Introduction: Staphylococcus aureus seriously threatens human and animal health. IsdB_137‐361 of the iron surface determinant B protein (IsdB) from S. aureus exhibits the strong immunogenicity, but its immunoprotective effect is still to be further promoted. Because PEI‐PLGA nanoparticles are generated by PEI conjugate with PLGA to develop great potential as a novel immune adjuvant, the immunogenicity of IsdB_137‐361 is likely be strengthened by PEI‐PLGA.Methods: Here, PEI‐PLGA nanoparticles containing IsdB_137‐361 proteins were prepared by optimizing the entrapment efficiency. Mice were immunized with IsdB_137‐361‐PEI‐PLGA nanoparticles to assess their anti‐S. aureus effects. The level of IFN‐γ, IL‐4, IL‐17, and IL‐10 cytokines from spleen lymphocytes in mice and generation of the antibodies against IsdB_137‐361 in serum was assessed by ELISA, the protective immune response was appraised by S. aureus challenge.Results: IsdB_137‐361 proteins loaded by PEI‐PLGA were able to stimulate effectively the proliferation of spleen lymphocytes and increase the secretion of IFN‐γ, IL‐4, IL‐17, and IL‐10 cytokine from spleen lymphocytes, and significantly enhance generation of the antibodies against IsdB_137‐361 in serum, reduce the level of bacterial load in liver, spleen and kidney, and greatly improve the survival rate of mice after challenge.Conclusion: These data showed that PEI‐PLGA nanoparticles can significantly enhance the immunogenicity of IsdB_137‐361 proteins, and provide an important reference for the development of novel immune adjuvant.

Porcine epidemic diarrhea virus (PEDV) infection induces severe, often fatal, watery diarrhea and vomiting in neonatal piglets, characterized by profound dehydration, villus atrophy, and catastrophic mortality rates approaching 100% in unprotected herds. This study developed a composite probiotic from Min-pig-derived Lactobacillus crispatus LCM233, Ligilactobacillus salivarius LSM231, and Lactiplantibacillus plantarum LPM239, which exhibited synergistic growth, potent acid/bile salt tolerance, and broad-spectrum antimicrobial activity against pathogens. In vitro, the probiotic combination disrupted pathogen ultrastructure and inhibited PEDV replication in IPI-2I cells. In vivo, PEDV-infected piglets administered with the multi-strain probiotic exhibited decreased viral loads in anal and nasal swabs, as well as in intestinal tissues. This intervention was associated with the alleviation of diarrhea symptoms and improved weight gain. Furthermore, the multi-strain probiotic facilitated the repair of intestinal villi and tight junctions, increased the number of goblet cells, downregulated pro-inflammatory cytokines, enhanced the expression of barrier proteins, and upregulated antiviral interferon-stimulated genes. These findings demonstrate that the multi-strain probiotic mitigates PEDV-induced damage by restoring intestinal barrier homeostasis and modulating immune responses, providing a novel strategy for controlling PEDV infections.

Introduction. The development of combinatorial adjuvants is a promising strategy to boost vaccination efficiency. Accumulating evidence indicates that manganese exerts strong immunocompetence and will become an enormous potential adjuvant. Here, we described a novel combination of Mn²⁺ plus aluminum hydroxide (AH) adjuvant that significantly exhibited the synergistic immune effect. Methodology. Initially, IsdB3 proteins as the immune-dominant fragment of IsdB proteins derived from Staphylococcus aureus (S. aureus) were prepared. IsdB3 proteins were identified by western blotting. Furthermore, we immunized C57/B6 mice with IsdB3 proteins plus Mn²⁺ and AH adjuvant. After the second immunization, the proliferation of lymphocytes was measured by the cell counting kit-8 (CCK-8) and the level of IFN-γ, IL-4, IL-10, and IL-17 cytokine from spleen lymphocytes in mice and generation of the antibodies against IsdB3 in serum was detected with ELISA, and the protective immune response was assessed through S. aureus challenge. Results. IsdB3 proteins plus Mn²⁺ and AH obviously stimulated the proliferation of spleen lymphocytes and increased the secretion of IFN-γ, IL-4, IL-10, and IL-17 cytokine in mice, markedly enhanced the generation of the antibodies against IsdB3 in serum, observably decreased bacterial load in organs, and greatly improved the survival rate of mice. Conclusion. These data showed that the combination of Mn²⁺ and AH significantly acted a synergistic effect, reinforced the immunogenicity of IsdB3, and offered a new strategy to increase vaccine efficiency.

Infection of cattle with bovine herpesvirus type 1 (BHV−1) can lead to upper respiratory tract disease, conjunctivitis, or genital disease and cause serious economic losses to the cattle industry worldwide. The role of long noncoding RNAs in BHV−1 infection is not well understood. To explore the role of lncRNA−MSTRG.16919.1 in bovine herpes virus type I (BHV−1) infected MDBK cells, the lncRNA−MSTRG.16919.1 gene was silenced and sequenced transcriptome and sequencing data were analyzed by Edge R software, Gene Ontology (GO), the Kyoto Encyclopedia of Genes and Genomes (KEGG), and an interaction network of proteins. Real−time quantitative PCR (RT−qPCR) and Western blotting were used to verify the results of bioinformatic analyses. The results showed that 1151 differential genes were obtained in the siRNA−MSTRG.16919.1 group compared with an NC group. Compared with BHV−33 h, 6586 differentially expressed genes were obtained. A total of 498 differentially expressed genes were screened from the two groups. To verify the accuracy of the sequencing, six genes were randomly selected for RT−qPCR, and the results showed that the expression trend of selected genes was consistent with the sequencing results. GO enrichment analysis showed that the differential genes were related to such biological processes as nucleotide binding, enzyme binding, cell cycle, and glial macromolecule metabolism. KEGG analysis enriched 378 and 2634 signaling pathways, respectively, that were associated with virus infection, ubiquitin−mediated protein hydrolysis, phosphoinositol metabolism, apoptosis, and other metabolic pathways. The STRING protein interaction database was used to analyze the interaction network of proteins encoded by differential genes, and the degree algorithm in Cytoscape was used to screen the top 20 proteins. The results showed that SKIV2L2, JAK2, PIK3CB, and MAPK8 were related to virus infection. Western blot analysis of TNF, NF−κB, MAPK8, MAPK9, and MAPK10 proteins showed that lncRNA−MSTRG.16919.1 was involved in regulating the expression of these functional proteins. The results of this study provide basic information for exploring the function and regulatory mechanism of lncRNA−MSTRG.16919.1 in organisms and help for further studying the interaction between virus and host.

Staphylococcus aureus is a leading cause of severe infections in humans and animals, and the emergence of multidrug-resistant strains highlights the need to develop effective vaccines to prevent such diseases. Epitope-based vaccines use short antigen-derived peptides corresponding to immune epitopes, which are administered to trigger protective humoral and cellular immune responses. In this study, in silico MHC affinity measurement methods were used to predict possible binding regions, and five 20-mer synthetic TRAP peptides (TRAPP) were synthesized. Epitope-based vaccines, named PT and PTR, incorporating the identified CD4⁺ T and B cell epitopes, were constructed. Peptides TRAP_20–39 and TRAP_94–113 elicited significant peptide-stimulated T-cell proliferation responses in vivo. Additionally, high levels of IFN-γ and IL-17A, along with moderate levels of IL-4, were detected in ex vivo stimulated CD4⁺ T cells isolated from rTRAP- and TRAPP-immunized mice, suggesting that these peptides are classified as Th1 and Th17 epitopes. Immunization with PT or PTR induces robust humoral and cellular immune responses. Moreover, the epitope-based vaccine, PT, exhibited a stronger protective immune response than the intact TRAP in a murine systemic S. aureus infection model. Based on the results presented herein, an epitope-based vaccine is a promising and potentially more effective candidate.