Search Results (264)

Background/Objectives: COVID-19, caused by the SARS-CoV-2 virus, can lead to widespread neurological and cognitive complications, even in the absence of significant structural brain abnormalities. Understanding the evolving health concerns in the context of viral infections is critical to service member readiness, fitness, and mission completion. The potential neuroprotective effects of SARS-CoV-2 vaccination remain underexplored. Methods: Using a cross-sectional, non-human primate model (female cynomolgus macaques), we employed magnetoencephalography (MEG) to assess resting-state brain activity following vaccination with escalating doses of a novel psoralen-inactivated SARS-CoV-2 vaccine (PsIV) or a combination of PsIV and a DNA vaccine (prime boost), and subsequent challenge with the Delta variant (SARS-CoV-2 B.1.617.2). MEG scans were acquired 41 days after inoculation. Source series were constructed for 42 regions of interest for each subject, and band power was computed. Results: Band power demonstrated substantial preservation of neural activity across multiple brain regions in vaccinated subjects compared to unvaccinated controls following viral challenge. Significantly lower power was observed across the brain at all bandwidths in the unvaccinated group relative to the prime boost group. As PsIV concentration increased, spectral power increased, with the prime boost group having the greatest power. Conclusions: This approach not only underscores the role of vaccination in mitigating neuropathology but also highlights the capability of MEG to detect subtle yet significant changes in brain function that may be overlooked by other imaging modalities. These findings advance our understanding of vaccine-induced neuroprotection and establish MEG as a powerful tool for monitoring brain function in the context of viral infections. Full article

To address the lack of a commercially available vaccine for goose circovirus (GoCV), we developed and evaluated a prokaryotically expressed subunit vaccine targeting the viral capsid (Cap) protein. A truncated Cap protein (GoCV-ΔCap) was expressed in Escherichia coli (E. coli) and formulated with aluminum hydroxide as a subunit vaccine (GoCVsubvac). Goslings were primed intramuscularly (i.m.) with high (75 µg) or low (15 µg) doses GoCVsubvac, followed by a boost 14 days later. At 14 days post-boost, goslings were challenged with GoCV and were administered a bivalent inactivated vaccine against Newcastle disease virus (NDV) and H9-subtype Avian influenza virus (AIV). Using our established gosling pathogenicity model, vaccine efficacy was evaluated via body weight, lesions, viral load, antibody titers, cytokine responses, and interference with NDV/AIV immunity. Results demonstrated that the GoCV-ΔCap vaccine, especially the high-dose formulation, provided effective immunoprotection. It elicited robust humoral and cellular immune responses, reduced lymphoid pathology, and decreased the viral detection rate in lymphoid tissues from 100% (5/5) in infected controls to 40% (2/5). Importantly, it alleviated GoCV-induced immunosuppression and preserved the immunogenicity of co-administered vaccines. This novel subunit vaccine is a promising candidate for controlling GoCV disease (GoCVD). Full article

Messenger RNA (mRNA) vaccines are emerging as promising tools capable of reshaping how cancer interacts with the immune system and responds to immunotherapy. These vaccines not only act as platforms for antigen delivery but can also influence the tumor microenvironment (TME), fostering a shift from immunologically “cold’’ conditions toward “hotter’’ and treatment-responsive states. In melanoma, this capability has been found to enhance the efficacy of the immune checkpoint inhibitors (ICIs), as mRNA-based priming can provide the robust antitumor activation needed for more effective checkpoint blockade. Early clinical studies with personalized or off-the-shelf vaccines showed benefits in patients with high-risk resected melanoma or refractory to PD-1 inhibition. Combining mRNA vaccines with ICIs, along with other immunomodulatory strategies, may be helpful to overcome resistance arising from the TME and achieve more durable clinical benefits. Besides these advances, computational and in silico modeling are providing new insights into how mRNA vaccines modulate the TME, helping to identify factors such as antigen-presenting cell (APC) density, CD8⁺ T-cell infiltration, and macrophage polarization that may predict treatment success and guide personalized strategies. Together, these developments indicate that combining mRNA vaccination with ICIs, supported by computational tools, may improve clinical outcomes in melanoma and, potentially, in selected tumor types with favorable immunological features, although important biological constraints limit direct extrapolation to less immunogenic malignancies. Full article

Pancreatic ductal adenocarcinoma (PDAC) remains highly lethal and largely refractory to immune checkpoint inhibition because limited antigen-specific priming, myeloid suppression, dense desmoplasia, and abnormal vasculature enforce immune exclusion. CD40 links CD4+ T-cell help through CD40L/CD154 to antigen-presenting-cell (APC) licensing and CD8+ T-cell priming, making CD40 agonism a rational strategy to stimulate antitumor immunity in PDAC. CD40 is expressed on APCs and has also been reported on subsets of PDAC tumor cells, cancer-associated fibroblasts, and endothelial cells, indicating that CD40 agonists may affect immune activation, stromal/vascular remodeling, and context-dependent tumor-cell-intrinsic signaling. TRAF-dependent CD40 signaling activates canonical and non-canonical NF-kB, MAPK, and PI3K/AKT pathways, promoting APC maturation, IL-12-associated Th1 programming, macrophage repolarization, and matrix remodeling; tumor-intrinsic effects remain more variable, ranging from apoptotic to pro-survival programs. Clinically, CD40 agonists have shown pharmacodynamic immune engagement and manageable toxicity, mainly in combinations with chemotherapy, checkpoint inhibitors, and vaccine platforms, but efficacy remains inconsistent, and randomized validation is incomplete. Baseline CD40 expression has not reliably predicted benefit. Future development should prioritize spatially resolved tumor-immune profiling, longitudinal pharmacodynamic biomarkers, optimized sequencing, and agent-specific dosing strategies. This review integrates CD40 expression, signaling, and clinical evidence in PDAC to support more rational, biomarker-guided development of CD40-directed immunotherapy. Full article

Therapeutic cancer vaccines represent a rational immunotherapeutic strategy aimed at inducing tumor-specific adaptive immune responses in patients with established malignancies. In contrast to prophylactic vaccines, these approaches must function within immunosuppressive tumor microenvironments characterized by antigenic heterogeneity, immune dysfunction, and dynamic tumor evolution. Effective vaccine design requires the integration of three essential components: the selection of appropriate tumor-associated or tumor-specific antigens, efficient delivery platforms that enable antigen presentation, and adjuvant systems that promote robust T-cell priming and expansion. Initial clinical investigations in B-cell malignancies and multiple myeloma demonstrated that idiotype-based vaccines can elicit tumor-specific immune responses. However, durable clinical benefit has been inconsistent, reflecting limitations in antigen selection, suboptimal immunogenicity, and tumor-mediated immune evasion. Over the past decade, advances in tumor genomics, next-generation sequencing, and immune monitoring have enabled the development of next-generation vaccine platforms, including dendritic cell-based approaches, personalized neoantigen vaccines, and mRNA-based technologies. Emerging evidence suggests that vaccine efficacy is highly dependent on disease context. Biologically favorable settings such as minimal residual disease (MRD) and post-transplant immune reconstitution provide reduced tumor burden and improved immune competence, thereby enhancing the likelihood of effective immune priming. In parallel, combination strategies incorporating immune checkpoint inhibitors, immunomodulatory agents, and cellular therapies are increasingly being explored to overcome tumor-induced immunosuppression. This review synthesizes current knowledge of therapeutic cancer vaccines in B-cell malignancies and multiple myeloma, with emphasis on immunologic mechanisms, antigen selection, vaccine platforms, and clinical evidence. We further propose a conceptual framework integrating tumor biology, immune context, and combination strategies to guide the rational development of next-generation vaccine therapies. Full article

Vaccination represents the cornerstone of Newcastle disease control. Nanotechnology offers a promising approach to improve the effectiveness of DNA vaccines, supporting their use as an alternative to conventional platforms. Herein, the Avian Orthoavulavirus 1 (AOAV-1) fusion (F) gene was cloned into a DNA expression plasmid (pDNA). After validating the constructed pDNA-F and confirming robust intracellular protein expression in vitro, three polymeric nanoparticles (NPs)-based formulations were generated using Chitosan (Cs), poly(lactic-co-glycolic) (PLGA), and poly(amidoamine) (PAMAM)-Dendrimers. Physicochemical characterization, stability assessment, and in vitro release analysis confirmed nanoparticle formation and effective DNA incorporation. In vivo experiments were conducted to comparatively evaluate the immunogenicity, particularly the immune priming capacity, and protective efficacy of nanoparticle-based formulations and naked pDNA-F, all tested in parallel at standardized pDNA doses via intranasal (IN) and intramuscular routes. PAMAM-Dendrimers-pDNA-F IM group demonstrated superior efficacy, with 100% survival, the highest post-challenge anamnestic antibody titers, and a pronounced reduction in viral RNA shedding. PLGA-NPs-pDNA-F IN group demonstrated enhanced efficacy, with 90% survival. Naked pDNA-F surpassed the Cs-NPs-pDNA-F in both immune priming and clinical protection, with Cs-NPs-pDNA-F exhibiting the lowest overall performance. These findings highlight that DNA vaccine performance depends on both carrier type and administration route, with PAMAM dendrimers and PLGA enhancing efficacy, whereas chitosan demonstrated reduced efficacy under the tested conditions. Full article

The Bacillus Calmette–Guérin (BCG) vaccine, originally developed for tuberculosis (TB) prevention, has recently attracted attention due to its broader immunomodulatory properties. In addition to its role in TB control, BCG induces trained immunity, a process involving epigenetic and metabolic reprogramming of innate immune cells that leads to altered systemic inflammatory responses. Increasing evidence suggests that these long-term immune adaptations may influence the central nervous system by modulating microglial activation and neuroinflammatory pathways implicated in neurodegenerative diseases. In parallel, chronic infections such as TB are associated with persistent systemic inflammation and immune dysregulation, which may contribute to microglial priming and increased vulnerability to neurodegeneration. This narrative review, based on a targeted literature search of PubMed, Scopus, Web of Science, Embase, and relevant preprint servers, synthesizes current evidence on the relationships between BCG vaccination, trained immunity, and neuroimmune interactions. We focus on studies addressing systemic immune reprogramming, microglial responses, and neuroinflammatory mechanisms relevant to neurodegenerative disorders. The available data suggest that BCG-induced immune modulation may exert context-dependent effects on the brain, with potential neuroprotective implications under certain conditions. However, the evidence remains heterogeneous and largely observational, and causality cannot yet be established. Further mechanistic and prospective studies are required to clarify whether BCG-induced trained immunity can modify the risk or progression of age-related neurodegenerative diseases. Full article

Toxoplasma gondii is an obligate intracellular protozoan parasite that causes toxoplasmosis, posing a significant threat to human health and livestock production worldwide. Although monovalent DNA or mRNA vaccines often confer only partial protection, whether these platforms can be effectively integrated into a heterologous prime–boost regimen against T. gondii remains to be fully elucidated. Here, we constructed GRA35-encoding DNA and mRNA vaccines and evaluated their immunogenicity and protective efficacy, administered either alone or in heterologous prime–boost combinations, in C57BL/6 and BALB/c mice. Both vaccines induced strong antigen-specific immune responses, with the heterologous prime–boost regimen eliciting the strongest effects and conferring the most robust and consistent protection across both mouse strains. Immunization triggered a predominantly Th1-skewed response characterized by significantly elevated IFN-γ production, accompanied by balanced antigen-specific IgG responses. Moreover, vaccinated mice developed rapid and potent cytotoxic T lymphocyte (CTL) responses. Following challenge with the RH and PRU strains, vaccinated mice exhibited prolonged survival and significantly reduced brain cyst burdens following PRU challenge compared with control groups. Collectively, these findings indicate that GRA35-based nucleic acid vaccines, particularly when administered in a heterologous prime–boost regimen, elicit multifaceted protective immune responses and represent promising vaccine candidates against T. gondii infection. Full article

Background: Currently marketed hepatitis B vaccines are primarily recombinant protein vaccines. However, their antigen immunogenicity is relatively weak, requiring combination with effective adjuvants to enhance the immune response. The development of novel, highly effective adjuvants is a key strategy for optimizing vaccine performance. Polyinosinic-polycytidylic acid (PolyI:C), a synthetic double-stranded RNA analog, activates TLR3/RLR pathways to enhance T-cell priming and cellular immunity. However, its utility as a sole adjuvant is limited by rapid nuclease degradation and poor cytosolic delivery. Lipid nanoparticles (LNPs), a mature delivery platform, enable high encapsulation efficiency, efficient cellular uptake, and endosomal escape. Objectives: This study aimed to evaluate the adjuvant effect of LNP-encapsulated PolyI:C (LNP-PolyI:C) on the immunogenicity of hepatitis B surface antigen (HBsAg) in vivo. Methods: The colloidal stability of LNP-PolyI:C stored at 2–8 °C for 9 months was monitored using dynamic light scattering (DLS) on a Zetasizer Lab instrument. Serum levels of HBsAg-specific IgG, IgG1, and IgG2a antibodies in immunized Kunming mice were measured by enzyme-linked immunosorbent assay (ELISA). The secretion of HBsAg-specific cytokines by splenocytes was analyzed using flow cytometry and enzyme-linked immunospot (ELISpot) assay. Results: The results demonstrated that the LNP-encapsulated PolyI:C adjuvant significantly increased the secretion of HBsAg-specific IFN-γ, IL-2, and TNF-α by splenocytes, indicating a Th1-biased and cytotoxic T lymphocyte (CTL)-mediated cellular immune response. In addition, this formulation markedly elevated serum titers of HBsAg-specific IgG, IgG1, and IgG2a. Conclusions: These findings underscore the advantages of the LNP-PolyI:C adjuvant in enhancing both humoral and cellular immunity, demonstrating its considerable potential as a novel adjuvant. Full article

Hapten-based immunotherapies represent a promising strategy to enhance the immunogenicity of tumor antigens and promote antitumor immune responses. Chemical conjugation of small haptens to antigens generates novel antigenic determinants that increase immune recognition. Mechanistic studies indicate that haptenation enhances antigen uptake, dendritic cell maturation, and the activation of both cellular and humoral immunity. In preclinical models, hapten-modified antigens induce robust immune activation, tumor regression, and durable immune memory. Clinically, dinitrophenyl-modified autologous tumor cell vaccines elicit delayed-type hypersensitivity responses and clonal T-cell expansion, with evidence of clinical activity and a favorable safety profile. However, their clinical benefit remains to be confirmed in larger, randomized studies. Emerging strategies include in situ haptenation and bihaptenized or stressed hapten-modified allogeneic platforms, which aim to expand epitope diversity and enhance immune priming. Hapten-based immunotherapies offer a clinically feasible approach to converting poorly immunogenic tumors into effective immune targets. Full article

Background/Objectives: Our previous study demonstrated that while the third SARS-CoV-2 booster effectively enhanced immunity against the Delta subvariant, its protection declined over time. This study aimed to evaluate and compare the humoral and cellular immune responses, as well as reactogenicity, of the mRNA-1273 vaccine administered as a fourth booster in healthy Thai adults previously vaccinated with two doses of CoronaVac (CV) followed by a third dose of either AZD1222 (AZ) or BNT162b2 (BNT). Methods: Participants received a single 100 µg (0.5 mL) intramuscular dose of mRNA-1273. Blood samples were collected at baseline (D0), D14, D90, and D180 to assess anti-RBD IgG, conduct a surrogate virus neutralization test (sVNT) against the Delta and Omicron variants, and assess IFN-γ levels and reactogenicity. Results: Both 2CV/AZ- and 2CV/BNT-primed groups exhibited comparable local and systemic reactogenicity. The fourth mRNA-1273 dose markedly increased Delta variant inhibition within 14 days in both groups and remained at high levels at Days 90 and 180. sVNT inhibition against Omicron rose similarly in both groups at Day 14; it declined sharply by Days 90 and 180, with the 2CV/AZ-primed group showing significantly lower levels than the 2CV/BNT-primed group. Baseline anti-RBD IgG levels were lower in the 2CV/AZ group (p = 0.003) but surpassed those of the 2CV/BNT group by Day 14, with no significant differences at later time points. IFN-γ responses followed a similar pattern to anti-RBD IgG Conclusions: A heterologous fourth mRNA-1273 booster in both 2CV/AZ- and 2CV/BNT-primed groups effectively enhances B-cell and T-cell responses against SARS-CoV-2. However, emerging variants such as Omicron may still pose challenges. The trial was registered with the Thai Clinical Trials Registry: the name of the registry: “The comparison of immune response to the 4th dose booster with mRNA-1273 COVID-19 vaccine in individuals who had received 2 doses of CoronaVac and booster with ChAdOx-1 or BNT162b2 COVID-19 vaccine”, TCTR20220205002 on 5 February 2022. Full article

Orf virus (ORFV) is a globally distributed zoonotic parapoxvirus that causes a highly contagious mucocutaneous disease in small ruminants. Despite the urgent demand for vaccination-based control, no licensed vaccines are currently available universally. In this study, we generated two recombinant Sendai virus (SeV) vectors expressing ORFV 011 (rSeV-GFP-B2L) and ORFV 059 (rSeV-GFP-059) genes and evaluated their ability to stimulate antiviral responses in vitro. Following the transduction, we assessed transgene expression, innate immune activation, induction of interferon-stimulated genes (A3Z1, OBST2, SAMHD1), and antiviral activity. Both vectors significantly upregulated pattern recognition receptors (TLRs, RIG-I) and type I interferon (IFN-β) genes, with rSeV-GFP-059 inducing the strongest response. Remarkably, OBST2 was robustly upregulated, suggesting a potential role in restricting ORFV replication. Antiviral activity assays revealed a marked reduction in ORFV DNA copies and a mild decrease in ORFV RNA transcription in rSeV-GFP-059-transduced cells, particularly at later time points, accompanied by complete abrogation of the typical cytopathic effect. Collectively, these results demonstrate that SeV-based vectors, particularly rSeV-GFP-059, efficiently prime antiviral immunity and suppress ORFV replication, establishing a promising platform for further in vivo vaccine evaluation in sheep. Full article

Background/Objectives: Eliciting robust immune responses against the hepatitis B virus (HBV) through therapeutic vaccination holds promise for curing chronic hepatitis B. We previously developed the heterologous protein prime/viral vector boost clinical vaccine candidate, TherVacB. Here, we evaluated a replication-competent chimeric vesicular stomatitis virus vector (VSV-GP) as an alternative viral vector boost vaccine. Methods: A recombinant VSV-GP vector co-expressing HBV surface and core antigens (VSV-GP-HBs/c) was generated and characterized for antigen expression. Its immunogenicity, antiviral efficacy, and durability were assessed in HBV-naïve and HBV-carrier mice, using protein primed, viral vector-primed, and multi-viral vector boost regimens. Results: VSV-GP-HBs/c efficiently expressed both HBV antigens in vitro. A single immunization with VSV-GP-HBs/c induced only weak HBV-specific immune responses in vivo. Replacing protein priming with VSV-GP-HBs/c resulted in modest immune activation and limited antiviral effects in HBV-carrier mice. In contrast, substituting the modified vaccinia virus Ankara (MVA)-HBs/c boost in the TherVacB regimen with VSV-GP-HBs/c elicited robust HBV-specific antibody responses and strong CD4 and CD8 T-cell immunity, assessed by intracellular IFN-γ staining after peptide stimulation. This regimen achieved a substantial reduction in serum HBsAg levels, numbers of HBV-positive hepatocytes, and intrahepatic HBV-DNA, with antiviral efficacy comparable to that of the classical TherVacB regimen. Notably, a second viral vector boost did not enhance HBV-specific immunity or antiviral efficacy; instead, it promoted dominant vector-specific CD8 T-cell responses. Long-term analyses performed 10 weeks after the last vaccination further demonstrated that a single protein-prime/VSV-GP-HBs/c boost was sufficient to achieve sustained antiviral control. Conclusions: These findings identify VSV-GP-HBs/c as an effective boost vector for therapeutic hepatitis B vaccination and establish protein priming followed by a single viral vector boost as an optimal strategy for sustained antiviral immunity. Full article

Managed colonies of the Western honey bee, Apis mellifera, are essential to global food security by ensuring the pollination of a wide array of crops that are crucial for human consumption. However, substantial declines in managed honey bee populations have been reported worldwide, including in Australia, the United States and Europe. These losses have been attributed to the multifaceted interplay of stressors encompassing agrochemical impact, climate fluctuations, pathogens, suboptimal forage conditions, and habitat reduction. In particular, Paenibacillus larvae, the causative agent of American foulbrood (AFB), is one of the most destructive bacterial pathogens for honey bees due to its high transmissibility, environmental persistence, and capacity to cause complete colony collapse. Recurrent and widespread AFB outbreaks impose significant economic and biosecurity burdens on apiarists, exacerbating declines in pollination services and agricultural productivity. This review synthesises the current landscape of therapeutic strategies targeting AFB, including bacteriophage-based approaches, vaccine development, probiotics, and essential oils, and evaluate their reported field applications, efficacy, and practical limitations. Bacteriophages and immune-priming approaches show the greatest potential to reduce larval mortality and pathogen load, although their application is constrained by formulation stability, delivery challenges, and limited large-scale field validation. Probiotics and essential oils produce highly variable and inconsistent effectiveness under field conditions. Overall, these alternatives currently represent promising complementary tools rather than standalone treatments, underscoring the need for further investigation. Full article

Pigeon Newcastle disease poses a persistent threat to the global pigeon industry, underscoring the need for effective vaccination strategies. While both inactivated and DNA vaccines offer distinct advantages, the immunogenicity of a combined heterologous regimen remains underexplored. This study evaluated and compared three immunization strategies in pigeons: a DNA vaccine encoding the NDV F protein fused with chicken IL-18, an inactivated vaccine from a local virulent strain, and a DNA prime-inactivated boost regimen. The preparation workflows for both vaccine platforms are described in detail to provide methodological context for the immunological comparison. Critically, the prime–boost regimen elicited significantly higher hemagglutination inhibition (HI) antibody titers than either vaccine administered alone, demonstrating a clear synergistic effect. These findings highlight the complementary roles of the two platforms and provide a strong immunological rationale for further evaluation of this sequential strategy. Future studies incorporating viral challenge experiments and long-term immune monitoring are needed to determine whether the enhanced HI antibody response translates into protective efficacy under field conditions. Full article