gene from porcine rotavirus

Tris stabilized AuNPs based lateral flow immunochromatography for the simultaneous detection of porcine epidemic diarrhea virus and rotavirus on-site

Porcine epidemic diarrhea virus (PEDV) and rotavirus has posed a significant threat to the pig industry annually across different nations, resulting in huge economic losses. The frequent co-infection of these two viruses in clinical settings complicates the process of differential diagnoses. Rapid and accurate detection of PEDV and rotavirus is in great demand for timely diarrhea disease prevention and control. In this study, tris stabilized AuNPs were prepared and a sensitive lateral flow immunoassay (LFIA) sensor was developed for the simultaneous and rapid detection of PEDV and rotavirus on site. After the system optimization, the established LFIA can simultaneously identify PEDV and rotavirus with limits of detection (LOD) of 1.25 × 103 TCID50 mL-1 and 3.13 × 102 pg mL-1, respectively. When applying for clinical samples, the LFIA show a concordance of 95 % and 100 % to reverse transcript polymerase chain reaction (RT-PCR) for PEDV and rotavirus respectively. Therefore, this LFIA can qualitatively detect PEDV and rotavirus in 18 min with high sensitivity and accuracy without any sophisticated equipment and operation, making it a promising candidate for the early diagnosis of PEDV or/and rotavirus diarrhea on site.

High-affinity monoclonal antibodies against the porcine epidemic diarrhea virus S1 protein

The porcine epidemic diarrhea virus (PEDV) infection inflicted substantial economic losses upon the global pig-breeding industry. This pathogen can infect all pigs and poses a particularly high fatality risk for suckling piglets. The S1 subunit of spike protein is a crucial target protein for inducing the particularly neutralizing antibodies that can intercept the virus-host interaction and neutralize virus infectivity. In the present study, the HEK293F eukaryotic expression system was successfully utilized to express and produce recombinant S1 protein. Through quantitative analysis, five monoclonal antibodies (mAbs) specifically targeting the recombinant S1 protein of PEDV were developed and subsequently evaluated using enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence assay (IFA), and flow cytometry assay (FCA). The results indicate that all five mAbs belong to the IgG1 isotype, and their half-maximal effective concentration (EC50) values measured at 84.77, 7.42, 0.89, 14.64, and 7.86 pM. All these five mAbs can be utilized in ELISA, FCA, and IFA for the detection of PEDV infection. MAb 5-F9 exhibits the highest sensitivity to detect as low as 0.3125 ng/mL of recombinant PEDV-S1 protein in ELISA, while only 0.096 ng/mL of mAb 5-F9 is required to detect PEDV in FCA. The results from antigen epitope analysis indicated that mAb 8-G2 is the sole antibody capable of recognizing linear epitopes. In conclusion, this study has yielded a highly immunogenic S1 protein and five high-affinity mAbs specifically targeting the S1 protein. These findings have significant implications for early detection of PEDV infection and provide a solid foundation for further investigation into studying virus-host interactions.

Research progress of porcine epidemic diarrhea virus S protein

Porcine epidemic diarrhea virus (PEDV) is a single-stranded RNA virus with a capsid membrane that causes acute infectious gastrointestinal disease characterized by vomiting, diarrhea, and dehydration in swine. Piglets are more susceptible to PEDV than adults, with an infection rate reaching 90% and a fatality rate as high as 100%. Moreover, PEDV has a rapid transmission rate and broad transmission range. Consequently, PEDV has caused considerable economic losses and negatively impacted the sustainability of the pig industry. The surface spike (S) glycoprotein is the largest structural protein in PEDV virions and is closely associated with host cell fusion and virus invasion. As such, the S protein is an important target for vaccine development. In this article, we review the genetic variation, immunity, apoptosis-induction function, virulence, vaccine potential, and other aspects of the PEDV S protein. This review provides a theoretical foundation for preventing and controlling PEDV infection and serves as a valuable resource for further research and development of PEDV vaccines.

Overview of the recent advances in porcine epidemic diarrhea vaccines

Vaccination is the most effective means of preventing and controlling porcine epidemic diarrhea (PED). Conventional vaccines developed from porcine epidemic diarrhea virus (PEDV) GI-a subtypes (CV777 and SM98) have played a vital role in preventing classical PED. However, with the emergence of PEDV mutants in 2010, conventional PEDV GI-a subtype-targeting vaccines no longer provide adequate protection against PEDV GII mutants, thereby making novel-type PED vaccine development an urgent concern to be addressed. Novel vaccines, including nucleic acid vaccines, genetically engineered subunit vaccines, and live vector vaccines, are associated with several advantages, such as high safety and stability, clear targeting, high yield, low cost, and convenient usage. These vaccines can be combined with corresponding ELISA kits to differentiate infected from vaccinated animals, which is beneficial for disease confirmation. This review provides a detailed overview of the recent advancements in PED vaccines, emphasizing on the research and application evaluation of novel PED vaccines. It also considers the future directions and challenges in advancing these vaccines to widespread use in clinics.

Porcine Epidemic Diarrhea: Insights and Progress on Vaccines

Porcine epidemic diarrhea (PED) is a swine-wasting disease caused by coronavirus infection. It causes great economic damage to the swine industry worldwide. Despite the continued use of vaccines, PED outbreaks continue, highlighting the need to review the effectiveness of current vaccines and develop additional vaccines based on new platforms. Here, we review existing vaccine technologies for preventing PED and highlight promising technologies that may help control PED virus in the future.

Vector-delivered artificial miRNA effectively inhibits Porcine epidemic diarrhea virus replication

BACKGROUND

Porcine epidemic diarrhea virus (PEDV) is an α-coronavirus that causes highly contagious intestinal infectious disease, involving clinically characterized by diarrhea, dehydration, vomiting, and high mortality to suckling piglets. As a strategy for antiviral therapy, artificial microRNA (amiRNA) mediated suppression of viral replication has recently become increasingly important. In this study, we evaluated the advantages of using an amiRNA vector against PEDV.

METHODS

In this study, we evaluated the advantages of using an amiRNA vector against PEDV. We designed two single amiRNA sequences for different conserved sequences of the PEDV S and N genes, and tested their inhibitory effects on PEDV in Vero cells.

RESULTS

It was obvious from the CCK-8 results that the transient transfection of amiRNA was non-toxic to the cells. In addition, our results showed that the transient expression of two amiRNAs (amiRNA-349 and amiRNA-1447) significantly reduced the expression of viral RNA and protein in the cells. The TCID₅₀ results showed that the release of virus particles into the culture supernatant was significantly reduced, with an effect as high as 90%. To avoid virus mutation escape, the above two single amiRNA sequences were tandem in this study (amiRNA-349 + 1447), enabling a single microRNA to be expressed simultaneously. The real-time PCR and Western blot results showed that the inhibitory effect was significantly enhanced in each of the different time periods. The TCID₅₀ results showed that the release of virus particles in the culture supernatant was significantly reduced at the different time periods.

CONCLUSIONS

In summary, these results suggest that an RNAi based on amiRNA targeting the conserved region of the virus is an effective method to improve PEDV nucleic acid inhibitors and provide a novel treatment strategy for PEDV infection.

Insights and progress on epidemic characteristics, genotyping, and preventive measures of PEDV in China: A review

Porcine Epidemic Diarrhoea (PED) is an acute, extremely infectious intestinal disease of pigs caused by the Porcine Epidemic Diarrhoea Virus (PEDV). The virus can affect pigs of all breeds and age groups and shows varying degrees of symptoms, with piglets, in particular, being infected with mortality rates of up to 100%. PEDV was first identified in China in the 1980s and in October 2010 a large-scale PED outbreak caused by a variant of PEDV occurred in China, resulting in huge economic losses. Initially, vaccination can effectively prevent the classical strain, but since December 2010, the PEDV variant has caused "persistent diarrhoea" with severe vomiting, watery diarrhoea, and high morbidity and mortality in newborn piglets as the dominant clinical features, with a significant increase in morbidity and mortality. This indicates that PEDV strains have mutated during evolution and that traditional vaccines no longer provide effective cross-immune protection, so it is necessary to optimize immunization programs and find effective treatments through epidemiological surveys of PEDV to reduce the economic losses caused by infections with mutated strains. This article reviews the progress of research on the aetiology, epidemiological characteristics, genotyping, pathogenesis, transmission routes, and comprehensive control of PEDV infection in China.

Development of a Genetically Engineered Bivalent Vaccine against Porcine Epidemic Diarrhea Virus and Porcine Rotavirus

Porcine epidemic diarrhea virus (PEDV) is an enteric coronavirus that causes acute diarrhea, vomiting, dehydration, and a high mortality rate in neonatal piglets. In recent years, PEDV has been associated with co-infections with other swine enteric viruses, including porcine rotavirus (PoRV), resulting in increased mortality among newborn piglets. In this paper, we developed a bivalent vaccine against PEDV and PoRV by constructing a recombinant PEDV encoding PoRV VP7 (rPEDV-PoRV-VP7). The recombinant virus was constructed by replacing the entire open reading frame 3 (ORF3) in the genome of an attenuated PEDV strain YN150 with the PoRV VP7 gene using reverse genetic systems. Similar plaque morphology and replication kinetics were observed in Vero cells with the recombinant PEDV compared to the wild-type PEDV. It is noteworthy that the VP7 protein could be expressed stably in rPEDV-PoRV-VP7-infected cells. To evaluate the immunogenicity and safety of rPEDV-PoRV-VP7, 10-day-old piglets were vaccinated with the recombinant virus. After inoculation, no piglet displayed clinical symptoms such as vomiting, diarrhea, or anorexia. The PoRV VP7- and PEDV spike-specific IgG in serum and IgA in saliva were detected in piglets after rPEDV-PoRV-VP7 vaccination. Moreover, both PoRV and PEDV neutralizing antibodies were produced simultaneously in the inoculated piglets. Collectively, we engineered a recombinant PEDV expressing PoRV VP7 that could be used as an effective bivalent vaccine against PEDV and PoRV.

Porcine epidemic diarrhea virus: Molecular mechanisms of attenuation and vaccines

Porcine epidemic diarrhea virus (PEDV) causes an emerging and re-emerging coronavirus disease characterized by vomiting, acute diarrhea, dehydration, and up to 100% mortality in neonatal suckling piglets, leading to huge economic losses in the global swine industry. Vaccination remains the most promising and effective way to prevent and control PEDV. However, effective vaccines for PEDV are still under development. Understanding the genomic structure and function of PEDV and the influence of the viral components on innate immunity is essential for developing effective vaccines. In the current review, we systematically describe the recent developments in vaccine against PEDV and the roles of structural proteins, non-structural proteins and accessory proteins of PEDV in affecting viral virulence and regulating innate immunity, which will provide insight into the rational design of effective and safe vaccines for PEDV or other coronaviruses.

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Advances in vaccines of PEDV, such as inactivated and attenuated live vaccines, subunit vaccines, and nucleic acid vaccines.

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The application of reverse genetics in the development of live attenuated PEDV vaccines.

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The roles of PEDV proteins in affecting viral virulence and regulating innate immunity.

Evaluation of the Efficacy of a Recombinant Adenovirus Expressing the Spike Protein of Porcine Epidemic Diarrhea Virus in Pigs

In recent years, many studies have shown that recombinant adenovirus live vector-based vaccines are a promising novel vaccine candidate against virus infection. Therefore, in this study, a new type of recombinant adenovirus expressing the spike (S) protein of porcine epidemic diarrhea virus (PEDV), rAd-PEDV-S, was generated, and its characteristics were determined. Then, its efficacy as a vaccine candidate was evaluated in 4-week-old pigs. The results showed that the S protein could be well expressed at a high level in rAd-PEDV-S-infected cells and that the viral titers could reach 10¹¹ PFU/mL. Further animal experimental results showed that rAd-PEDV-S elicited a significant PEDV-specific humoral immune response after vaccination (P < 0.05). In addition, rAd-PEDV-S provided partial protection for pigs against the highly virulent PEDV challenge. The results presented in this study indicate that the adenovirus vector can be used as a vaccine delivery vector for the development of a PEDV vaccine and is a promising novel vaccine candidate for future prevention and control of porcine epidemic diarrhea (PED), but its efficacy still needs to be improved in the future.