Search Results (582)

Bacterial membrane vesicles (BMVs), encompassing outer membrane vesicles (OMVs) released from Gram-negative bacteria and extracellular vesicles (EVs) released from Gram-positive bacteria, have emerged as promising vaccine platforms owing to their intrinsic immunostimulatory properties and capacity to deliver a wide range of antigens. Although conventional vaccines effectively prevent infectious diseases, their long-term efficacy is often limited by antigenic variation and reliance on a restricted number of licensed adjuvants. BMVs, as self-adjuvanting systems, enable both antigen delivery and innate immune activation. BMVs are nanoscale lipid bilayer structures enriched with pathogen-associated molecular patterns (PAMPs), facilitating their recognition and uptake by antigen-presenting cells. This leads to the activation of pattern recognition receptors and the induction of pro-inflammatory cytokines, type I interferons, and adaptive immune responses, including antibody production and Th1- and Th17-biased cellular immunity. Recent studies highlight the versatility of BMVs as vaccine platforms across bacterial, fungal, and viral infection models. BMVs induce protective immunity by promoting both systemic and mucosal immune responses, thereby reducing bacterial burden and limiting pathogen colonization across diverse infection models. These properties have supported their application in viral vaccine development, including influenza and SARS-CoV-2, with the potential to enhance mucosal immunity. Despite these advantages, challenges remain in standardization, safety, and antigen-loading efficiency. Engineered BMVs incorporating protein or mRNA antigens may further enhance antigen presentation and CD8⁺ T cell responses. This review summarizes the biological features, immunological mechanisms, and future potential of BMVs in vaccine development. Full article

To evaluate the immune-enhancing effects of Polygonatum cyrtonema polysaccharides in vivo, an immunodeficiency zebrafish model was established by microinjecting vinorelbine tartrate into the caudal vein. Effects of the polysaccharides (500, 1000 and 2000 μg/mL) on neutrophil counts were assessed in Tg (mpx:GFP) zebrafish. Transcriptome sequencing was employed to investigate the immunomodulatory effects of the polysaccharides. The results revealed a dose-dependent increase in neutrophil counts following treatment with the polysaccharides. Transcriptomic profiling identified 1286 DEGs across the three comparison groups. GO and KEGG enrichment analyses indicated that the polysaccharides could modulate immune-related pathways in the zebrafish model. Two enriched KEGG pathways, including the MAPK signaling and the mTOR signaling pathway, were utilized to analyze immune-related gene expression. To validate RNA-seq data, qRT-PCR was performed on selected DEGs, including il1b, crk, fgf10b, atp6v1aa, and eif4e1c. The results confirmed that the expression patterns of these genes were consistent with the RNA-seq data. Within the tested concentrations (500, 1000 and 2000 μg/mL), the polysaccharides exhibited a dose-dependent immunostimulatory effect, with the highest immunostimulatory response observed at 2000 μg/mL. The molecular level primarily involves the enhancement of neutrophil function through the modulation of multiple immune-related pathways. These findings provide a theoretical basis for the potential application of Polygonatum cyrtonema polysaccharides as a natural immunomodulatory agent. Full article

Rosa roxburghii Tratt is recognized as an edible and medicinal plant valued for its nutritional and medicinal properties. Polysaccharides are among its key bioactive constituents. A homogeneous polysaccharide, designated RTW-1, was extracted and purified from the fruit of Rosa roxburghii Tratt. Its molecular mass was determined by HPLC to be 2.16 × 10³ kDa. Monosaccharide composition and methylation analysis showed that RTW-1 is mainly composed of glucose, arabinose, and galacturonic acid in a molar ratio of 1.00:0.48:0.74. The uronic acid content was measured as 55.21%, and the degree of esterification was 58.30%. The glycosidic linkages identified included (→2,3,4)-Manp-(1→, →4)-Arap-(1→, →4)-GalAp-(1→, T-Rhap, →4)-Glcp-(1→, and (→2,3,4)-Xylp-(1→). Shear-thinning behavior was revealed by rheological analysis. At 30 mg/mL, the thixotropic loop area reached 143.8 Pa/s, which was 20 times higher than that at 12 mg/mL. In RAW264.7 macrophages, cell proliferation was promoted by RTW-1. At 80 μg/mL, phagocytic activity was increased by 88%, and NO production was enhanced by 3.1-fold. Concentration-dependent upregulation of TNF-α, IL-6, IL-1β, and IL-10 mRNA expression was observed by qRT-PCR, with maximum increases of 3.2-, 4.1-, 2.8-, and 2.5-fold, respectively. In conclusion, RTW-1 possesses favorable gel-forming and immunostimulatory properties and shows potential for promoting intestinal immune activity, suggesting its promise as a functional food ingredient. Full article

The immunomodulatory potential of natural polysaccharides is often limited by their structural complexity and high molecular weight. In this study, DFIP-A3-1 (M_w = 8.68 × 10³ g/mol) was obtained from the leaves of Isatis indigotica Fort. by ultrafiltration, DEAE-650M, and Sephadex G-100 chromatography, followed by acid degradation. Fortunately, DFIP-A3-1 exhibited the most potent immunostimulatory activity in vitro. HPGPC, HPSEC-MALLS-RID, GC-MS, FT-IR, Congo red tests, SEM, and AFM were used to characterize their structure, and 1D/2D NMR was used for further investigation of DFIP-A3-1 for in-depth structural clarification. DFIP-A3-1 was primarily composed of Rha and Gal. Based on methylation and NMR analyses, the structure of DFIP-A3-1 was elucidated as follows: →1)-β-Galp-(4→1,4)-α-Rhap-(2→1,4)-α-Rhap-(2→1)-β-Galp-(6→1)-β-Galp-(6→1,6)-β-Galp-(3→1,6)-β-Galp-(3→. Furthermore, DFIP-A3-1 was found to exhibit a triple-helix conformation. DFIP-A3-1 markedly upregulated the secretion of NO, IL-6, and TNF-α and enhanced the mRNA expression levels of their related genes in RAW 264.7 cells. Moreover, DFIP-A3-1 activated p-IκBα, p-p65, and TLR4, while co-treatment with TAK-242 markedly suppressed the expression of these pathway-related proteins. All of the aforementioned findings suggested that DFIP-A3-1 is a promising natural immunomodulatory drug deserving of additional research and use. Full article

Pasteurella multocida (P. multocida) is a significant pathogenic bacterium that causes serious disease and death in the yaks of the Tibetan Plateau, and the existing inactivated vaccines are limited by low protection and reactogenicity. Outer membrane vesicles (OMVs) derived from a yak-origin serogroup B P. multocida isolate were evaluated as a potential vaccine candidate in the present study. The purified OMVs were characterized by transmission electron microscopy and nanoparticle tracking analysis, which demonstrated the presence of typical bilayer vesicles ranging from 20 to 300 nm in diameter. Proteomic profiling revealed 1213 proteins, with many of them being immunologically relevant outer membrane-associated proteins like OmpA, OmpH, Omp16, OmpW, TbpA and PlpP. The functional enrichment analysis showed that these proteins were linked to translation, membrane structure, transport, metabolism, and pathways of adaptation of bacteria. In vitro OMVs were effectively taken up by RAW264.7 macrophages and stimulated robust expression of inflammatory mediators, such as TNF-α, IL-1β, IL-6, iNOS and IL-10, which is indicative of strong innate immunostimulatory capacity. OMV immunization induced significant antigen specific humoral responses in mice and yaks in vivo. In mice, intramuscular immunization was effective in giving full protection against P. multocida challenge but not intranasal immunization. Histopathology also indicated less tissue damage in vaccinated animals, especially in the lung and liver. These findings, taken together, prove that yak-derived P. multocida OMVs have high immunogenicity and protection capabilities, which show their potential as a next-generation vaccine platform to tackle P. multocida infection. Full article

Differences in the gut microbiota are directly reflected in lung–gut axis crosstalk, which may increase susceptibility to pulmonary infections, such as those caused by the bacterium Pseudomonas aeruginosa. Deficiency of the cytokine IL-10 leads to gut inflammation, and this pro-inflammatory environment is partly due to changes in the gut microbiota. To better understand the effects of IL-10 deficiency on the gut microbiota, the intestinal microbial composition of IL-10 KO mice was assessed, and an increase in the phyla Bacteroidetes and Proteobacteria and a decrease in the phylum Firmicutes were observed in the faeces compared with the wild-type group (WT). Additionally, IL-10 KO mice had a higher pro-inflammatory immunostimulatory caecal content. Furthermore, it was found that heterologous faecal microbiota transplantation (FMT) between groups reversed this gut imbalance. IL-10 KO mice showed greater susceptibility to acute pulmonary infection by P. aeruginosa, with a higher recovery of viable bacteria in the lung and spleen, greater tissue damage and increased expression of genes encoding pro-inflammatory cytokines in the lungs. This greater susceptibility was reversed after FMT. Taken together, these results demonstrate the role of endogenous IL-10 in the gut microbiota constitution and its importance in the pulmonary immune response against P. aeruginosa infection. Full article

The advent of immune checkpoint inhibitors has driven progress in hepatocellular carcinoma (HCC) treatment outcomes and enabled opportunities for combining therapeutic modalities. Growing evidence substantiates the utility of radiotherapy, particularly at ablative doses, in the management of HCC. Given the potential for radiotherapy to induce an immunostimulatory environment and potentiate immune checkpoint inhibitor activity, the expanding HCC treatment landscape compels exploration of the combination of radiotherapy and immunotherapy. This review highlights recent advances in the treatment of HCC using radiotherapy and immunotherapy in combination. Radiation can potentiate an anti-tumor response and tumor microenvironment permissive to immunotherapy. Results from randomized clinical trials and retrospective studies consistently show that combinations of radiotherapy and immunotherapy improved the treatment outcomes of unresectable or advanced HCC—especially HCC with macrovascular invasion. Active research to further improve treatment efficacy and reduce side effects is exemplified by more than 20 ongoing clinical trials combining external beam radiotherapy and immunotherapy to treat HCC. Ongoing research aims at prolonging survival and downstaging advanced or unresectable HCC. Full article

Systemic lupus erythematosus (SLE) is characterized by chronic immune activation, enhanced type I interferon signaling, and epigenetic dysregulation, conditions that may promote the reactivation of human endogenous retroviruses (HERVs). Whether HERV activation in SLE is global or selective, however, remains unclear. We analyzed the expression of HERV-H, HERV-K, and HERV-W, along with the HERV-derived envelope genes Syncytin-1 and Syncytin-2, in samples from lupus patients and healthy controls. In parallel, we assessed the expression of the epigenetic repressors TRIM28 and SETDB1. HERV-H expression was comparable between groups, whereas HERV-K and HERV-W were significantly overexpressed in lupus patients. Syncytin-1 and HERV-W env transcripts were markedly increased in SLE, while Syncytin-2 expression was unchanged. Lupus patients showed reduced TRIM28 and increased SETDB1 expression, consistent with altered regulation of HERV repression pathways. Notably, HERV-H and HERV-W pol expression correlated with the type I interferon score, suggesting an association between interferon signaling and selective HERV activation. These findings indicate that SLE is associated with the selective activation of immunostimulatory HERV families, particularly HERV-W. The observed associations with interferon signaling suggest that HERV-W-related transcripts may represent disease-associated molecular signatures, warranting further mechanistic investigation. Full article

The spherical pectin is an important bioactive component of chrysanthemum tea infusion, but its biological function, primary structure, and structure-activity relationship remain unclear. The present study evaluated the immunostimulatory activity of spherical pectin from Chrysanthemummorifolium Ramat. ‘Hangbaiju’ tea infusion in RAW264.7 cells and preliminarily investigated its structure-immunostimulatory activity relationship. The rhamnogalacturonan-I (RG-I) domain played a key role in the immunostimulatory activity of spherical pectin. Terminal and branched arabinose residues together accounted for 73.8% of the total arabinose residues in spherical pectin, indicating that the arabinan chains of spherical pectin were highly branched. The backbone of these arabinan chains consisted of →5)-α-Araf-(1→ repeats, and additional →5)-α-Araf-(1→ branches were linked to the backbone via α-1,3-glycosidic linkages. The spherical pectin rich in highly branched arabinan chains activated RAW264.7 cells via recognition by toll-like receptor 4 (TLR4). Molecular docking analysis revealed that →5)-α-Araf-(1→ branches in spherical pectin could bind to toll-like receptor 4/myeloid differentiation protein-2 (TLR4/MD-2) complexes and stabilize the dimer structure, which represents an important mechanism for its immunostimulatory activity. This study provides new insights into the structure-function relationship of spherical pectin. Full article

Periodontitis is a multifactorial inflammatory disease characterized by dysbiotic microbial communities and progressive destruction of the supporting periodontal tissues, ultimately leading to alveolar bone loss. Achieving predictable periodontal regeneration remains a major clinical challenge because of the complex interplay between inflammation, microbial burden, and tissue remodeling. In this context, hyaluronic acid (HA), a naturally occurring component of the extracellular matrix (ECM), has gained increasing attention as a bioactive adjunct in periodontal therapy. This narrative review aims to describe current evidence regarding the biological properties, molecular mechanisms, and clinical applications of HA in periodontal therapy, with a particular focus on its immunomodulatory, antimicrobial, and regenerative potential. Available data indicate that HA exerts molecular weight–dependent effects, ranging from anti-inflammatory and extracellular matrix–stabilizing actions to osteogenic and immunostimulatory responses. Clinically, HA has been investigated as an adjunct in both nonsurgical and surgical periodontal therapies, as well as in minimally invasive regenerative approaches, as it has favorable effects on inflammation control, soft tissue healing, and clinical attachment gain. Recent advances in materials science have further expanded the role of HA through the development of engineered hydrogels and hybrid delivery systems incorporating nanoparticles, bioactive glass, growth factors, or antimicrobial agents, which have demonstrated promising osteogenic and antibacterial outcomes in preclinical models. However, the interpretation of existing evidence is limited by heterogeneity in HA formulations, short follow-up periods, and inconsistent reporting of periodontal defect morphology. Future research should focus on standardized, well-designed preclinical and clinical studies integrating histological, radiographic, immunological, and microbiological assessments to distinguish true periodontal regeneration from repair and to optimize HA-based strategies tailored to specific defect configurations. Full article

Background: Immunomodulatory compounds can modify or regulate the immune responses. Given that vaccine-induced immune responses can vary in magnitude and durability depending on antigen properties and adjuvant selection. Immunomodulators that enhance antigen-specific immune responses with low toxicity may complement existing adjuvant systems. Recent studies indicate that adenosine receptor–mediated signaling can modulate dendritic cell (DC) function through mechanisms distinct from classical pathogen-associated molecular pattern (PAMP)-driven Toll-like receptor pathways. Methods: In this context, the present study comparatively evaluates poly-(lactic-co-glycolic acid) (PLGA) microparticle–encapsulated β-L-adenosine (BLA MPs) alongside established FDA-approved adjuvants to assess their immunomodulatory potential under limited-antigen conditions. FDA-approved PLGA was used to encapsulate BLA in combination with multiple viral antigens, including H1N1 influenza, Zika virus, and canine coronavirus, to enable sustained delivery, antigen protection, and efficient uptake by antigen-presenting cells. Results: Physicochemical characterization demonstrated uniform particle size distribution, a low polydispersity index, and a stable negative surface charge. Release studies showed more than 50% payload release within 12 h, with release kinetics best described by the Korsmeyer–Peppas model. Cytotoxicity evaluation using DC2.4 cells confirmed that BLA MPs were non-cytotoxic at concentrations up to 250 μg/mL. Comparative in vitro immunological assessments revealed that BLA MPs induced dendritic cell activation, including upregulation of antigen-presenting and co-stimulatory molecules, at levels largely comparable to those observed with Alum- and MF59-based formulations across multiple antigen groups. Nitric oxide production remained within comparable ranges, indicating balanced immunostimulatory activity without excessive inflammatory signaling. In select conditions, co-formulation of BLA MPs with MF59 further enhanced DC activation, supporting its role as a complementary immunomodulatory component. Conclusion: These findings align with previously reported adenosine-dependent pathways involved in DC maturation and antigen presentation. Overall, this comparative study demonstrates that PLGA-encapsulated β-L-adenosine functions as an effective immunomodulatory agent, with performance comparable to that of established FDA-approved adjuvants across diverse vaccine antigens. Further in vivo studies are warranted to evaluate dose dependency, cytokine profiles, and antibody responses to define its role within combinatorial vaccine adjuvant strategies. Full article

Background/Objectives: Tuberculosis (TB) remains a major global health challenge, and the Bacillus Calmette–Guérin (BCG) vaccine has limited efficacy against adult pulmonary disease. Protein subunit vaccines are a promising alternative but require strong adjuvants to induce cell-mediated immunity. Synthetic agonists targeting toll-like receptor 4 (TLR4) and stimulators of interferon genes (STINGs) have emerged as effective immunostimulants. Therefore, we aimed to evaluate the immunogenicity and protective efficacy of Ag85B-based subunit vaccines formulated with synthetic TLR4 and STING agonists in a BCG-boosted mouse model. Methods: Three synthetic adjuvants—QTP709-1, QTP709-3, and QTP701—were formulated as oil-in-water emulsions containing distinct surfactant and immunostimulant components. The potential of vaccine formulations to activate dendritic cells (DCs) and elicit Ag85B-specific immune responses, including IgG subclass levels, interferon-γ (IFN-γ) enzyme-linked immunosorbent spots, and polyfunctional T-cell responses, was assessed by flow cytometry. Protective efficacy was evaluated based on pulmonary bacterial burden and histopathology following Mycobacterium tuberculosis (M. tb) Erdman challenge. Results: All formulations promoted DC maturation and enhanced antigen-specific immune responses. Each adjuvant elicited strong Ag85B-specific humoral immunity, increased IFN-γ secretion, and polyfunctional CD4⁺ and CD8⁺ T cells co-producing IFN-γ, TNF-α, and interleukin-2. Among them, QTP709-1 was associated with increased levels of chemokine receptor 5-associated chemokines and showed a trend toward reduced lung bacterial burden and histopathological inflammation following M. tb challenge. Conclusions: Synthetic TLR4 and STING agonists were associated with enhanced immunogenicity of TB subunit vaccines and showed evidence of protective potential, with TLR4-based formulations exhibiting more pronounced immunological responses. QTP709-1 exhibited strong immunostimulatory and protective effects, supporting its potential as a candidate adjuvant for next-generation TB vaccines. Full article

Cancer immunotherapy has transformed modern oncology, yet durable responses remain limited for many patients due to immune exclusion, adaptive resistance, and tumor heterogeneity. Oncolytic viruses (OVs) have emerged as a novel class of immunotherapeutics that unify direct tumor cytolysis with stimulation of antitumor immunity. By inducing immunogenic cell death (ICD) and releasing tumor-associated antigens (TAAs), OVs remodel the tumor microenvironment (TME) into an inflamed and immune-permissive niche capable of enabling systemic immune activation. Rapid advances in viral engineering have strengthened the translational potential of OVs through tumor-selective gene deletions, tumor-specific promoters, microRNA-based detargeting, and receptor-retargeting strategies that collectively enhance safety, specificity, and intratumoral propagation. Next-generation OVs are increasingly “armed” with immunostimulatory payloads—including cytokines, chemokines, checkpoint inhibitors, bispecific T-cell engagers, and suicide gene systems—allowing localized immune modulation with reduced systemic toxicity. These innovations have propelled significant clinical progress, exemplified by the approvals of talimogene laherparepvec (T-VEC), G47Δ, and H101, and have driven a surge of combination trials integrating OVs with immune checkpoint blockade, adoptive cell therapies, radiotherapy, and targeted therapies to overcome multilayered tumor immune resistance. Despite this momentum, clinical implementation remains challenged by antiviral immunity, heterogeneous viral distribution, stromal barriers, and dynamic interferon (IFN) signaling in the TME. Emerging delivery approaches, including carrier cell systems, nanotechnology-enabled viral shielding, and synthetic virology platforms, offer promising solutions to these limitations. Oncolytic virotherapy is rapidly evolving into a multifunctional immunotherapeutic platform capable of reshaping antitumor responses at both local and systemic levels. By integrating advanced viral engineering with rational combination strategies and innovative delivery technologies, OVs hold substantial potential to overcome current barriers in cancer immunotherapy and advance precision oncology. Continued translational research will be essential to fully harness their therapeutic impact and broaden their clinical applicability. Full article

Background/Objectives: We performed a systematic review of preclinical literature on the use of high-LET particle therapy, DDRi, and/or immunotherapy specifically in pMMR colorectal cancer. Methods: A systematic review of the literature published between 2014 and 2025 was conducted across major databases. Studies were included if they examined particle radiotherapy (e.g., proton, alpha, and carbon) or X-ray radiation either alone or in combination with DDRi and/or immune checkpoint inhibitors (ICIs) in pMMR colorectal cancer models. Results: In total, 131 studies met the inclusion criteria, including 70 preclinical studies. These studies consistently demonstrate that high-LET radiation amplifies immunogenic cell death, increases cGAS-STING pathway activation, and enhances tumor antigen presentation, thereby fostering greater immune infiltration and systemic antitumor responses. Concurrent irradiation with DDRi enhances persistent DNA damage and cytosolic DNA accumulation. In murine models, high-LET therapies show excellent local control, with manageable toxicity profiles. Combination regimens with ICIs exhibit improved local control and elicit systemic antitumor immune responses. Conclusions: High-LET particle radiation and/or the use of concurrent DDRi with ICI have significant preclinical evidence of immunostimulatory effects in pMMR rectal adenocarcinoma and increased response rates to immunotherapy. The clinical evidence will be reviewed in the companion manuscript. Full article

Background/Objectives: We performed a systematic review of the current clinical and preclinical literature on the use of particle therapy, DDRi, and/or immunotherapy, specifically for pMMR colorectal cancer. Methods: A systematic review of the literature published between 2014 and 2025 was conducted across major databases. Studies were included if they examined particle radiotherapy (e.g., proton, alpha, carbon) either alone or in combination with DDRi and/or immune checkpoint inhibitors (ICI), or X-ray radiotherapy (XRT) in combination with DDRi/ICI. Results: In total, 133 studies met the inclusion criteria, including 62 clinical studies. Clinically, particle therapies show excellent local control and normal tissue sparing, with manageable toxicity profiles. Trials with any form of radiation and DDRi are few, potentially owing to toxicity concerns. ICI combinations showed promising efficacy with XRT, with no randomized trials comparing them to particle radiation. Conclusions: Particle radiation and/or DDRi have significant preclinical evidence of immunostimulatory effects in pMMR rectal adenocarcinoma and increase response rates to immunotherapy (presented in the companion manuscript). Despite strong preclinical evidence and rationale, clinical trials including all three modalities are scarce. Existing evidence suggests a potential benefit based on extrapolation from photon-based studies and supports prospective evaluation with careful attention to treatment-related toxicity, which remains a concern. Full article