Search Results (223)

Clostridium perfringens is one of the main causes of death in poultry with no vaccines approved for poultry at present. The appropriate adjuvant is critical for the development of vaccines in C. perfringens in poultry. Here, we utilized Levilactobacillus brevis for high-yielding selenium biotransformation and demonstrated that heat-inactivated nano-selenium Lactobacillus (HiSeL) is a safe, efficient, and chemically stable selenium immunopotentiator for C. perfringens vaccines. We evaluated the effectiveness of HiSeL as an immune adjuvant to modulate the efficacy of multi-epitope vaccine in mice. Subcutaneous immunization mice with HiSeL promoted high levels of specific IgG, modulated cytokine secretion, downregulated stress-related gene expression, and provided 100% protection against lethal challenge with C. perfringens. Surprisingly, we found that HiSeL can quickly and effectively induce SIgA production even by subcutaneous immunization. Transcriptome sequencing revealed the pivotal role of TGF-β and NF-κB signaling pathways in IgA immune responses in mice immunized with the HiSeL-adjuvanted multi-epitope vaccine. Collectively, our study provides proof-of-concept evidence that HiSeL functions as a potent adjuvant candidate for the multi-epitope vaccine in a murine model, offering new insights into the development of engineered postbiotic-based adjuvants. Full article

Background: Norovirus GII.4 is a major global health threat, yet no licensed vaccines exist due to the virus’s rapid evolution and high mutation rates. Objective: To rationally design and experimentally validate multi-epitope vaccine candidates against Norovirus GII.4 using computational immunoinformatics and in vivo evaluation. Methods: We employed reverse vaccinology to screen optimal norovirus GII.4 epitopes and systematically designed four construction strategies to evaluate different epitope topologies and adjuvants. Candidates underwent molecular dynamics simulations and were expressed in E. coli. Immunogenicity was assessed in BALB/c mice via ELISA and ELISPOT to evaluate humoral and cellular responses. Results: Three candidates (NV1, NV4, NV5) were successfully produced and induced cross-reactive antibodies against authentic GII.4 virus-like particles. Notably, the construction strategy influenced the immune response: NV5 (repetitive epitopes and HSP as adjuvant) elicited the highest antigen-specific antibody titers, NV1 (all types of epitopes and TLR as adjuvant) induced the strongest cellular response, and NV4 (repetitive epitopes and TLR as adjuvant) achieved the most rapid immune response. Consistently, in silico analysis showed that the NV1-TLR3 complex exhibits tighter interaction, higher binding energy, and greater structural stability, supporting its superior capacity to trigger cellular immunity. Conclusions: A rational multi-epitope vaccine design workflow successfully realized the translation from computational design to functional vaccines. Optimizing adjuvant selection and epitope construction is critical for eliciting immune responses in next-generation norovirus vaccines. Full article

Background/Objectives: The Zika virus (ZIKV) represents an ongoing threat to public health due to its neurological and congenital complications. Even after 10 years since the first major outbreak, correlated with an increase in congenital ZIKV syndrome, there is still no vaccine or treatment for this infection. Among the various existing platforms, DNA vaccines combined with the use of immunoinformatics tools allow for the efficient selection of immunogenic epitopes and immunostimulatory molecules with greater flexibility, in addition to being simple to manufacture and having a higher cost–benefit ratio in production. Methods: In this work, we conducted an integrated approach, combining in silico analyses and in vivo experimental validations, for the development of multi-epitope DNA vaccines against ZIKV. The computational analyses confirmed structural stability, adequate solubility, absence of toxicity, and immune induction potential for constructs based on epitopes from the Envelope (E) and NS1 proteins. Therefore, we evaluated DNA constructs containing the ENV + NS1 epitopes, both with and without fusion to the ssPGIP signal peptide, in BALB/c mice. Results: Both vaccines increased the population of CD4⁺ and CD8⁺ T lymphocytes, in addition to the production of IgG antibodies associated with the Th1 profile. The fusion with ssPGIP broadened the response, stimulating the release of Th1, Th2, and Th17 cytokines, as well as enhancing antibody formation. In contrast, its absence was associated with a slight increase in CD4⁺ and CD8⁺ T cells, accompanied by restricted cytokine production. Conclusions: These results indicate that epitope-targeted techniques offer a viable and safe method for inducing robust immune responses, demonstrating that combining immunoinformatics methods with early preclinical testing is an effective strategy for ZIKV vaccine development. Furthermore, although the present study focused on initial immunogenic characterization, future studies involving viral challenge in a suitable animal model will be essential to conclusively determine the protective efficacy of these vaccine candidates. Full article

The global incidence of multidrug-resistant (MDR) ESKAPE pathogens—comprising Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species—has surged alarmingly in recent years, posing a significant challenge to healthcare systems worldwide. These organisms are notorious for their capacity to evade the effects of multiple classes of antibiotics, leading to treatment failures, increased morbidity and mortality, and escalating healthcare costs, all of which have placed unprecedented strain on existing infection control measures. This review encapsulates the progress in target-driven vaccine research, including the genomic discovery of highly conserved surface antigens, iron acquisition systems, biofilm- and quorum-sensing-related proteins, and computationally predicted epitopes, which are considered the most attractive targets for broad-spectrum vaccination. Novel vaccine platforms, such as outer membrane vesicles (OMVs), mRNA technologies, and multi-epitope constructs, will rapidly drive the translation of these targets into next-generation vaccine formulations. Nevertheless, challenges such as antigenic variation and immune evasion, as well as the need for a robust mucosal and cross-protective immune response, persist. The sustainability in interdisciplinary investigations are required, along with adjunctive measures and investment in the development of advanced discovery and delivery systems, to achieve the ultimate goal of successful vaccines against MDR ESKAPE infections and to mitigate the worldwide burden of antimicrobial resistance. Full article

Background: Chromobacterium violaceum is an emerging multidrug-resistant (MDR) Gram-negative bacterium associated with severe septicemia, abscess formation, and high mortality, particularly in immunocompromised individuals. Increasing antimicrobial resistance and the absence of approved vaccines underscore the urgent need for alternative preventive strategies. Traditional vaccine approaches are often inadequate against genetically diverse MDR pathogens, prompting the use of computational immunology and reverse vaccinology for vaccine design. Objectives: This study aimed to design and characterize a novel multi-epitope subunit vaccine (MEV) candidate against C. violaceum using a comprehensive pangenome-guided subtractive proteomics and immunoinformatics pipeline to identify conserved antigenic targets capable of eliciting strong immune responses. Methods: Comparative genomic analysis across eight C. violaceum strains identified 3144 core genes. Subtractive proteomics filtering yielded two essential, non-homologous, surface-accessible, and antigenic proteins—penicillin-binding protein 1A (Pbp1A) and organic solvent tolerance protein (LptD)—as vaccine targets. Cytotoxic T-lymphocyte (CTL), helper T-lymphocyte (HTL), and B-cell epitopes were predicted and integrated into a 272-amino-acid MEV construct adjuvanted with human β-defensin-4A using optimal linkers. The construct was evaluated through structural modeling, molecular docking with TLR4, molecular dynamics simulation, immune simulation, and in silico cloning into the pET-28a(+) vector. Results: The MEV construct exhibited strong antigenicity, non-allergenicity, and non-toxicity, with stable tertiary structure and favorable physicochemical properties. Docking and dynamics simulations demonstrated high binding affinity and stability with TLR4 (ΔG = −16.2 kcal/mol), while immune simulations predicted durable humoral and cellular immune responses with broad population coverage (≈89%). Codon optimization confirmed high expression potential in E. coli K12. Conclusions: The pangenome-guided immunoinformatics approach enabled the identification of conserved antigenic proteins and rational design of a promising multi-epitope vaccine candidate against MDR C. violaceum. The construct exhibits favorable immunogenic and structural features, supporting its potential for experimental validation and future development as a preventive immunotherapeutic against emerging MDR pathogens. Full article

Background: Tuberculosis (TB) remains a pressing global health crisis. The inadequate efficacy of the BCG vaccine against adult pulmonary TB underscores the urgent need for novel, effective vaccines. This study aimed to design a novel mRNA vaccine candidate against TB using a rational immunoinformatics approach. Methods: From 13 antigens, >12,000 epitopes were filtered to select 60 optimal peptides (36 CTL, 16 HTL, 8 B-cell), assembled into 25 scaffolds with 49 TLR2/4 agonist configurations. EP9158H underwent structural modeling, 100 ns molecular dynamics, docking, immune simulation, RNAfold, and conservation analysis across 76 strains. Results: EP9158H, encoding 15 CTL, 9 HTL, and 8 B-cell epitopes flanked by TLR2 agonist ESAT-6 and TLR4 agonist HBHA, emerged as the optimal candidate. All 32 constituent epitopes showed >81% conservation, with 81.25% exhibiting perfect identity across MTBC lineages. The scaffold demonstrated high solubility (0.531), broad population coverage (73.76% MHC-I, 88.91% MHC-II), optimal TLR2/4 docking scores (−1359.7 and −1348.3), and robust structural stability (ProSA Z-score −6.18; RMSD 22–27 Å). Immune simulation predicted strong Th1-biased T-cell responses and high levels of antibody titers. RNAfold analysis revealed stable mRNA secondary structures (MFE −1127.5 kcal/mol) supporting efficient translation. Conclusions: EP9158H integrates broad epitope coverage, dual TLR agonism, and validated stability. Compared to single-antigen vaccines, it offers superior strain coverage, enhanced innate activation, and mRNA advantages for CTL induction, warranting experimental validation. Full article

No vaccines are licensed against enterotoxigenic Escherichia coli (ETEC), a leading diarrheal cause in children and travelers. ETEC adhesins and enterotoxins are the virulence determinants and become the primary targets in ETEC vaccine development. However, ETEC strains produce > 25 adhesins and two potent enterotoxins, particularly the poorly immunogenic heat-stable toxin (STa), greatly hindering ETEC vaccine development. To overcome these challenges, we developed a multiepitope-fusion-antigen (MEFA) platform. MEFA presented multiple adhesin epitopes on a backbone and generated a polyvalent adhesin immunogen, CFA/I/II/IV MEF. CFA/I/II/IV protected against the seven ETEC adhesins (CFA/I, CS1-CS6) associated with two-thirds of ETEC diarrheal cases. We further used toxoids as safe antigens and created a toxoid fusion, 3xSTa_N12S-mnLT_R192G/L211A. This antigen induced antibodies neutralizing the enterotoxicity of STa and heat-labile toxin (LT), which, alone or together, cause all ETEC diarrheal cases. By combining two polyvalent proteins, we developed a multivalent ETEC vaccine, MecVax, that protects against seven ETEC adhesins and two enterotoxins. MecVax is broadly immunogenic. MecVax prevents intestinal colonization by ETEC strains expressing any of the seven adhesins and protects against clinical diarrhea from ETEC strains producing LT or STa enterotoxin preclinically, becoming a broadly protective ETEC vaccine candidate against children’s diarrhea and travelers’ diarrhea. Full article

The landscape of cancer immunotherapy has been redefined by mRNA vaccines as rapid clinically viable strategies that help induce potent, tumor-specific immune responses. This review highlights the current advances in mRNA engineering and antigen design to establish an integrated immunological framework for cancer vaccine development. Achieving durable clinical benefit requires more than antigen expression. Effective vaccines need precise epitope selection, optimized delivery systems, and rigorous immune monitoring. The field is shifting from merely inducing immune responses to focusing more on the biochemistry and molecular design principles that combine magnitude, polyfunctionality, and longevity to overcome tumor-induced immune suppression. We examine an integrated immunological framework for mRNA cancer vaccine development, examining how rational molecular engineering of vaccine components, from nucleoside modifications and codon optimization to untranslated regions and linker sequences, shapes immunogenicity and therapeutic efficacy. Future directions will depend on balancing combinatorial strategies combining vaccination with immune checkpoint inhibitors and adoptive cell therapies. Full article

The diseases caused by genotype VII Newcastle disease virus (NDV), H9N2 avian influenza virus (AIV), and fowl adenovirus serotype 4 (FAdV-4) continue to threaten the global poultry industry. However, no broad-spectrum vaccines provide simultaneous protection against these three pathogens. This study employed bioinformatics and immunoinformatics approaches to design a multi-epitope vaccine, named NFAF, which consists of B-cell, cytotoxic T lymphocyte (CTL) epitopes, and helper T lymphocyte (HTL) epitopes derived from hemagglutinin-neuraminidase (HN) and fusion (F) proteins of genotype VII NDV, hemagglutinin (HA) protein of H9N2, and Fiber2 protein of FAdV-4. The vaccine candidate was predicted to have non-allergenic properties, non-toxicity, high antigenicity, and favorable solubility. Each of its constituent antigenic epitopes has a high degree of conservation. Molecular docking demonstrated stable binding between NFAF and chicken Toll-like receptor (TLRs) and major histocompatibility complex (MHC) molecules. NFAF was expressed in soluble form in Escherichia coli and purified. Polyclonal antibodies against all three target viruses showed specific binding to NFAF. In vitro experiments revealed that NFAF effectively stimulated chicken peripheral blood mononuclear cells (PBMCs) and induced Th1, Th2, and pro-inflammatory cytokine production, confirming its immunogenicity, and increased the mRNA expression of the key signaling molecules MyD88 and NF-κB. These results suggested that NFAF could therefore be an efficacious multi-epitope vaccine against genotype VII NDV, H9N2, and FAdV-4 infections. Full article

Duck viral hepatitis (DVH), a highly contagious disease, is caused primarily by duck hepatitis A virus (DHAV). The viral genotypes exhibit significant diversity, creating a challenge as monovalent vaccines fail to provide cross-genotype protection in ducklings. This study aimed to design a multi-epitope peptide vaccine targeting different genotypes of DHAV. Using immunoinformatics approaches, we systematically identified key antigenic determinants, including linear B-cell epitopes, cytotoxic T-cell epitopes (CTL), and helper T-cell epitopes (HTL). Based on these, a novel vaccine candidate was developed. The vaccine construct was subjected to rigorous computational validation: (1) Molecular docking with Toll-like receptors (TLRs) predicted immune interaction potential. (2) Molecular dynamics simulations assessed complex stability. (3) In silico cloning ensured prokaryotic expression feasibility. Then, we conducted preliminary experimental validation for the actual effect of the vaccine candidate, including recombinant protein expression in E. coli, enzyme-linked immunosorbent assay (ELISA) quantification of humoral responses, and Western blot analysis of cross-reactivity. ELISA results demonstrated that the vaccine candidate could induce high-titer antibodies in immunized animals, with potency reaching up to 1:128,000, and the immune serum showed strong reactivity with recombinant VP proteins. Western blot analysis using duck sera confirmed epitope conservancy across genotypes. Collectively, the multi-epitope vaccine candidate developed in this study represents a highly promising broad-spectrum strategy against DHAV. The robust humoral immunity it elicits, coupled with its demonstrated cross-reactivity, constitutes compelling proof-of-concept, laying a solid foundation for advancing to subsequent challenge trials and translational applications. Full article

Background/Objectives: Varicellovirus bovinealpha1 and Varicellovirus bovinealpha5 (BoAHV-1 and BoAHV-5), respectively, are widely distributed pathogens that cause distinct clinical conditions in cattle including infectious bovine rhinotracheitis, infectious pustular vulvovaginitis/balanoposthitis, and meningoencephalitis. Due to the establishment of viral latency, controlling these infections is challenging, and vaccination remains the most effective strategy. In this study, vaccine candidates targeting both BoAHV-1 and BoAHV-5 were developed. Methods: A synthetic gene encoding immunodominant epitopes from the gB and gD proteins and tegument phosphoprotein of BoAHV-1 and BoAHV-5 was designed to produce a multi-epitope recombinant antigen, expressed both in a prokaryotic system (RecBoAHV) and by a modified vaccinia Ankara (MVA-BoAHV) viral vector. The binding affinity of MHC-I to bovine leukocyte antigens (BoLA) was predicted using the NetMHCpan tool (version 4.1). The immunogenicity of the vaccine candidates was evaluated in rabbit and mouse models, using prime-boost immunization protocols. Sera from bovines naturally infected with BoAHV-1 and/or BoAHV-5 were used to evaluate the chimeric protein antigenicity. Immune responses were assessed by indirect ELISA and Western blot. Results: The recombinant multi-epitope protein was effectively recognized by IgG and IgM antibodies in sera from cattle naturally infected with BoAHV-1 or BoAHV-5, confirming the antigenic specificity. Both RecBoAHV and MVA-RecBoAHV induced strong and specific humoral immune responses in rabbits following a homologous prime-boost regimen. In mice, both homologous and heterologous prime-boost protocols revealed robust immunogenicity, particularly after the second booster dose. Conclusions: These findings highlight the immunogenic potential of the RecBoAHV multi-epitope vaccine candidates for controlling BoAHV-1 and BoAHV-5 infections. Further characterization of these vaccine formulations is currently underway in bovine, the target specie. Full article

Background: Mammalian orthoreovirus is a ubiquitous double-stranded RNA virus that causes mild respiratory and enteric infections, primarily in infants and young children. Its significant environmental stability and association with conditions like celiac disease highlight an unmet medical need, as no licensed vaccine or antiviral treatment currently exist. Methods: An immunoinformatics-driven approach was employed to design a multi-epitope vaccine. The highly antigenic inner capsid protein Sigma-2 was used to predict cytotoxic T lymphocyte (CTL), helper T lymphocyte (HTL), and linear B cell epitopes using NetCTL, NetMHCpan, NetMHCIIpan, and IEDB tools. Selected epitopes were fused with appropriate linkers. The construct’s antigenicity, allergenicity, and physicochemical properties were evaluated. The tertiary structure was predicted with AlphaFold2, refined, and validated. Molecular docking with TLR2 and TLR4 was performed using HDOCK, and immune response simulation was conducted with C-ImmSim. Finally, the sequence was codon-optimized for E. coli expression using JCat. Results: The final vaccine construct comprises one CTL, four HTLs, and one B cell epitope. It is antigenic (VaxiJen score: 0.5026), non-allergenic, and non-toxic and possesses favorable physicochemical properties, including stability (instability index: 32.28). Molecular docking revealed exceptionally strong binding to key immune receptors, particularly TLR2 (docking score: −324.37 kcal/mol). Immune simulations predicted robust antibody production (elevated IgM, IgG1, and IgG2) and lasting memory cell formation. Codon optimization yielded an ideal CAI value of 0.952 and a GC content of 57.15%, confirming high potential for recombinant expression. Conclusions: This study presents a novel multi-epitope vaccine candidate against reovirus, designed to elicit broad cellular and humoral immunity. Comprehensive in silico analyses confirm its structural stability, potent interaction with innate immune receptors, and high potential for expression. These findings provide a strong rationale for further wet-lab studies to validate its efficacy and advance it as a promising prophylactic candidate. Full article

Multi-epitopes of FMDV can be used to develop a novel vaccine. Determining how to screen naturally presenting epitope peptides derived from FMDV is crucial for advancing progress in this area. In this study, a transient expression plasmid named pEGFP-N1-VP1 was transfected into Porcine Kidney Epithelial cells 15 (PK15). The positive cells that stably expressed the O-VP1 gene of FMDV were screened with gradient concentrations of G418 (Geneticin). The constructed pEGFP-N1-VP1/PK15 cell line was eluted by pH 3.3 phosphate buffer to isolate the eluted peptides, followed by desalting, liquid chromatography–tandem mass spectrometry (LC–MS/MS), a flow cytometric analysis of SLA-I expression, and an ELISA detection of SLA-I bound peptides. It was demonstrated that a PK15 cell line stably expressing the VP1 gene was initially screened out at 500 μg/mL of G418, followed by culturing at 300 μg/mL. The O-VP1 expression was identified using an image analysis system, RT-PCR, and Western blot analysis. Thirty-seven peptides derived from O-VP1 were eluted from the constructed cell line. The flow cytometric analysis and ELISA detection results showed that the eluted peptides were associated with SLA-I and bound. This is the first known study to construct a cell line for screening naturally presenting antigenic peptides derived from the O serotype of FMDV. Full article

Background: Enterotoxigenic Escherichia coli (ETEC) is a zoonotic pathogen causing diarrhea and mortality in infants and livestock. Its numerous serotypes necessitate the urgent development of multivalent vaccines for effective prevention, thereby reducing public health and economic threats. Methods: Computational bioinformatics analyses were conducted on five major ETEC adhesins structural subunits (FaeG, FanC, FasA, FimF41a, and FedF). Dominant epitopes were selected and concatenated via flexible linkers, incorporating the PADRE sequence and LTb adjuvant to design a multi-epitope fusion antigen (MEFA). The recombinant MEFA protein was expressed in a prokaryotic system. Furthermore, molecular dynamics simulations, docking, and immune simulations assessed structural stability and immunogenicity. Immunoreactivity was tested by Western blot. Murine immunization evaluated antibody responses, lymphocyte proliferation, cytokine secretion, and protection against ETEC challenge. Results: Structural modeling showed an extended conformation, with docking and simulations indicating strong immune activation. Western blot confirmed MEFA immunoreactivity. MEFA induced high antigen-specific antibody titers, enhanced splenocyte proliferation, and increased IFN-γ and IL-4 secretion, indicating a Th2-biased response in mice. Vaccinated mice survived lethal ETEC challenge and maintained intestinal integrity. Conclusions: The MEFA candidate vaccine effectively induces robust humoral and cellular immune responses and provides protection against ETEC infection, representing a promising strategy for next-generation multivalent ETEC vaccines. Full article

The rapid emergence and evolution of avian viral pathogens present a major challenge to global poultry health and food security. Traditional vaccine development is often slow, costly, and limited by antigenic diversity. In this study, we present a comprehensive artificial intelligence (AI)-driven pipeline for the rational design, modeling, and optimization of multi-epitope vaccines targeting economically important RNA and DNA viruses affecting poultry, including H5N1, NDV, IBV, IBDV, CAV, and FPV. We utilized advanced machine learning and deep learning tools for epitope prediction, antigenicity assessment, and structural modeling (via AlphaFold2), and codon optimization. B-cell and T-cell epitopes were selected based on binding affinity, conservation, and immunogenicity, while adjuvants and linker sequences enhanced construct stability and immune response. In silico immune simulations forecasted robust humoral and cellular responses, including cytokine production and memory cell activation. The study also highlights challenges such as data quality, model interpretability, and ethical considerations. Our work demonstrates the transformative potential of AI in veterinary vaccinology and offers a scalable model for rapid, data-driven vaccine development against avian diseases. Full article