The development of an effective vaccine against noroviruses remains a major public health priority. Norovirus GII.4 capsid protein VP1 as a promising vaccine candidate was produced by the methylotrophic yeast Ogataea minuta production system. It was intracellularly expressed and subsequently purified by immobilized metal affinity chromatography and anion exchange chromatography, yielding 13.4 mg of highly purified VP1 protein from 50 mL of culture supernatant. The formation of VP1-based virus-like particles (VLPs) that retained their structure even after freeze-thawing was confirmed by transmission electron microscopy. The VP1 protein purified in the form of VLPs displayed strong antigenicity and specific, dose-dependent binding to histo-blood group antigens, as determined by the enzyme-linked immunosorbent assay (ELISA). Immunogenicity studies in BALB/c mice demonstrated that intramuscular administration induced robust serum IgG responses across all tested doses, with no significant dose-dependent differences. Furthermore, mucosal administration intranasally or sublingually induced systemic IgG, systemic IgA, and mucosal IgA responses. These responses were significantly enhanced by the lipid A adjuvant. These findings showed that the O. minuta production system is capable of producing immunogenic Norovirus VLPs as a vaccine candidate.

Assessment of genetic diversity and pathogenicity of porcine rotavirus A, and immunogenicity of a bivalent inactivated vaccine in southern China.

In silico profiling of the plasmodium knowlesi 32kDa antigen: Diversity, epitope prediction, and structural modeling.

A novel hypothetical protein (SAUSA300_1684) confers excellent protection against multi-drug-resistant Staphylococcus aureus infection in the murine model.

Development of duck hepatitis A virus type 1 attenuated vaccine E23-SP80 and its protective efficacy evaluation against DHAV-1 infection in ducks.

The Brucella abortus A19ΔfeuPΔfeuQ double-mutant is highly attenuated and confers protection in BALB/c mice.

Design and computational evaluation of a cross-protective multi-epitope vaccine candidate against Bartonella henselae and Bartonella clarridgeiae pathogens causing the zoonotic cat scratch disease in humans.

A novel mi3 VLP nanoparticle vaccine displaying ESAT-6 -PPE57 -PPE68 -EsxV antigens exhibits superior immunogenicity and Mycobacterium tuberculosis growth inhibition.

Poly(D,L-lactide-co-glycolide) nanoparticles significantly enhance the immunoprotective efficacy of Ascaridia galli excretory-secretory antigens.

Porcine circovirus type 2 (PCV2), the primary etiological agent of porcine circovirus-associated diseases (PCVADs), continues to cause substantial economic losses worldwide. Although commercially available vaccines have been widely deployed, they often fail to induce sufficient cellular immunity, which necessitates the development of improved vaccination strategies. This study reports the design and evaluation of a messenger RNA (mRNA)-based vaccine candidate targeting PCV2. The vaccine encodes the full-length capsid (Cap) protein, the principal target for neutralizing antibodies. For enhanced delivery and immunogenicity, the mRNA was encapsulated in lipid nanoparticles (LNP). Expression of the PCV2 Cap protein was confirmed in HEK-293T cells following transfection with the mRNA-LNP construct. In a mouse model, this vaccine elicited high titers of PCV2-specific IgG and potent virus-neutralizing antibodies, compared to a recombinant Cap subunit vaccine. Furthermore, the vaccine induced a robust Th1-polarized cellular immune response, marked by significant proliferation of antigen-specific CD8+ T cells and CD4+ T cells, enhanced interferon-gamma (IFN-γ) production, and expansion of T follicular helper cells and germinal center B cells in lymph nodes. Co-administration with a CpG ODN adjuvant further enhanced immunogenicity without compromising the vaccine's favorable safety profile. Collectively, these results indicate that the PCV2 mRNA-LNP vaccine represents a promising vaccine candidate worthy of further development against PCV2.IMPORTANCEPorcine circovirus type 2 (PCV2) is a widespread virus that causes severe disease in pigs, leading to significant economic losses in the swine industry worldwide. Existing vaccines often fail to stimulate strong cellular immunity, which is essential for long-lasting protection. In this study, we developed a novel messenger RNA (mRNA)-based vaccine encapsulated in lipid nanoparticles that encodes the PCV2 capsid protein. Our vaccine not only triggers potent antibody responses but also activates key immune cells, enhancing both humoral and cellular immunity. This represents the first mRNA-lipid nanoparticle vaccine against PCV2 and demonstrates the potential of mRNA technology to overcome limitations of traditional veterinary vaccines, offering a promising new tool for disease control in animals.

Dengue virus (DENV) continues to impose a global health burden, and virus-like particles (VLPs) are promising vaccine candidates, owing to their ability to elicit broadly neutralizing antibodies. However, the lack of nanoscale structural insights into the VLP maturation process has limited rational engineering. Here, we report the cryo-electron microscopy (cryo-EM) structure of immature DENV serotype 2 VLPs, revealing prM-E spikes arrayed on a T = 1 shell, consistent with mature DENV-2 VLPs and distinct from the virion, which exhibits a T = 3 icosahedral lattice. To connect the experimentally determined immature and mature endpoint structures, we employed a multiscale molecular dynamics (MD) framework to assess sterically feasible transition pathways. The simulations support the steric feasibility of a sliding-rotating rearrangement in which trimeric prM-E spikes reorganize into flat E dimers (E-E) without clashes. In virions, trimers reorganize into extended rafts of three parallel E dimers, whereas in VLPs, which lack the long-range symmetry and geometric constraints of the T = 3 lattice, maturation proceeds via a less extensive rearrangement in which neighboring monomers form small triangular clusters of three dimers. In addition, the simulations reveal pronounced lipid core mobility during maturation, including transient and spatially localized lipid protrusion events that preferentially occur near regions undergoing protein rearrangement, consistent with a potential role for dynamic membrane remodeling in accommodating maturation-associated structural changes. We also established a stable Chinese hamster ovary (CHO-K1) producer cell line, enabling efficient production of immature DENV serotype 2 VLPs. Together, this work defines a structure-dynamics framework that links steric feasibility, membrane composition, and particle stability and outlines process-relevant, testable hypotheses to inform future engineering of dengue VLPs that may ultimately guide vaccine design.

Bovine parainfluenza-3 virus (BPI3V) contributes to Bovine Respiratory Disease Complex, causing severe pneumonia and death in cattle, leading to economic losses. Existing BPI3V commercial vaccines, based on genotype A strains, confer protection against some, but not all, genotype A strains and induce low neutralizing antibody titers against genotypes B and C. This study aimed to develop a live vaccine capable of inducing broad protection against diverse BPI3V strains using an attenuated BPI3V vaccine vector based on a genotype C strain. A rescued recombinant BPI3VcmutantGFP virus exhibited a temperature-sensitive attenuated phenotype in vitro. Novel Fusion (designated F2) and Hemagglutinin-Neuraminidase (designated HN2) antigens, derived from consensus protein sequences of BPI3V genotypes A, B, and C, were used to develop a recombinant prototype vaccine, designated rBPI3VcmutF2-HN2. The recombinant virus replicated efficiently, displayed the novel antigens on the surface of infected cells, and remained stable over nine in vitro passages. Intranasal vaccination of calves with the rBPI3VcmutF2-HN2 virus induced strong systemic and mucosal IgG responses against BPI3V genotypes A, B, and C, which were significantly amplified upon boost, unlike the responses elicited by a commercial vaccine. Notably, sera from calves vaccinated with the rBPI3VcmutF2-HN2 virus had significantly higher (p<0.0001) neutralizing antibodies against BPI3V genotypes A-C compared to the commercial vaccine. The F2-HN2 antigens were critical in eliciting neutralizing antibodies against wild-type BPI3Va and c (p< 0.0001), and BPI3Vb (p<0.001). Upon challenge with wild-type BPI3V genotype C virus, the rBPI3VcmutF2-HN2-vaccinated calves shed the least amount of virus in nasal swabs, had lower viremia, and exhibited minimal pulmonary lesions. Therefore, rBPI3VcmutF2-HN2 virus is a promising vaccine candidate that has potential to confer broad protection against multiple BPI3V strains.

Dengue Virus Serotype 4 (DENV4) continues to contribute substantially to global dengue morbidity, yet current tetravalent vaccines provide inconsistent protection and may pose risks of antibody-dependent enhancement (ADE). This study aimed to design and evaluate a serotype-specific multi-epitope vaccine (MEV-DV4) targeting the conserved capsid protein of DENV4 using integrated reverse vaccinology and immunoinformatics approaches. Conserved, antigenic, non-allergenic, and non-toxic B-cell, cytotoxic T lymphocyte (CTL), and helper T lymphocyte (HTL) epitopes were identified and assembled with a β-defensin adjuvant and PADRE sequence using optimized linkers. The final construct demonstrated high antigenicity (0.8559), structural stability, favorable physicochemical properties, and excellent solubility. Structural validation confirmed 97.6% of residues in favored Ramachandran regions. Molecular docking revealed strong interactions with TLR4 and TLR8, particularly MEV-TLR8, and molecular dynamics simulations supported the overall stability of the complex. Immune simulations predicted robust humoral and cellular responses with strong memory formation. Experimental validation in an albino mouse model using an alum-adjuvanted MEV-DV4 formulation showed early and potent antibody responses, with peak HI titers at day 21. Notably, antibody titers induced by MEV-DV4 were statistically comparable to those produced by a commercial inactivated dengue vaccine at all tested time points (p > 0.05), while no adverse reactions were observed. These computational and experimental findings demonstrate that MEV-DV4 is a safe, immunogenic, and promising serotype-specific vaccine candidate against DENV4. Further neutralization and challenge studies are warranted to advance its preclinical development.

Sequential immunization is a promising approach to elicit broadly neutralizing antibodies (bNAbs) against the HIV-1 Envelope (Env). However, available protocols are inefficient and involve multiple immunizations over long periods of time. Here, we present WIN332, a new engineered Env immunogen that induces a new class of Asn332-glycan-independent antibodies to the conserved V3-glycan epitope of Env with low inhibitory activity indicative of a neutralization activity after a single bolus immunization in nonhuman primates. WIN332 binds to precursors of canonical human Asn332-glycan-dependent (type-I) V3-glycan bNAbs but also of a first-of-its-class Asn332-glycan-independent (type-II) V3-glycan bNAb. A single immunization elicits low inhibitory serum and monoclonal antibodies that are boosted and affinity matured with a heterologous immunogen. Electron microscopy polyclonal epitope mapping analysis of serum antibodies, antibody cloning and cryogenic electron microscopy analysis reveals that WIN332 elicits Asn332-glycan-independent antibodies with striking sequence and binding similarities with the most potent human type-I and type-II V3-glycan bNAbs. Thus, WIN332 is a promising vaccine candidate to streamline V3-glycan bNAb elicitation.

Genetic diversity, natural selection, and immunological features of the Plasmodium vivax CyRPA protein: Implications for vaccine development.

Robust immunoreaction induced by a subunit vaccine of PEDV spike protein based on GEM surface-display system.

mRNA vaccine for human cytomegalovirus in immunocompromised hosts: An immunoinformatics approach.

Coronaviruses remain a challenge due to the limited or incomplete protection provided by existing vaccines, highlighting the need for improved antigen-based designs that can reduce mortality, block transmission, and provide long-lasting, broad-spectrum protection. In this study, we adapted artificial antibody strategies to display receptor-binding domains (RBDs) from representative human coronaviruses, utilizing an engineered human IgG1 framework modified at the Fab and Fc domains to support diverse antigen presentation and enhanced immunopotentiation. The results indicate that bivalent, tetravalent, and multivalent RBD constructs developed within this framework confer broad-spectrum immune protection against severe acute respiratory syndrome coronavirus 2 and other pathogenic coronaviruses. Moreover, Fc-mediated antigen delivery, primarily engaging the neonatal Fcγ receptor, enhances mucosal, cellular, and sustained immune responses. This underscores the versatility and practical utility of the modified IgG1 framework, based on artificial antibody strategies, for developing broad-spectrum mucosal vaccine antigens, representing promising vaccine candidates targeting human coronaviruses.

The detection of Japanese encephalitis virus (JEV) genotype V (GV) in humans in Korea in 2015 has raised concerns regarding its potential public health impact. Current JEV vaccines, based on genotype Ⅲ (GⅢ) strains, exhibit suboptimal neutralizing activity against JEV GV, thereby underscoring the need for genotype-specific vaccines. To address this, we developed the KNIH (GV) vaccine strain optimized for enhanced production efficiency. We evaluated its neutralizing activity and protective efficacy in a murine model. The currently available GⅢ-based vaccine (Beijing-1 strain) exhibited limited neutralizing efficacy against JEV GV. Conversely, the KNIH-based vaccine elicited strong neutralizing responses against JEV GV but exhibited reduced cross-neutralization against JEV GⅢ. In conclusion, the K15P38-KNIH strain represents a promising vaccine candidate for mitigating the risk associated with JEV GV reemergence. Future studies will focus on evaluating the efficacy of bivalent vaccination strategies against other circulating JEV genotypes in Korea.

Short-lived, clade-specific immune responses with limited mucosal priming are limitations faced by current COVID-19 mRNA vaccines. We have developed a nasal booster vaccine candidate that induced robust, sustained, cross-clade, systemic and mucosal protective immunity. Two recombinant Clec9A-specific monoclonal antibodies fused to the Receptor Binding Domain (RBD) from Omicron XBB.1.5 and SARS-CoV-1, respectively were generated. In Comirnaty mRNA-vaccinated mice, boosting with both constructs combined (Clec9AOMNI) induced cross-clade neutralizing antibodies (nAbs) and T-cell responses that were greater in magnitude and more sustained compared to bivalent Comirnaty (BC) mRNA vaccine booster. Persistence of RBD-specific follicular helper CD4+ T cells, germinal centre B cells, and long-lived plasma cells that facilitated affinity maturation, correlated with detection of triple cross-reactive B cells binding the RBDs of SARS-CoV-2 ancestral, XBB.1.5, and SARS-CoV-1. Remarkably, intranasal boosting with Clec9AOMNI elicited robust and durable immunity across the upper and lower airways while concurrently boosting the systemic immunity to levels matching or exceeding those from systemic boosting. Correspondingly, Clec9AOMNI nasal booster conferred superior protection against SARS-CoV-2 challenge compared to BC mRNA booster, with undetectable viral titers in the respiratory tract. Hence, Clec9AOMNI is a promising nasal booster vaccine candidate that has the potential to mitigate pandemic threats from emerging sarbecoviruses.