Background: Outer membrane vesicles (OMVs) from Gram-negative bacteria are dynamic nanoparticles that shape host–pathogen interactions, acting as both immunostimulatory and immunosuppressive agents critical for microbial pathogenesis and therapeutic innovation. Objective: This scoping review aimed to synthesize recent advancements (2020–2025) in understanding OMVs’ roles in immune modulation, pathogenesis, and microbiota-immune crosstalk, as well as their potential as vaccine platforms and drug delivery systems. Methods: Relevant literature was identified through searches in PubMed, Google Scholar, and Web of Science, targeting peer-reviewed studies from 2020 to 2025. Approximately 80 were selected based on their relevance to OMV biogenesis, immune interactions, and applications in infectious diseases and cancer. Results: OMVs activate proinflammatory pathways via pathogen-associated molecular patterns, contributing to diseases like inflammatory bowel disease and sepsis, while commensal OMVs (e.g., from Bacteroides fragilis) promote tolerogenic immunity and gut homeostasis. Diverse uptake mechanisms enable targeted delivery of virulence or regulatory factors. OMVs enhance microbiota-immune crosstalk, strengthening epithelial barriers and modulating immunity. Therapeutically, bioengineered OMVs show promise in vaccines and personalized medicine, though scalability, heterogeneity, and toxicity pose challenges. Conclusion: OMVs are versatile tools bridging microbiology and immunology, with significant therapeutic potential. This review’s novelty lies in its exclusive focus on Gram-negative OMVs, integrating 2020–2025 advances to address gaps in microbiota-driven immunity and bioengineered therapeutics, guiding future research in vaccine development and clinical translation.

Background/objective: CD40 ligand (CD40L/CD154), a member of the TNF superfamily, plays a critical role in immune regulation. Primarily expressed on CD4⁺ T cells, the CD40-CD40L interaction is essential for B-cell activation, antibody production, and isotype class switching. CD40L expression on T cells has been linked to Mycobacterium tuberculosis (MTB)-stimulated IFN-γ production by peripheral blood mononuclear cells. This study aimed to determine the serum concentration of soluble CD40L (sCD40L) and its surface expression on CD4⁺ T cells in newly diagnosed tuberculosis (TB) patients and in TB patients undergoing anti-tuberculosis treatment (ATT) for 2–3 months. Materials and methods: Ninety-two subjects infected with MTB were recruited and divided into two groups; Group I consisted of 46 newly diagnosed TB patients without prior treatment, and Group II included 46 TB patients receiving ATT for the last 2–3 months. Serum sCD40L concentration of each participant was measured using ELISA, while its surface expression on CD4⁺ T cells was analyzed via flow cytometry. Results: Serum sCD40L levels were significantly lower in (Group I) newly diagnosed TB patients (median = 11.1 ng/mL, IQR = 1.19–20.8) compared to (Group II) patients undergoing ATT (median = 17.4 ng/mL, IQR = 8.9–27.8), with a statistically significant difference between the groups (p = 0.000). The surface expression of CD40L on CD4⁺ T cells was also lower in Group I (median = 2.9, IQR = 0.16–13.99) compared to Group II (median = 3.22, IQR = 0.01–12), though the difference was not statistically significant (p = 0.893). Conclusion: Newly diagnosed TB patients exhibited reduced levels of sCD40L, which increased following 2–3 months of anti-tuberculosis treatment. These findings suggest that CD40L may play a role in the immune response to tuberculosis and that its levels are modulated by treatment.

This editorial note presents the 2025 annual report of AIMS Allergy and Immunology published by AIMS Press. Following a concise overview of the journal’s development in 2025, we propose prospective directions for its advancement in 2026.

Lactic acid bacteria and polyphenols are known to have various health-promoting effects. Pediococcus sp. KB1 (KB1) is a probiotic that was isolated from pickled suguki turnips and has been shown to have potential immunomodulatory activity and strong resistance to gastric acid. Rosmarinic acid (RA) is a phenolic compound commonly found in Lamiaceae plant species, known for its broad anti-inflammatory properties. However, the underlying mechanisms of the combined effects of KB1 and RA on pollinosis remain unclear. The aim of this study was to investigate the effects of oral administration of KB1 and RA on symptom amelioration and anti-inflammatory activity using a murine model of pollinosis. Our results showed that the KB1 + RA group had attenuated sneezing and nasal rubbing in our murine model of cedar pollinosis. The KB1 + RA group exhibited decreased serum histamine levels and reduced Cry j1-specific IgE levels. In both the KB1 and KB1 + RA groups, spleen tissue weight was significantly reduced. In addition, in the KB1 + RA group, increased mRNA expression levels of IL-10, IL-27, IFN-γ, and Foxp3 in the spleen, along with reduced FcεRI-α protein expression, were found. These observations suggest that the combined administration of KB1 + RA may alleviate symptoms by regulating the Th1/Th2 balance and anti-inflammatory cytokines. These results suggest that KB1 and RA may serve as potential natural anti-inflammatory agents for the management of pollinosis.