Search Results (978)

Background: Virus-like particles (VLPs) represent key tools for the development of vaccines due to their ability to induce a potent immune response to epitopes presented on their surface. However, the decoration of VLPs with a complete heterologous protein on the surface remains a bottleneck for clinical translation due to the complexity of manufacture. We present a novel platform, EPIclip™, for the decoration of VLPs mediated by high-affinity protein binding partners, colicin E7 (ColE7) and immunity protein 7 (Im7), within a single prokaryotic host. We evaluate this approach using a modified hepatitis B core capsid protein and IL-31 as a model epitope. IL-31 is a prominent therapeutic target for the development of pruritic diseases. Methods: We explore the design and development of the platform, including the use of T-cell-stimulating peptides. We demonstrate several small-scale purification methods for the candidate VLP, as well as morphological analysis by transmission electron microscopy (TEM). Further, we vaccinate mice with IL-31-displaying VLPs to evaluate immunogenicity and the ability to prevent IL-31-induced pruritus in vivo. Results: Our results demonstrate that decorated VLPs dosed in mice elicit an IgG response against IL-31 with at least six months of durability. In addition, IL-31-displaying VLPs suppress the development of IL-31-induced pruritus, confirming in vivo target neutralisation. Notably, IL-31-displaying VLPs induce a strong T-cell response against the VLP capsid but not against the cytokine, confirming a B-cell-biased immune response and the absence of detrimental autoreactive T cells. We further demonstrate the translation of this system with an additional virus capsid: tomato aspermy virus (TAV). Conclusions: Taken together, the novel EPIclip™ platform may represent a promising therapeutic approach for pruritic diseases. Additionally, this modular system could be adapted for a wide range of research as well as human and veterinary therapeutic applications. Full article

Background/Objectives: Rabbit hemorrhagic disease (RHD) is an incurable, highly contagious disease caused by different RHD virus (RHDV) strains, such as the coexisting RHDV2 and classical RHDV. Disease control is based on vaccination using different or polyvalent vaccines. This study assessed the protective efficacy, onset of immunity (OOI), and duration of immunity (DOI) of a new recombinant vaccine containing a single active substance developed to target both strains: against RDHV2, highly virulent RDHV2 (hvRHDV2), and classical RDHV strains. Methods: This study included six randomized, controlled, blinded trials in clinically healthy New Zealand White rabbits. Rabbits were grouped to receive the recombinant vaccine or placebo (1:1 ratio) and challenged with RHDV2 (2¹⁵ hemagglutination [HA], infective dose; n = 39 for duration and n = 43 for onset), hvRHDV2 (2¹⁵ HA; n = 48 and n = 40), or classical RHDV (2¹² hemagglutination [HA], infective dose; n = 20 and n = 22) strains to evaluate OOI and DOI. Results: Rabbits receiving the vaccine showed a lower mortality than those receiving placebo upon challenge with any of the three strains. OOI trials showed that vaccinated rabbits exhibited higher levels of antibodies against RHDV2 than controls seven days post-vaccination. DOI trials revealed that, compared with controls, vaccinated rabbits had increased levels of antibodies against RHDV2 across all time points assessed, at least until the day of the viral challenge with any of the RHDV strains (approximately 12 months post-vaccination). Conclusions: This recombinant vaccine is the first to show a durable and robust protection against all tested strains, including the RHDV2, hvRHDV2, and classical RHDV strains, underscoring its potential as a comprehensive tool for RHD prevention. Full article

Mosquito-borne flaviviruses, including Dengue virus (DENV), Japanese encephalitis virus (JEV), West Nile virus (WNV), Yellow fever virus (YFV), and Zika virus (ZIKV), continue to present a significant threat to public health worldwide. In 2024, these viruses accounted for 11,717 reported cases in the United States and more than 7.6 million cases globally. As of early 2025, according to CDC data, 1830 cases of dengue had already been reported, with 1584 transmitted locally within the U.S. Despite the considerable burden that these diseases pose, no specific antiviral treatments exist. A very limited number of virus-specific vaccines have been licensed, such as those for YFV, JEV, and, with specific constraints, for DENV. To date, no pan-flavivirus vaccine is available. This review examines the potential of emerging vaccine platforms—particularly messenger RNA and virus-like particles—as promising tools in the pursuit of a broadly protective flavivirus vaccine. We analyze current strategies for inducing cross-neutralizing immune responses and discuss how these technologies could support the presentation of conserved quaternary epitope conformations, which are increasingly recognized as critical targets for establishing potent immune responses. We review key advances in virology, immune response, and immunogen delivery systems to highlight the potential for developing a pan-flavivirus vaccine. Full article

Gene editing technologies have revolutionized therapeutic development, offering potentially curative and preventative strategies for cardiovascular disease (CVD), which remains a leading global cause of morbidity and mortality. This review provides an introduction to the state-of-the-art gene editing tools—including ZFNs, TALENs, CRISPR/Cas9 systems, base editors, and prime editors—and evaluates their application in lipid metabolic pathways central to CVD pathogenesis. Emphasis is placed on targets such as PCSK9, ANGPTL3, CETP, APOC3, ASGR1, LPA, and IDOL, supported by findings from human genetics, preclinical models, and recent first-in-human trials. Emerging delivery vehicles (AAVs, LNPs, lentivirus, virus-like particles) and their translational implications are discussed. The review highlights ongoing clinical trials employing liver-targeted in vivo editing modalities (LivGETx-CVD) and provides insights into challenges in delivery, off-target effects, genotoxicity, and immunogenicity. Collectively, this review captures the rapid progress of LivGETx-CVD from conceptual innovation to clinical application, and positions gene editing as a transformative, single-dose strategy with the potential to redefine prevention and long-term management of dyslipidemia and atherosclerotic cardiovascular disease. Full article

Background/Objectives: Toxoplasma gondii (T. gondii) dense granule antigen 14 (GRA14) is a parasitophorous vacuole membrane protein that plays a critical role in the development of chronic-stage cysts. However, its potential as a vaccine antigen and long-term immunity have not been evaluated using a virus-like particle (VLP) platform. Methods: influenza matrix protein (M1)-based VLPs displaying GRA14 were generated. Female BALB/c mice were intranasally immunized with the VLP vaccine and orally challenged with lethal ME49 cysts either 10 weeks or 32 weeks after prime vaccination for short-term and long-term immunity evaluation, respectively. Results: GRA14 VLP vaccination elicited higher levels of T. gondii-specific IgG, IgG1, and IgG2a antibody responses in sera compared to non-immunized controls. Upon challenge infection, elevated IgG- and IgA-secreting plasma cells, germinal center B cells, and memory B cells were observed, and CD4⁺, CD8⁺ T-cells, as well as both Th1 (IFN-γ) and Th2 (IL-4, IL-5) cytokines, were also increased. For the short-term immunity study, vaccinated mice exhibited suppressed cerebral inflammation, significantly reduced brain cyst burdens, maintained stable body weight, and achieved 100% survival. For the long-term study, GRA14 VLPs sustained elevated IgG and IgG1 levels as well as conferred partial yet significant protection, with lower cyst loads and 83% survival. Conclusions: GRA14 VLPs induce durable, balanced humoral and cellular immunity and provide both short-term and long-term protection against lethal chronic toxoplasmosis, supporting their potential as promising vaccine candidates. Full article

Severe acute respiratory syndrome coronavirus (SARS-CoV) assembles and buds from the Golgi apparatus or the ER membrane, but the specific membrane microdomains utilized during this process remain underexplored. Here, we show that co-expression of the SARS-CoV structural proteins S, M, and N in HEK-293T cells is sufficient to generate genome-free SARS-CoV-like virus-like particles (VLPs), which preferentially bud from glycolipid-enriched membrane lipid raft microdomains. Immunofluorescence microscopy using raft-selective dyes (DiIC16) and spike-specific antibodies revealed strong co-localization of VLPs with lipid rafts. Detergent-resistant membrane analysis and sucrose gradient centrifugation further confirmed the presence of S protein in buoyant, raft-associated fractions alongside the raft marker CD44. Importantly, pharmacological disruption of rafts with methyl-β-cyclodextrin reduced VLP budding and S protein partitioning into raft domains, underscoring the requirement for intact lipid rafts in assembly. Additionally, our data support lipid raft-associated proteins’ (e.g., FNRA, VIM, CD59, RHOA) roles in modulating cellular responses conducive to viral replication and assembly. These findings highlight lipid rafts as crucial platforms for SARS-CoV morphogenesis and suggest new avenues for vaccine and antiviral development using VLPs and raft-targeting therapeutics. Full article

Background: Feline panleukopenia virus (FPV) causes acute and frequently fatal disease in cats, underscoring the urgent need for safe, rapidly effective, and scalable vaccines. While virus-like particle (VLP) vaccines are inherently safe and immunogenic, their development is constrained by low yields of recombinant protein in insect cell expression systems. Methods: An optimized baculovirus expression vector system (BEVS) incorporating the hr1-p6.9-p10 transcriptional enhancer and the Ac-ie-01 anti-apoptotic gene was employed to enhance recombinant protein production. VP2 expression levels, viral titers, and hemagglutination activity were quantified using qPCR, SDS-PAGE/Western blotting, transmission electron microscopy (TEM), and functional assays. Immunogenicity and protective efficacy were assessed in both mice and cats through serological analysis, neutralizing antibody detection, and post-challenge clinical monitoring. Results: The optimized BEVS enhanced recombinant protein transcription by 1.5-fold, viral titers by 3.7-fold, and hemagglutination activity by 15-fold. The purified protein self-assembled into uniform 25 nm virus-like particles (VLPs). Immunization elicited earlier responses compared to commercial vaccines. Vaccinated cats maintained normal body temperature, stable leukocyte counts, and minimal viral shedding following FPV challenge. Conclusions: This study validates an enhanced BEVS that effectively overcomes VP2 yield constraints and generates highly immunogenic FPV VLPs. The platform enables rapid-onset protection and offers a scalable strategy for next-generation FPV vaccine development. Full article

The COVID-19 pandemic accelerated vaccine innovation but also exposed weaknesses in global access and manufacturing. Yeast-based platforms, particularly Saccharomyces cerevisiae and Pichia pastoris, also known as Komagataella phaffii, offer a practical complement to vector systems. These eukaryotic microorganisms combine safety, scalability, and cost-effectiveness with the ability to express complex antigens and assemble virus-like particles. Building on the success of the recombinant hepatitis B vaccine, recent advances in glycoengineering, CRISPR-based host optimization, and surface display technologies have expanded the utility of yeast-based platforms for the rapid development of vaccines. Yeast-derived SARS-CoV-2 receptor-binding domain (RBD) subunit vaccines, such as Corbevax and Abdala (CIGB-66), demonstrate that affordable, immunogenic, and thermostable products are feasible at scale. Emerging innovations in glycan humanization, thermostable formulations, and oral or mucosal delivery highlight the potential of yeast-based vaccines for decentralized manufacturing and equitable pandemic preparedness. This review summarizes recent technical and clinical progress in yeast-based vaccine research, positioning these platforms as accessible and adaptable tools for future outbreak responses and global immunization strategies. Full article

Background: A quadrivalent HPV vaccine (BPV) has been developed to prevent diseases caused by HPV types 6, 11, 16, and 18 for the first time in Iran. The BPV is composed of the papillomavirus major capsid protein L1, which serves as the primary target in the design of the prophylactic HPV vaccines. To enhance immunogenicity, BPV was formulated with an amorphous aluminum hydroxy phosphate sulfate adjuvant. Methods: The immunogenicity and safety of BPV were assessed through analyses of both humoral and cell-mediated immunity, single and repeated doses, and reproductive effects using animal models. Results: Acute toxicity assessments showed no abnormalities in ophthalmic examinations, biochemical profiles, hematological parameters, and gross pathology findings. Additionally, no mortality or abnormal clinical signs were observed during a 90-day repeated-dose toxicity study. While some inflammatory reactions were noted at the injection sites and in the liver tissues of BPV-treated groups, these reactions were resolved by day 90 after the initial BPV administration. Furthermore, no signs of toxicity were detected in F1 offspring, and no adverse effects were identified in maternal reproductive performance, fertility, or hematological or biochemical parameters throughout the study duration. The BPV candidate successfully induced T-cell proliferation and increased the proportions of CD₃⁺ CD₄⁺ and CD₃⁺ CD₈⁺ T cells. It also stimulated the secretion of both interferon gamma (IFN-γ) and interleukin-4 (IL-4) cytokines in splenocytes isolated from animal models after the third dose. Moreover, anti-HPV L1 IgG antibody production was confirmed on day 14 after administration of each of the three BPV vaccine doses. Conclusions: The findings suggest that BPV is a vaccine candidate that stimulates both cellular and humoral immunity and demonstrate its safety profile in animal models. 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

Severe dengue virus (DENV) infections are associated with circulating non-neutralizing antibodies generated during heterotypic infections. Although antibodies are key mediators of both protection and pathogenesis, the specific dynamics of B cells (Bc) and their antibody responses remain insufficiently characterized due to limited methods of identifying DENV-specific Bc (DENV-Bc) and the absence of animal models resembling the human disease. Here, we developed a spectral flow cytometry assay employing biotinylated virus-like particles (VLPs) to detect DENV-Bc in C57BL/6 mice and children hospitalized with dengue. DENV-1 and DENV-2 VLPs were biotinylated, and the efficiency of biotin incorporation was assessed with an HABA-avidin assay and ELISA. Serotype specificity and optimal binding conditions were confirmed using hybridomas 4G2 (pan-flavivirus) and 3H5-1 (DENV-2 specific). Fluorescent agglutimers were subsequently generated by coupling biotinylated VLPs to streptavidin–fluorochrome complexes. Splenocytes from intraperitoneally DENV-infected mice and peripheral blood mononuclear cells (PBMCs) from naturally infected pediatric patients were stained with these VLPs and Bc-lineage markers. Biotinylated VLPs bound specifically to hybridomas, and this binding was competitively inhibited by unlabeled VLPs. After secondary DENV challenge, VLPs identified DENV-specific class-switched plasmablasts in mice. Circulating DENV-specific plasmablasts were also detected in children, with agglutimers enabling the discrimination of serotype-specific and cross-reactive responses in primary and secondary infections. This VLP-based approach represents a scalable platform to investigate the protective and pathogenic roles of DENV-Bc in infection and vaccination. Full article

Long Terminal Repeat (LTR) retrotransposons (LTR-RTEs) comprise up to 90% of some plant genomes and drive genome diversification through their amplification. Novel insertions arise during the final stages of the LTR-RTE life cycle, which depends on both LTR-RTE-encoded proteins and host cellular factors. The LTR-RTE elements require host transcriptional machinery for RNA production, followed by nuclear processing/export, translation, virus-like particle assembly, reverse transcription, and genomic integration. This review addresses the following question: What host proteins promote LTR-RTE transposition in plants? Our analysis of recent literature on host factors and cellular compartments implicated in the retrotransposition cycle reveals the extensive integration of LTR-RTEs into host processes. Nonetheless, the precise mechanisms remain poorly resolved, especially in plants with their rich repertoire of LTR-RTEs. We propose integrating plant mobilomics with transposition reporters, genome editing, synthetic biology, and interactomics to elucidate plant-specific mechanisms. Full article

Background: The R21 malaria vaccine is a next-generation, WHO-prequalified vaccine that was introduced to reduce the burden of clinical malaria. In alignment with WHO recommendations, multi-dose vaccine presentations are preferred for large-scale immunization and inclusion in the Expanded Programme on Immunization (EPI). Accurate protein quantification is a critical quality control parameter for lot release, but it remains challenging when the antigen is present at low protein concentrations or formulated with complex matrices, including adjuvants, stabilizers, and preservatives. Methods: In this study, multiple protein estimation methods including Micro-BCA, BCA, and Bradford assays were evaluated to determine their suitability for quantifying the R21 antigen formulated with Matrix-M1 adjuvant and 2-PE preservative. The Bradford assay was selected as the most appropriate method, based on a comparative assessment of precision, accuracy, and linearity. Further optimization was undertaken to identify suitable buffer systems, and the method was validated in accordance with ICH Q2(R2) guidelines. Results: Validation results demonstrated that the assay is specific, accurate, precise, and repeatable, with a limit of quantitation (LOQ) of 2 µg/mL. The method demonstrated comparable performance to ELISA and was found to be sensitive enough to detect changes in antigen concentration resulting from unintended adsorption of R21 to vial surfaces. The assay offers a rapid, high-throughput, and cost-effective solution for protein quantitation in commercial manufacturing, lot release, and stability studies. The protein content of the drug product, quantified using the Bradford method, demonstrated robust in vivo immunogenicity in both release and stability studies. Conclusions: The robustness and reproducibility of the assay establish a new benchmark in quality control for virus-like particle (VLP)-based vaccines with complex formulations, thereby supporting the precision and reliability required for global malaria prevention efforts. Full article

Background: Porcine circovirus type 2 (PCV2) remains one of the most important pathogens that infects swine, causing considerable economic losses worldwide. PCV2 vaccines are commercially available, and the development of experimental vaccines that could confer better protection against emerging genotypes is underway. The expression of virus-like particles (VLPs) carrying different PCV2 capsid (Cap) peptides in E. coli was recently reported. These chimeric particles were adjuvated with an oil-in-water emulsion with polymer and induced different titers of serum IgG in BALB/c mice after a single subcutaneous injection. The aim of this study was to assess the immune response and protective efficacy elicited by VLPs carrying the PCV2b Cap carboxy-terminal peptide in the target species. Methods: Domestic pigs (Sus scrofa domesticus) were immunized intramuscularly with 25 μg of adjuvated chimeric VLPs on days 0 and 14 and challenged on day 28 with a PCV2b Mexican isolate. PCV2 peptide-specific IgG seroconversion, serum cytokines, viral load in nasal swabs and organs, and histopathological score were determined. Results: IgG levels peaked 28 days post-immunization. Interleukin-12 and -18 and interferon-gamma increased 21 days after immunization. In addition, genomic material of PCV2 was detected in nasal swabs from one specimen on day 7, two specimens on day 14, and two specimens on day 21 following viral challenge. Finally, histological lesions were not less severe in immunized specimens compared to non-vaccinated/challenged specimens. Conclusions: These results suggest that immunization with chimeric VLPs could contribute to controlling viral shedding in pig herds where a PCV2b genotype is most prevalent. Full article

Dengue Virus (DENV) induces assembly of the NOD-like receptor (NLR) family pyrin domain containing-3 (NLRP3) inflammasome and autophagy, which are closely interconnected processes playing crucial roles in lipid metabolism and DENV replication. However, the autophagy–NLRP3 activation interplay during DENV infection in human endothelial cells remains incompletely understood. We aimed to elucidate effects of NLRP3 activation on autophagy during DENV-2 infection. We investigated how autophagy-related molecules are altered by NLRP3 inhibition and how this regulation affects lipid metabolism, through the master lipid transcription factors SREBP-1 and 2, which increase the expression of their target lipid-synthesizing genes such as fatty acid synthase (FAS) in a model of microvascular endothelial cells (HMEC-1). We demonstrated a dynamic interplay between inflammasome activity and autophagy in DENV-infected HMEC-1 cells: autophagy increases early during infection and decreases as inflammasome activity increases. NLRP3 inflammasome inhibition affects viral replication. Glyburide (an inflammasome inhibitor) treatment partially inhibited DENV-induced NLRP3 inflammasome activation. Non-structural viral protein expression (NS3 and NS5) and infectious viral-particle formation were significantly reduced. NLRP3 inhibition also downregulated SREBP-1 and SREBP-2 activation. These findings provide new insights into the modulation of the interconnected NLRP3 inflammasome, autophagy, and lipid metabolism pathways, presenting a promising therapeutic strategy for severe clinical forms of dengue. Full article