Search Results (761)

Background: Antigen format strongly influences the immunogenicity of gene-based vaccines. Full-length Spike is widely used in licensed COVID-19 vaccines, while truncated subunits such as S1 or the receptor-binding domain (RBD) may simplify vector design but risk reduced potency. We aimed to compare these antigen formats in an AAV9 delivery platform. Methods: BALB/c mice were immunized intramuscularly with recombinant AAV9 encoding full-length Spike, S1, or RBD at doses of 1 × 10¹⁰ or 1 × 10¹¹ viral genomes. Immune responses were assessed by serology, virus neutralization, T-cell profiling, and histopathology. Results: All constructs expressed antigen in vitro and in vivo. Only full-length Spike elicited robust neutralizing antibodies at both doses, with titers rising significantly by week 12. High-dose RBD induced neutralization in a minority of animals, whereas S1 failed to do so. Antigen-specific IgG responses scaled with insert length (Spike > S1 > RBD). Cellular immunity was dominated by CD8⁺ effector memory T cells, strongest in the Spike group, which also induced measurable CD4⁺ responses. Local transient myositis was observed at the injection site but resolved by week 24, with no systemic pathology. Conclusions: Full-length Spike outperforms truncated subunits in the AAV context, highlighting antigen structure as a critical factor for next-generation coronavirus vaccine design. Full article

Background/Objectives: Flaviviruses, including West Nile virus (WNV), pose global health challenges due to their worldwide distribution, pathogenicity, and lack of effective treatments or vaccines. Today, WNV is considered the most important causative agent of viral encephalitis worldwide. This study investigated the different forms of the main WNV antigen—the preM/E protein—in the context of its immunogenic and protective properties. Methods: The recombinant adenovirus type 2 (rAd2) vectors expressing different forms of the WNV preM/E genes were obtained using standard molecular biology techniques. Immunogenicity in mice was assessed by enzyme-linked immunosorbent assay (ELISA) and virus neutralization assay. Immunological efficacy was evaluated in a mouse viral challenge model. Results: The rAd2 vector expressing the West Nile virus preM/E gene with mutations in the fusion loop exhibited robust immunogenicity when administered intramuscularly either once or in a homologous prime-boost regimen. This antigen form, as part of an adenoviral vector, protected mice from death in viral challenge experiments, providing 100% survival following WNV challenge. Conclusions: We believe that a vaccination strategy involving a recombinant adenoviral vector based on human adenovirus type 2 and the WNV antigen represented by the preM/E gene with mutations in the fusion loop may be a promising approach for combating West Nile virus infection. Full article

Viral hepatitis constitutes a substantial global public health challenge. The etiological agents, referred to as hepatitis viruses, are primarily categorized into five types: hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), and hepatitis E virus (HEV). Among the various preventive strategies, vaccination is widely acknowledged as the most cost-effective and efficient method for controlling viral hepatitis and its related hepatic complications. To date, numerous countries have initiated extensive vaccination programs targeting hepatitis A and hepatitis B. Advances in biotechnology have facilitated substantial progress in vaccine formulation design, the development of innovative adjuvants, and the utilization of novel vectors. However, significant challenges persist, including inadequate vaccination coverage, inconsistent immune responses among vulnerable populations, and concerns regarding vaccine safety. This article presents a systematic review of recent advancements, the current status of vaccination efforts, and ongoing challenges associated with hepatitis vaccines, with the objective of providing critical insights to support the World Health Organization’s goal of eliminating viral hepatitis as a public health threat by 2030. Full article

Seasonal human coronaviruses (HCoVs), including HCoV-229E, HCoV-NL63, HCoV-OC43, and HCoV-HKU1, circulate globally in an epidemic pattern and account for a substantial proportion of common cold cases, particularly in infants, the elderly, and immunocompromised individuals. Although clinical manifestations are typically mild, these HCoVs exhibit ongoing antigenic drift and have demonstrated the potential to cause severe diseases in certain populations, underscoring the importance of developing targeted and broad-spectrum vaccines. This review systematically examines the pathogenesis, epidemiology, genomic architecture, and major antigenic determinants of seasonal HCoVs, highlighting key differences in receptor usage and the roles of structural proteins in modulating viral tropism and host immunity. We summarize recent advances across various vaccine platforms, including inactivated, DNA, mRNA, subunit, viral-vectored, and virus-like particle (VLP) approaches, in the development of seasonal HCoV vaccines. We specifically summarize preclinical and clinical findings demonstrating variable cross-reactivity between SARS-CoV-2 and seasonal HCoV vaccines. Evidence indicates that cross-reactive humoral and cellular immune responses following SARS-CoV-2 infection or vaccination predominantly target conserved epitopes of structural proteins, supporting strategies that incorporate conserved regions to achieve broad-spectrum protection. Finally, we discuss current challenges in pathogenesis research and vaccine development for seasonal HCoVs. We propose future directions for the development of innovative pan-coronavirus vaccines that integrate both humoral and cellular antigens, aiming to protect vulnerable populations and mitigate future zoonotic spillover threats. Full article

Influenza viruses remain a major global public health concern, causing significant morbidity and mortality annually despite widespread vaccination efforts. The limitations of current seasonal vaccines, including strain-specific efficacy and manufacturing delays, have accelerated the development of next-generation candidates aiming for universal protection. This review comprehensively summarizes the recent progress in universal influenza vaccine research. We first outline the key conserved antigenic targets, such as the hemagglutinin (HA) stem, neuraminidase (NA), and matrix proteins (M2e, NP, and M1), which are crucial for eliciting broad cross-reactive immunity. We then delve into advanced antigen design strategies, including immunofocusing, multi-antigen combinations, computationally optimized broadly reactive antigens (COBRA), and nanoparticle-based platforms. Furthermore, we evaluate evolving vaccine delivery systems, from traditional inactivated and live-attenuated vaccines to modern mRNA and viral vector platforms, alongside the critical role of novel adjuvants in enhancing immune responses. The convergence of these disciplines—structural biology, computational design, and nanotechnology—is driving the field toward a transformative goal. We conclude that the successful development of a universal influenza vaccine will likely depend on the strategic integration of these innovative approaches to overcome existing immunological and logistical challenges, ultimately providing durable and broad-spectrum protection against diverse influenza virus strains. Full article

Bovine parainfluenza virus type 3 (BPIV3) is a significant pathogen implicated in bovine respiratory disease complex (BRDC), leading to lung tissue destruction, immunosuppression, and subsequent bacterial infections in cattle, hence incurring considerable economic losses globally. Notwithstanding its importance, a limited number of commercial vaccinations are presently accessible. The fusion (F) protein and hemagglutinin-neuraminidase (HN) protein, as protective antigens of the Paramyxoviridae family, can elicit neutralizing antibodies and are regarded as optimal candidates for the creation of genetically modified vaccines. A multi-epitope-based peptide vaccine (MEBPV) was developed by immunoinformatics methodologies by choosing epitopes from the F and HN proteins characterized by high antigenicity, moderate toxicity, and limited allergenic potential. The epitopes were combined with suitable linkers and adjuvants to produce the vaccine, whose physicochemical qualities, immunological attributes, solubility, and structural stability were improved and evaluated using computational methods. Molecular docking and molecular dynamics simulations demonstrated the strong potential binding affinity and stability of the vaccination with TLR2, TLR3, and especially TLR4 receptors. Immune simulations forecasted strong humoral and cellular responses, accompanied by a significant elevation in interferon-γ (IFN-γ) production. The vaccine sequence was later cloned into the pET-28a (+) vector for possible expression in Escherichia coli. Despite in silico predictions suggesting a favorable immunogenic potential, additional in vitro and in vivo studies are necessary to confirm its protective efficacy and safety. This research establishes a solid foundation for the creation of safe and efficacious subunit vaccines targeting BPIV3 and presents novel perspectives for the formulation of vaccinations against additional viral infections. Full article

West Nile Virus (WNV), a mosquito-borne flavivirus first identified in Uganda in 1937, has emerged over the past quarter century as a major global public health threat. Since its introduction into North America in 1999, WNV has become the leading cause of arboviral neuroinvasive disease, with recurrent outbreaks continuing across Europe, Africa, and the Americas. This review provides a comprehensive overview of the microbiology, epidemiology, and clinical impact of WNV. We discuss the molecular biology of the virus, highlighting its genomic organization, replication strategies, and the structural and non-structural proteins that underpin viral pathogenesis and immune evasion. The complex enzootic transmission cycle, involving Culex mosquitoes and diverse avian reservoir hosts, is examined alongside ecological and climatic determinants of viral amplification and spillover into humans and equines. The clinical spectrum of WNV infection is outlined, ranging from asymptomatic seroconversion to West Nile fever and life-threatening neuroinvasive disease, with particular emphasis on risk factors for severe outcomes in older and immunocompromised individuals. Current approaches to diagnosis, supportive management, and vector control are critically reviewed, while challenges in vaccine development and the absence of effective antiviral therapy are underscored. Finally, we address future research priorities, including therapeutic innovation, predictive outbreak modeling, and genomic surveillance of viral evolution. WNV exemplifies the dynamics of emerging zoonotic diseases, and its persistence underscores the necessity of a coordinated One Health approach integrating human, animal, and environmental health. Continued scientific advances and public health commitment remain essential to mitigate its enduring global impact. Full article

Duck enteritis virus (DEV), an epornitic pathogen, causes substantial economic losses in the commercial duck industry and poses persistent risks to wild and migratory waterfowl populations. However, due to the large genomic capacity of the DEV, the understanding of the virulence-associated genes of DEV is still limited. In previous studies, we developed an attenuated strain E74 by serial passage of a virulent strain E1 on primary chicken embryo fibroblasts (CEFs). The bird experiment showed that the mortality rate of E1 on ducks reached 100%, and high-titered viruses were detected in all tested tissue samples. In contrast, the E74 virus has lost its pathogenicity in ducks and can only be detected at a relatively low viral load in the spleen. Furthermore, the E74 stimulated a significant increase in antibodies in the ducks at 7 days post-inoculation. To further investigate the molecular basis of the attenuation of DEV in ducks, the complete genomes of E74 and E1 were sequenced and analyzed. Compared with E1, E74 had a 5152 bp deletion in the UL region, which resulted in the lack of the hypothetical protein, LORF5, UL55 and LORF4 genes. To test the influence of the deletion on the viral pathogenicity, a rescued virus rE1-Δ5152 with the 5152 bp deletion in the UL region was generated on the E1 backbone. Animal experiments showed that the lethality of rE1-Δ5152 in ducks had disappeared. Those findings suggest that the hypothetical protein, LORF5, UL55, and LORF4 genes of DEV are associated with virus virulence, and the flexibility of this region provided excellent insertion sites for exogenous genes when DEV is used as a recombinant vaccine vector. 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

COVID-19 vaccination has played a pivotal role in mitigating the global health crisis and reducing morbidity and mortality associated with SARS-CoV-2 infection. While its public health benefits are unequivocal, the unprecedented scale of vaccination—reaching billions worldwide—has also enabled the detection of rare autoimmune events, including systemic lupus erythematosus, rheumatoid arthritis, type 1 diabetes, and Guillain–Barré syndrome. Although such events occur in only a small subset of individuals, often influenced by genetic, environmental, or dosage-related factors, they underscore the importance of understanding immune tolerance mechanisms in vaccination. This review synthesizes clinical observations and immunological findings from the COVID-19 vaccination era, highlighting key mechanisms such as molecular mimicry, adjuvant-induced inflammation, bystander activation, epitope spreading, and polyclonal B cell activation. We also consider how novel vaccine platforms, particularly mRNA-based technologies, may influence immune regulation and self-tolerance. Importantly, we discuss the therapeutic management of vaccine-associated autoimmunity, including the use of corticosteroids, intravenous immunoglobulin (IVIG), plasma exchange, disease-modifying anti-rheumatic drugs (DMARDs), and other immunosuppressive agents, many of which have led to favorable clinical outcomes. By integrating mechanistic insights with treatment strategies, this review emphasizes that the overall benefits of COVID-19 vaccination overwhelmingly outweigh the risks, while advocating for continued surveillance, mechanistic research, and risk stratification to inform safer and more targeted vaccination strategies in future pandemics. Full article

Peste des petits ruminants (PPR) is a highly contagious viral disease that affects goats and sheep, causing severe clinical signs, high mortality, and significant economic losses in many developing countries. Pakistan is one of the endemic regions where PPR outbreaks caused by the Asian lineage IV virus have been reported frequently, affecting the livelihoods of millions of smallholder farmers who depend on these animals for food security and income generation. In this review, we provide a comprehensive overview of the current status, challenges and prospects for vaccine development against PPR in Pakistan. We discuss the epidemiology, diagnosis, and control of PPR in Pakistan, as well as the existing vaccines based on the attenuated strains and their limitations, such as low thermostability, short shelf life, and inability to differentiate between infected and vaccinated animals. We also highlight the recent advances in vaccine research and development, such as recombinant and vectored vaccines, thermostable formulations, and novel delivery methods that could overcome these limitations and enhance the immunogenicity and safety of PPR vaccines. We review the current and potential strategies for vaccine deployment, such as mass vaccination, targeted vaccination, ring vaccination, and their implications for the global eradication of PPR by 2030. We conclude by providing some recommendations for future research and development to improve vaccine efficacy, safety, and coverage in Pakistan, as well as to monitor the impact of vaccination on PPR incidence and prevalence. Full article

Cervical cancer remains a major public health concern, particularly in low- and middle-income countries (LMICs) where access to preventive measures is limited. Persistent infection with high-risk human papillomavirus (HPV) types, mainly HPV16 and HPV18, is the key cause of cervical cancer. While prophylactic HPV vaccines effectively prevent new infections, they offer no therapeutic benefit for individuals with established lesions. This review evaluates the clinical evidence on therapeutic HPV vaccines, focusing on their ability to promote viral clearance. A bibliographic search was conducted in PubMed, selecting human studies reporting outcomes on HPV clearance. Seventeen clinical trials were identified, including DNA-based (VGX-3100, GX-188E), viral-vector (MVA E2, TG4001), peptide-based (Pepcan), and bacterial-vector (GLT 001) vaccines. Among them, DNA-based vaccines, particularly VGX-3100, showed the most consistent results, whereas several protein- or vector-based approaches demonstrated variable outcomes. Early therapeutic HPV vaccine trials faced setbacks due to limited efficacy, delivery approaches, and study design challenges, preventing progression to late-phase development. Recent DNA-based candidates, however, are advancing through phase II/III trials. While none have yet to be approved for commercial use, these vaccines elicit virus-specific T-cell responses and can induce regression of precancerous lesions, offering a promising addition to prophylactic vaccination and screening. Variability in study designs and endpoints underlines the need for standardized protocols and further phase III trials. Overall, therapeutic HPV vaccines represent a rapidly advancing field with the potential to complement prophylactic vaccination and screening, thereby strengthening global cervical cancer control efforts, particularly in LMICs. Full article

The focus of this study was to explore phage display systems employing bacteriophage lambda (λ) gene fusions to its capsid decoration protein gpD as reagent tools for tackling disease. The biological activity of gpD-fusions was examined by testing for the retained antimicrobial toxicity of cathelicidins or defensins fused to gpD. Our previous finding that only COOH fusions of either cathelicidins or defensins to gpD were toxigenic was expanded to show that only the reduced form of fused defensin antimicrobial polypeptides was found to be toxigenic. Compared in review are gene-fusion lytic display systems (where the fusion-display gene is integrated within the viral genome) with a surrogate system, employed herein, that exogenously provides the fusion-display protein for addition to phage capsid. It is easily possible to produce fully coated lambda display particles (LDP) serving as single epitope vaccines (SEV), or antimicrobials, or to produce partially coated LDP without any complex bacteriophage genetic engineering, making the system available to all. The potential to build vaccine vector phage particles (LDNAP) comprising essentially sheathed DNA vaccines encapsulated within an environmentally protective capsid is described. LDNAP are produced by introducing a cassette into the phage genome either by phage–plasmid recombination or cloning. The cassette carries a high-level eukaryotic expression promoter driving transcription of the vaccine candidate gene and is devoid of plasmid resistance elements. Full article

Brucellosis remains one of the most significant zoonotic diseases, posing a serious threat to both human health and livestock. This issue is particularly relevant for Kazakhstan, which is among the countries endemic for brucellosis with a high incidence rate. Such circumstances highlight the urgent need for the development and implementation of effective preventive measures, including modern vaccine platforms capable of providing reliable protection for the population and reducing the economic impact on the agricultural sector. Recombinant capripoxviruses are considered promising vector platforms for vaccine development, as they ensure high expression of target antigens, elicit strong immune responses, and are safe for humans. In this study, the replication of recombinant capripoxviruses expressing Brucella antigens (SPPV (TK-) OMP19/SODC and SPPV (TK-) OMP25) was evaluated in Vero cells using the BelloStage™-3000 bioreactor system in combination with BioNOC II^® macrocarriers. Application of the bioreactor resulted in nearly a 100-fold increase in Vero cell density compared with static cultures and provided optimal conditions for cell adhesion, growth, and metabolic activity. Consequently, a significant increase in viral titers was observed: for SPPV (TK-) OMP19/SODC, mean titers reached 7.50 log₁₀ TCID₅₀/mL versus 4.50 in static culture (p < 0.0001), while SPPV (TK-) OMP25 achieved 7.08 log₁₀ TCID₅₀/mL versus 4.33 (p < 0.001). These findings confirm the reliability, reproducibility, and scalability of this bioreactor-based approach, demonstrating clear advantages over conventional cultivation methods. Overall, the study highlights the high potential of the BelloStage™-3000 system with BioNOC II^® macrocarriers for the industrial production of recombinant capripoxvirus-based vaccines against brucellosis and for the broader development of other recombinant viral vaccines. Full article

Preventive immunology is emerging as a cornerstone of animal infectious disease control within One Health, shifting emphasis from treatment to prevention. This review integrates mechanistic insights in host immunity with a comparative evaluation of next-generation interventions—mRNA/DNA and viral-vector vaccines, nanovaccines, monoclonal antibodies, cytokine modulators, probiotics/postbiotics, bacteriophages, and CRISPR-based approaches—highlighting their immunogenicity, thermostability, delivery, and field readiness. Distinct from prior reviews, we appraise diagnostics as preventive tools (point-of-care assays, biosensors, MALDI-TOF MS, AI-enabled analytics) that enable early detection, risk prediction, and targeted interventions, and we map quantifiable links between successful prevention and reduced antimicrobial use. We embed translation factors—regulatory alignment, scalable manufacturing, workforce capacity, equitable access in LMICs, and public trust—alongside environmental and zoonotic interfaces that shape antimicrobial resistance dynamics. We also provide a critical analysis of limitations and failure cases: gene editing may require stacked edits and concurrent vaccination; phage programs must manage host range, resistance, stability, and regulation; and probiotic benefits remain context-specific. Finally, we present a risk–benefit–readiness framework and a time-bound research agenda to guide deployment and evaluation across animal–human–environmental systems. Coordinating scientific innovation with governance and ethics can measurably reduce disease burden, curb antimicrobial consumption, and improve health outcomes across species. Full article