The continuously evolving PRRSV has been plaguing pig farms worldwide for over 30 years, with conventional vaccines suffering from insufficient protection and biosecurity risks. To address these challenges, we identified 10 PRRSV-specific CTL epitopes through enzyme-linked immunospot assay (ELISPOT) and constructed a multi-epitope peptide (PTE) by linking them in tandem. This PTE was then fused with a modified porcine Fc molecule to create the recombinant protein pFc-PTE. Our findings indicate that pFc-PTE effectively stimulates PRRSV-infected specific splenic lymphocytes to secrete high levels of interferon-gamma (IFN-γ) and is predicted to be non-toxic and non-allergenic. Compared to PTE alone, pFc-PTE not only induced a comparable cellular immune response in mice but also extended the duration of the immune response to at least 10 weeks post-immunization. Additionally, pFc-PTE predominantly induced a Th1 immune response, suggesting its potential advantage in enhancing cellular immunity. Consequently, pFc-PTE holds promise as a novel, safe, and potent candidate vaccine for PRRSV and may also provide new perspectives for vaccine design against other viral diseases.

Porcine epidemic diarrhea virus (PEDV) is a highly contagious coronavirus that infect pigs’ intestinal epithelial cells, causing high morbidity and mortality. Due to the rapid mutation of PEDV, vaccine efficacy is uncertain, prompting exploration of alternative treatments. Nanobodies, also known as variable heavy chain domains of heavy chain-only antibodies (VHHs), offer significant potential in biomedical applications due to their small size and high specificity. In this study, yeast two-hybrid technology was employed to screen for eight specific VHH sequences targeting the PEDV S protein from a synthetically constructed nanobody yeast library. The VHH genes were then cloned into expression plasmids for recombinant protein production, and the resulting VHHs (termed PEDV S-VHHs) were purified. Indirect immunofluorescence assay (IFA) and Western blotting analysis confirmed that these VHHs specifically bind to both PEDV and its S protein. Neutralization assays demonstrated that seven PEDV S-VHHs exhibited potent neutralizing activity against PEDV. Additionally, a combination of these seven antibodies showed enhanced antiviral effects. Preliminary predictions were also made regarding the binding sites between these VHHs and PEDV. The PEDV S-VHHs described in this study hold potential as candidates for the prevention and treatment of PEDV infection.

Pseudorabies virus (PRV) is a highly contagious pathogen in swine that can cross species barriers and infect other mammals, including humans. Given the potential for interspecies transmission and its threat to public health, understanding the molecular biology of PRV strains is essential for developing effective control measures and preparing for future pandemics. In this study, a novel PRV strain, PRV-HL-2021, was isolated from an outbreak in Heilongjiang Province, China. The viral genome was used to establish a reverse genetics system based on a fosmid library of the PRV-HL-2021 genome. This system facilitated the creation of recombinant PRV, including one expressing EGFP and another with deletions in the US9, gI, and gE genes. PRV-HL-2021 was found to be highly lethal to mice in vivo. The recombinant PRV strains, such as rPRV-US9-EGFP and rPRV-delgI/gE/US9, exhibited growth characteristics similar to the parental PRV-HL-2021 strain. The isolation and characterization of PRV-HL-2021 contribute to a better understanding of the genetic diversity of PRV strains. The developed reverse genetics system provides valuable tools for investigating viral functions, creating genetically modified PRV strains, and advancing the development of safer vaccines. These findings will enhance strategies for controlling PRV outbreaks and mitigating its impact on both animal and public health.

Sujiang pigs, a high-quality local Chinese breed, represent a valuable model for investigating muscle development and improving meat production through genetic selection. Skeletal muscle satellite cells (MuSCs) are essential regulators of muscle growth, with differentiation tightly controlled by specific genes and signaling pathways. In this study, MuSCs were isolated from the gastrocnemius muscle and subjected to mRNA sequencing during proliferation (GM) and differentiation stages (DM1, DM2, and DM4, collectively referred to as DM). A total of 2790 differentially expressed genes (DEGs) were identified, including 1551 upregulated and 1239 downregulated genes. Time-series analysis revealed 16 significant expression patterns. These DEGs were primarily associated with muscle development and differentiation and were enriched in Wnt, PI3K–Akt, JAK–STAT, p53, Hippo, and Apelin signaling pathways. Among them, phosphoribosyl transferase domain containing 1 (PRTFDC1) exhibited pronounced downregulation during differentiation. Functional validation demonstrated that PRTFDC1 overexpression promoted myotube formation and upregulated MYOD1, MYOG, and MYH1 expression, whereas knockdown significantly inhibited differentiation. Furthermore, PRTFDC1 enhanced phosphorylation of key proteins in the cGAS–STING signaling pathway. Collectively, this study elucidates the temporal transcriptional regulation of MuSC differentiation in Sujiang pigs and identifies PRTFDC1 as a novel regulatory factor, providing a molecular foundation for breeding strategies and meat quality improvement.

Porcine deltacoronavirus (PDCoV) poses a significant threat to the global swine industry, underscoring the urgent need for effective vaccines. In this study, a self-assembling ferritin-based nanoparticle vaccine displaying the PDCoV spike receptor-binding domain (S-RBD), designated PDCoV-S-RBD-FR, was constructed and evaluated for its immunogenicity and safety. Transmission electron microscopy (TEM) showed that the recombinant PDCoV-S-RBD-FR protein formed spherical nanoparticles with a mean diameter of 25.55 ± 4.39 nm. In mice, immunization with PDCoV-S-RBD-FR elicited antigen-specific IgG responses, with titers reaching 1:40,960 following booster immunization. Significantly elevated serum IFN-γ and IL-4 levels were observed following immunization. Notably, virus neutralization assays demonstrated that the vaccine induced functional neutralizing antibodies (titer 1:128) capable of effectively blocking PDCoV-induced cytopathic effects in vitro. Histopathological examination of the heart, liver, spleen, lungs, and kidneys revealed no significant lesions in immunized mice relative to the PBS control group, suggesting good tolerability in mice. Collectively, these findings indicate that the ferritin-based PDCoV-S-RBD nanoparticle vaccine elicits antigen-specific IgG responses together with elevated serum cytokine levels and functional neutralizing activity in vitro and no detectable histopathological alterations in major organs, supporting its further evaluation as a vaccine candidate against PDCoV.

Skeletal muscle satellite cells (MuSCs) are essential for muscle growth and development, but their regulatory mechanisms remain unclear. This study aimed to characterize the expression pattern of pleomorphic adenoma gene 1 (PLAG1), determine its effects on MuSC proliferation and differentiation, and explore its potential regulatory mechanisms through integrated transcriptomic and ceRNA analyses in Sujiang pig MuSCs. Results showed that PLAG1 was widely expressed in multiple porcine tissues and was significantly upregulated during MuSC differentiation. PLAG1 overexpression promoted MuSC proliferation and differentiation, whereas PLAG1 knockdown produced the opposite effects. Whole-transcriptome sequencing following PLAG1 knockdown identified 432 differentially expressed mRNAs, 70 miRNAs, 163 lncRNAs, and 150 circRNAs. Enrichment analysis revealed that differentially expressed mRNAs were mainly associated with cell cycle regulation, DNA replication, and the p53 signaling pathway. Western blot analysis further showed that PLAG1 knockdown reduced CDK1 and PCNA protein levels. ceRNA network analysis revealed potential regulatory associations among differentially expressed lncRNAs, circRNAs, miRNAs, and mRNAs, and the expression changes in selected differentially expressed RNAs were further validated by qRT-PCR. Collectively, these findings indicate that PLAG1 promotes MuSC proliferation and differentiation and may be associated with cell cycle-related gene expression changes and potential non-coding RNA regulatory networks in porcine MuSCs.