Frontiers in Immunology最新文献

Background: The Plasmodium falciparum Rh5-interacting protein (PfRipr) is a key component of the pentameric PTRAMP-CSS-PfRipr-CyRPA-RH5 (PCRCR) complex, which is essential for erythrocyte invasion. Antibodies against PfRipr can inhibit parasite growth, but the full-length protein is structurally complex and challenging to produce as a recombinant antigen. We previously found that a specific PfRipr fragment, PfRipr5, was the most potent antigen; however, identifying minimal functional regions within PfRipr5 is critical for improving the vaccine design.

Methods: We investigated PfRipr5, a truncated fragment of PfRipr consisting of EGF-like domains 5-9, and identified the epitope recognized by the growth-inhibitory monoclonal antibody 29B11. Epitope characterization was conducted using Western blotting with cysteine-substituted mutants and surface plasmon resonance (SPR) analysis with a single-site kinetics model.

Results and conclusion: The identified 20-amino-acid region represents a cysteine-associated epitope recognized by the growth-inhibitory monoclonal antibody 29B11. This study defines a growth-inhibitory epitope within PfRipr5 whose recognition is associated with cysteine integrity. These findings provide a tractable molecular entry point for dissecting PfRipr function and support epitope-focused strategies for rational design of subunit vaccines against blood-stage malaria.

Background: Breast cancer is one of the most prevalent malignancies and a leading cause of cancer-related mortality among women. Lactylation, a recently recognized post-translational modification, has emerged as a significant factor in tumor biology, with increasing evidence linking it to cancer progression and immune modulation. However, the role of lactylation in tumorigenesis remains ambiguous. This raises questions about whether it serves as a primary driver or a secondary regulator during cancer development, as well as its influence on the tumor immune microenvironment and prognostic implications.

Methods: This study investigates the clinical relevance of lactylation-related genes (LRGs) in breast cancer through a comprehensive analysis of extensive genomic datasets, including single-cell RNA sequencing, bulk transcriptomic data, and spatial transcriptomics from established public databases such as TISCH, TCGA, and GEO.

Results: By using a combination of multiple machine-learning algorithms, we developed an effective lactylation-related signature that correlates with immune cell infiltration, chemokine expression, and tumor mutation burden. This signature proved useful in identifying breast cancer patients likely to respond to immunotherapy. Finally, we experimentally validated the quantified expression levels of hub genes in human breast samples and demonstrated the role of SUSD3.

Conclusion: These findings indicate that our lactylation risk model can be used to predict the malignant progression and immune evasion of breast cancer. It is expected to become a potential therapeutic target and a diagnostic marker for breast cancer. This model also provides insights into breast cancer therapy and an effective framework for developing gene screening models applicable to other diseases and pathogenic mechanisms.

Background: Cyclosporine A (CsA)-induced nephrotoxicity is a significant cause of chronic kidney disease (CKD), primarily driven by aberrant activation of the NF-κB and TGF-β1 signaling axes. Vericiguat, a soluble guanylate cyclase (sGC) stimulator, has established cardioprotective effects, but its potential renoprotective role and underlying mechanisms in CsA-induced CKD remain unexplored.

Methods: An integrative approach was employed. Network pharmacology identified common targets between vericiguat and CKD. Mendelian randomization (MR) analysis assessed the causal relationship between drug target genes and CKD risk. The therapeutic effects and mechanisms of vericiguat were subsequently validated in vivo using a CsA-induced mouse model and in vitro in human renal tubular epithelial (HK-2) cells.

Results: Integrated computational analyses pinpointed the NF-κB/TGF-β1 axis as a core target of vericiguat. In mice, vericiguat treatment dose-dependently ameliorated CsA-induced renal dysfunction, proteinuria, renal inflammation, oxidative stress, and fibrosis. In HK-2 cells, vericiguat suppressed CsA-triggered inflammatory cytokine secretion, fibrotic marker expression, and reactive oxygen species production. Mechanistically, vericiguat inhibited the phosphorylation of the IKKβ/IκBα/NF-κB p65 pathway and the activation of TGF-β1/Smad signaling, thereby disrupting the inflammation-fibrosis vicious cycle. Genetic manipulation confirmed p65 as a crucial nodal point in this regulatory network.

Conclusion: This study demonstrates that vericiguat exerts renoprotective, anti-inflammatory, and anti-fibrotic effects in CsA-induced CKD by modulating the NF-κB/TGF-β1 axis. These findings provide a novel scientific rationale for drug repurposing of vericiguat and highlight its potential therapeutic value for CKD.

Background: The differentiation of naïve CD8⁺ T cells into effector cells upon activation is essential for eliminating intracellular pathogens and cancerous cells, although the underlying epigenetic mechanisms remain incompletely characterized.

Methods: Peripheral blood mononuclear cells (PBMCs) were obtained from healthy donors. naïve CD8⁺ T cells were purified and activated with α-CD3/CD28-conjugated microbeads for 0, 24, or 72 h in vitro. Flow cytometry was used to assess cytokine production and activation markers at each time point. Assay for transposase-accessible chromatin using sequencing (ATAC-seq) was performed to identify differentially accessible chromatin regions (DARs). RNA sequencing (RNA-seq) was performed to measure gene expression. Data from ATAC-seq and RNA-seq were integrated to examine the relationship between chromatin accessibility and gene expression. Enriched pathways for DARs and differentially expressed genes (DEGs) were determined by KEGG pathway and gene ontology (GO) enrichment analysis, and transcription factor (TF) binding patterns around these genes were visualized by footprint analysis.

Results: Upon activation, naïve CD8⁺ T cells showed increased production of IFN-γ, TNF, and IL-2, and elevated expression of CD69 and CD95. Integrated ATAC-seq and RNA-seq analysis identified 568 and 541 dual-upregulated genes (showing both increased chromatin accessibility and expression) at 24 and 72 h post-activation, respectively. These early-response genes were enriched in pathways including pyruvate metabolism and the DNA damage response. Footprint analysis predicted the ETS and bZIP TF families as key regulators driving this coordinated chromatin and transcriptional reprogramming. Furthermore, distinct chromatin remodeling patterns were observed in gene sets associated with memory, effector function, exhaustion, and metabolism, revealing that accessibility changes did not always directly correlate with transcriptional outcomes.

Conclusion: This study defines a core set of genes and TFs that critically regulate the initial activation of human naïve CD8⁺ T cells. These results provide a molecular roadmap for future efforts to engineer more potent and durable CD8⁺ T cell responses for adoptive cell therapy.

Background: The pathogenic role of inflammatory cytokine levels in children with septic shock has not been completely clarified. The aim of this study was to investigate the relationships between the early concentrations of inflammatory cytokines, pathogen classification, and 28-day mortality in children with septic shock.

Method: We retrospectively analyzed the early expression of cytokines in children admitted to the pediatric intensive care unit (PICU) of a tertiary pediatric hospital due to septic shock between July 2019 and September 2024.

Results: A total of 189 children with septic shock were included and 68 died within 28 days of hospitalization. The plasma levels of IL-6 (P = 0.001), IL-10 (P < 0.001), IFN-γ (P = 0.002), and TNF-α (P = 0.014) were significantly higher in the nonsurvivor group than in the survivor group. Multivariate Cox regression analysis revealed that the IL-6 level was an independent risk factor for 28-day mortality after controlling platelet count and lactate, lactate dehydrogenase, Hb, IFN-γ, and TNF-α levels. ROC analysis revealed the AUC values of the IL-6, IL-10, IFN-γ, and TNF-α levels were 0.64, 0.68, 0.64 and 0.61, respectively, and that the optimal cutoff values were 414.92 pg/ml, 29.66 pg/ml, 1.605 pg/ml and 0.725 pg/ml, respectively. According to these cutoff values, the survival curves of the groups with high levels of IL-6, IL-10, IFN-γ, and TNF-α differed significantly from those with low levels (p < 0.001, p < 0.001, p = 0.001, and p = 0.001, respectively). In children with positive fluid cultures, there was no statistically significant difference in cytokines levels between the gram-positive bacterial (G+) and gram-negative bacterial (G-) infection groups. However, in children with positive blood cultures, the levels of IL-6 (p = 0.005) and IL-10 (p = 0.003) were significantly higher in the G- group than in the G+ group.

Conclusion: Elevated IL-6 and IL-10 levels are valuable for predicting 28-day mortality and identifying gram-negative bacteremia in pediatric patients with septic shock. IFN-γ and TNF-α levels also have significant value for predicting 28-day mortality. Moreover, the IL-6 level was an independent risk factor for 28-day mortality.

Type I interferons (IFN-I) are multifunctional cytokines with well-established antiviral and antitumor activities. In viral infections and cancer, IFN-I are largely protective, acting through both direct mechanisms, such as induction of antiviral or antiproliferative programs, and indirect mechanisms, mediated through the activation of immune effector cells. During bacterial infections, IFN-I primarily act indirectly, making their role more complex and contradictory. Depending on the context, IFN-I may promote host protection or contribute to pathology, and factors determining these divergent outcomes remain poorly understood. Comparative analysis of existing studies indicates that discrepancies in IFN-I effects arise from multiple pathogen- and host-dependent factors, including pathogen biology, the route of pathogen delivery, infection stage, host immune competence, the magnitude of IFN-I response and other parameters. Among them, the ability of IFN-I to reprogram myeloid cell responses appears to be a critical but insufficiently characterized determinant. This review synthesizes current evidence on IFN-I responses in bacterial infections, with particular emphasis on their effects in the myeloid cell compartment. These include IFN-I ability to inhibit macrophage activation, alter macrophage metabolism, induce myeloid cell death, affect macrophage and neutrophil recruitment, and modulate myeloid cell generation by supporting emergency hematopoiesis and redirecting lineage output toward monocyte or granulocyte generation. Given that macrophages and neutrophils differentially contribute to protection or pathology across various bacterial infections, such effects may underlie both beneficial and detrimental outcomes of IFN-I signaling. The review highlights IFN-I-driven regulation of myeloid cell activity and myelopoiesis as overlooked checkpoints in bacterial pathogenesis, providing a framework for future mechanistic studies and guiding the search for new opportunities in therapeutic intervention.

The enteric nervous system (ENS), a distinctive and intricate compartment of the peripheral nervous system (PNS), is characterized by its capacity to autonomously coordinate fundamental gut functions independent of central nervous system (CNS) input. Comprising vast, densely packed networks of neurons and glial cells distributed throughout the intestinal wall, the ENS not only directly governs motility, secretion, and absorption but also engages in dynamic crosstalk with intestinal immune cells to establish immune defense barriers and fine-tune inflammatory responses. This system is persistently exposed to and deeply engaged with a dynamic microenvironment shaped by both external (e.g., microbiota and their metabolites) and internal (e.g., immune cells, stromal cells) signals. The gut microbiota and its metabolic products play pivotal roles in maintaining mucosal barrier integrity and orchestrating the progression of intestinal inflammation. They influence the development and repair of enteric neurons and can directly participate in disease pathogenesis or exert their effects through immune-mediated mechanisms. This review delves into the complex interplay between the ENS and the gut microbiota within the context of intestinal inflammation pathogenesis.

Background: Mosquito salivary proteins play a crucial role in blood meal acquisition and are known to disrupt host immune responses and homeostasis. Previous studies have identified salivary gland extract from the prominent arbovirus vector, Aedes aegypti, that contains pharmacologically active proteins which can induce cell death in splenic lymphocyte populations in mice. However, it has remained unclear until now whether this effect is unique to A. aegypti or conserved across other Aedes species.

Methods: Here, we characterize the immunomodulatory properties of the salivary gland extracts from Aedes triseriatus, the primary vector of La Crosse virus (LACV). Murine, guinea pig, and human lymphocytes were exposed to salivary gland extracts at varying concentrations and time points. Lymphocyte proliferation was evaluated using colorimetric metabolic assays and flow cytometry analysis to characterize apoptotic mechanisms and define affected lymphocyte subsets.

Results: We found that Ae. triseriatus salivary gland extract inhibited splenocyte proliferation in both mice and guinea pigs through the induction of apoptosis and suppression of cytokine expression. We identified a strong dose-dependent apoptotic phenotype present in CD4⁺, CD8⁺, and CD19⁺ lymphocytes. However, primary human lymphocytes and human lymphoid cell lines did not exhibit reduced proliferation after exposure to salivary gland extracts.

Conclusion: Together, these discoveries suggest that Aedes species saliva contains evolutionarily adapted immunomodulatory proteins that could help facilitate arboviral persistence in rodent reservoirs.

Spectral flow cytometry has ushered in a new era in immunology. Through the improvement of the resolution of surface and intracellular protein expression, this approach enables in depth characterization of rare immune cell subsets, such as innate lymphoid cells (ILCs), in health and disease. Due to their heterogeneity, the identification of ILCs requires the use of many lineage marker antibodies for non-ILC exclusion, together with the analysis of several transcription factor expression profiles for ILC subset distinction. Such intricacies toward their identification and their scarcity in tissues have been key factors directly limiting their characterization, particularly during tumor development and progression. We developed, optimized and validated a 25-parameter spectral flow cytometric panel for the identification of mouse ILC subsets and characterization of their phenotype and proliferation capabilities in mouse mammary tumors. The use of conjugated antibodies coupled to different fluorochromes for the analysis of lineage marker expression further allows the identification and characterization of γδ T cells, CD4⁺ and CD8⁺ αβ T cells, as well as CD19⁺ B cells. Furthermore, we built a bioinformatics pipeline for unbiased immune cell clustering and marker expression analysis. We assessed this panel and downstream bioinformatics analyses on two spectral flow cytometers and found no difference in immune cell identification and clustering save for slight variations in marker intensity, inherent to the specificities of the instrument. These findings highlight the robustness of our developed approach for the identification of innate lymphoid cells in tumors, a method that can be easily implemented for day-to-day analysis of ILCs and other rare immune cell subsets.

Bacterial outer membrane vesicles (OMVs) are nano-sized, lipid-bilayer vesicles naturally released by Gram-negative bacteria. These vesicles are enriched with diverse biomolecules, including lipids, proteins, and nucleic acids, enabling them to mediate critical biological processes. Emerging evidence highlights their pivotal roles in bacterial physiology, intercellular communication, and environmental adaptation, alongside their promising therapeutic potential. This review focuses on recent advances in OMV biogenesis, composition, function and applications. By integrating current knowledge, we aim to inspire novel insights into the molecular mechanisms underlying OMV functions and facilitate their translational development in medicine. Ultimately, this work serves as a comprehensive reference to accelerate future research and clinical utilization of this versatile platform.