Search Results (251)

Background: The efficacy of chemotherapy in triple-negative breast cancer (TNBC) is limited by intrinsic resistance and the tumor microenvironment (TME). Accumulating evidence reveals a mechanistic connection between programmed death-ligand 1 (PD-L1) and c-x-c motif chemokine receptor 4 (CXCR4), which dominate stroma barriers, immune escape, and cancer metastasis. Earlier studies have shown that dual suppression of c-x-c motif ligand 12 (CXCL12)/CXCR4 and programmed cell death-1 (PD-1)/PD-L1 pathways regulates extracellular matrix (ECM) deposition, activation of cancer-associated fibroblasts (CAFs), and epithelial–mesenchymal transition (EMT) of pancreatic cancer cells. Methods: We combined BsNb PX4, a bispecific nanobody targeting PD-L1 and CXCR4, with paclitaxel or gemcitabine in multiple tumor cell lines and human peripheral blood mononuclear cell (hPBMC)-reconstituted xenograft mouse models. Antitumor activity was assessed by CCK-8, flow cytometry, and ELISA, and immune cell infiltration and TME remodeling were examined by immunofluorescence, immunohistochemistry, cytokine assays, and RNA-seq. Results: In MDA-MB-231 cells, BsNb PX4 synergistically enhanced paclitaxel-induced growth inhibition and apoptosis via G₂/M cycle arrest. This combinatorial strategy profoundly remodeled tumor immunity by expanding CD8⁺ T cells and depleting Foxp3⁺ CD4⁺ regulatory T cells (Tregs), while concurrently restoring T-cell cytotoxicity and skewing the cytokine balance toward an antitumor state, with elevated IFN-γ and reduced TGF-β1. Notably, compared with paclitaxel monotherapy, the combination significantly elevated intratumoral CD8⁺ T-cell infiltration, decreased Treg abundance, and exerted robust inhibitory effects on tumor growth and metastasis in humanized TNBC xenografts. Conclusions: These findings reveal that dual blockade of PD-L1 and CXCR4 acts synergistically with chemotherapy by triggering tumor cell apoptotic effects and reversing the immunosuppressive microenvironment, thereby emerging as a promising therapeutic strategy for TNBC. Full article

Human secreted phospholipase A₂ group IIA (hGIIA) is a Ca²⁺-dependent extracellular enzyme that supports host defense and amplifies inflammation through lipid mediator generation and receptor-linked signaling. In prostate cancer (PCa), hGIIA is commonly elevated compared with benign tissue and can persist after androgen deprivation, implicating it in tumor progression. PCa is typically an immunologically “cold” disease sustained by an immunosuppressive tumor microenvironment enriched in regulatory T cells ( T_reg), myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), and pro-tumor stromal cells, alongside hypoxia and metabolic rewiring. Because hGIIA is released by innate immune cells and is inducible in macrophages, it is well positioned to strengthen inflammatory lipid networks and promote immune dysfunction within the prostate tumor microenvironment. Here, we review the PCa microenvironment and evaluate evidence linking hGIIA to tumor–stroma crosstalk, angiogenic programming, and therapy resistance, highlighting major knowledge gaps in prostate-focused immune studies. Full article

Thioredoxin peroxidase (TPx) derived from Taenia solium cysticerci (Cysticercus cellulosae) mediates immune evasion by disrupting T cell subset homeostasis. However, its effect on regulatory B cells (Bregs) and the underlying mechanism remain unknown. We stimulated GM12878 B cells with TPx and assessed Breg differentiation by flow cytometry, ELISA, and RT-qPCR. We evaluated the function of TPx-pretreated B cells in co-culture with T cells. We then combined RNA sequencing, Western blot, ELISA, and pharmacological inhibition to identify the signaling pathway involved. TPx increased the CD19⁺CD24^hiCD27⁺ Breg subset in a time-dependent manner, peaking at 72 h. This effect was accompanied by enhanced IL-10 secretion and upregulated transcription of IL-10, TGF-β, and IL-35. TPx-pretreated B cells reduced CD4⁺ T-cell blastogenesis (cell size) and the CD4⁺ fraction of the co-culture and increased the frequency of cells with a CD4⁺CD25⁺CD127⁻ Treg-like surface phenotype. RNA sequencing identified cAMP-related pathways as central to this process. TPx elevated intracellular cAMP and activated the PKA/CREB phosphorylation cascade, whereas the adenylyl cyclase inhibitor SQ22536 reversed TPx-induced Breg differentiation and IL-10 secretion. In this human B cell line model, TPx promotes acquisition of a Breg-like phenotype in an adenylyl cyclase–dependent manner, revealing a novel mechanism of cysticercosis-associated immune evasion. Full article

Background: Type 1 diabetes (T1D) is a complex autoimmune disease demonstrating substantial heterogeneity in age of onset, residual C-peptide levels, clinical outcomes, and therapeutic response. Although the autoimmune classification of T1D has traditionally relied on detection of autoantibodies indicating B-cell involvement, studies targeting total CD3⁺ T cells have underscored the importance of T-cell regulation. Th40 cells, a pathogenic subset of CD3⁺ T cells, first identified in NOD mice, become significantly increased during diabetogenesis. Human subjects with T1D exhibit variable but significantly elevated Th40 levels in peripheral blood. Methods: To target pathogenic effector Th40 cells, we developed OPT101, a 15-mer peptide, and found that it interacts with CD40 in association with an activated integrin, identifying a novel inflammatory receptor complex. We conducted a phase 1b, double-blind, first-in-human clinical trial to evaluate OPT101 and met the primary objectives of safety and tolerability. Results: OPT101 generated only Grade 1 and 2 adverse events. Across eight doses, administered over six weeks, no product-related immune suppression was observed. Secondary objectives included immunologic outcomes and potential efficacy. Subjects with higher Th40 levels had low or undetectable C-peptide, higher (>7.0%) HbA1c, and elevated inflammatory cytokines. Th40 levels were significantly higher in subjects diagnosed before age eighteen. OPT101 treatment significantly reduced Th40 percentages without cell ablation, increased Treg levels, and decreased inflammatory cytokines. Serum blood glucose levels and HbA1c were significantly reduced by visit 8 in treated subjects. In two subjects, 11 and 13 years post-diagnosis, with undetectable C-peptide at screening, C-peptide became detectable post-treatment. Conclusions: OPT101 proved safe and effective in human T1D subjects with only mild and a few moderate adverse events. In this short-term study, OPT101 improved beta cell functions thus warranting further exploration. Full article

Recurrent pregnancy loss (RPL) continues to be a significant challenge in reproductive medicine, particularly in women for whom standard examinations do not reveal a conclusive underlying reason. There is growing evidence that several instances may result from nuanced alterations in the endometrial milieu, particularly with decidualization and maternal–fetal immune tolerance. In recent years, vitamin D has gained recognition for its significance in early pregnancy, serving not only as a regulator of calcium metabolism but also as an active contributor to endometrial and immunological functions. The human endometrium exhibits the vitamin D receptor (VDR) and the enzyme CYP27B1, facilitating the local activation and signaling of vitamin D inside the uterine milieu. Experimental investigations have shown that vitamin D influences many processes critical for effective implantation and placentation, including stromal cell differentiation, cytokine equilibrium, trophoblast invasion, oxidative stress responses, and immune cell communication. Aberrant vitamin D signaling has been associated with heightened inflammatory activity, impaired decidual transformation, altered uterine natural killer cell functionality, and alteration of the Treg/Th17 equilibrium, all of which have been implicated in recurrent pregnancy loss. Concurrently, there is an increasing emphasis on the association between vitamin D and mitochondrial function as well as oxidative stress in decidual and endometrial cells. Interruption of these pathways may influence implantation and early embryonic development by impacting cellular metabolism and immunological control at the maternal–fetal interface. The clinical interest in vitamin D supplementation for women experiencing repeated reproductive failure is increasing; nevertheless, the existing results are conflicting, mostly due to the predominance of research focusing on circulating vitamin D levels rather than localized tissue-specific processes. Our review encapsulates new findings about the function of vitamin D in endometrial biology and reproductive immune regulation, emphasizing its involvement in decidualization, inflammatory signaling, oxidative stress, and maternal–fetal immunological tolerance in recurrent pregnancy loss. The potential ramifications for assisted reproduction and forthcoming tailored therapy techniques are also examined. Full article

Regulatory CD4+ T cells (Tregs) are essential for immune tolerance, tissue repair, and control of inflammation, but functional human Tregs cannot be identified reliably by a single protein. This targeted narrative review evaluates protein-level and proteomics-supported Treg signatures with explicit attention to species, sample source, analytical platform, validation strategy, and intended use. Primary human LC-MS/MS studies reveal pathway-level differences involving T-cell receptor signaling, metabolism, lysosomal activity, and lineage protection, whereas murine proteomic studies provide mechanistic candidates such as Themis1 but do not establish human biomarkers. CyTOF, functional single-cell protein profiling, spatially resolved protein imaging, and multi-omics further resolve phenotypic and tissue heterogeneity. Established CD25high/CD127low/FOXP3-based panels support enrichment and phenotyping; CTLA-4, ICOS, TIGIT, GITR, PD-1, chemokine receptors, suppressive enzymes, metabolic proteins, and emerging candidates report functional or tissue states but are not Treg-exclusive. Cancer currently provides the strongest tissue-level and prognostic evidence, whereas data in healthy aging, cardiovascular and metabolic disease, osteoarthritis, and neurodegeneration remain heterogeneous and mainly exploratory. Across contexts, validated diagnostic sensitivity, specificity, reference ranges, prospective clinical utility, and inter-laboratory reproducibility are largely absent. Treg immunoproteomics is therefore best regarded as a discovery and stratification framework rather than a standardized clinical diagnostic test. Full article

Background/Objectives: Cancer vaccines represent the next frontier in immunotherapy, aiming to elicit long-lasting protective anti-tumor immune responses. Human epidermal growth factor receptor 2 (HER2) is a well-established therapeutic target in breast cancer. Active immunization with HER2-displaying M13 bacteriophages can induce a therapeutic immune response against HER2-positive breast cancer, offering a promising alternative to trastuzumab. However, the duration of anticancer immune protection triggered by anti-HER2 phage-based vaccines is limited by tumor-immune suppressive mechanisms. Methods: In this study, two vaccination cycles with ECTM phages displaying the extracellular (EC) and transmembrane (TM) domains of human HER2 were combined with palbociclib, a CDK4/6 inhibitor, to enhance antitumor immunity in the clinically relevant Δ16HER2 transgenic preclinical model of breast cancer. Results: The proposed combination treatment resulted in a better and long-lasting control of tumor growth rate and multiplicity than either palbociclib or phage vaccination alone, correlating with a significantly stronger anti-HER2 humoral response (IgG2a isotype). Analysis of the tumor immune infiltrate revealed an increased presence of CD8⁺ T cells concomitant with a reduction in FoxP3⁺ regulatory T cells (Tregs) in tumors explanted from mice receiving the combination therapy. Conclusions: These preclinical results provide a rationale for the clinical translation of CDK4/6 inhibitors combined with anti-HER2 active immunotherapies in breast cancer, as they may yield sustained antitumor responses by reverting the immunosuppressive tumor environment. Full article

FOXP3 is the master transcriptional regulator of regulatory T cells (Tregs) and is expressed in humans as two main alternatively spliced isoforms: full-length FOXP3 (FOXP3-FL) and the exon 2-deficient variant (FOXP3-Δ2). While the role of these isoforms has been mainly studied in CD4⁺ T cells, their distribution across peripheral blood leukocyte populations and their relationship with immune checkpoint expression remain incompletely defined. In this study, we used a multiparametric flow cytometry panel allowing isoform-specific detection of FOXP3-FL and FOXP3-Δ2, together with PD-1 and CTLA-4, to analyze peripheral blood samples from six healthy donors under basal conditions. Major leukocyte populations, including CD4⁺CD25⁺ and CD4⁺CD25⁻ T cells, CD8⁺ T cells, monocytes, and neutrophils, were evaluated. FOXP3-FL predominated in CD4⁺CD25⁺ T cells, whereas FOXP3-Δ2 was more frequently detected in CD8⁺ T cells, monocytes, and neutrophils. However, the absolute frequencies of these FOXP3-Δ2-positive populations were low, consistent with the overall low levels of FOXP3 expression observed in these cell types. In CD4⁺ T-cell subsets, PD-1 expression was generally higher than CTLA-4, regardless of FOXP3 isoform, and FOXP3-Δ2⁺ cells showed relatively higher PD-1 expression compared to FOXP3-FL⁺ cells. In contrast, checkpoint expression in non-CD4⁺ populations was limited. The observed FOXP3-FL⁺/FOXP3-Δ2⁺ ratios across immune cell populations were consistent with a predominant role of FOXP3-FL in maintaining immune tolerance under basal conditions; whether these patterns are preserved or altered in pathological settings warrants further investigation. These results provide a descriptive overview of FOXP3 isoform distribution and checkpoint expression across peripheral blood immune cell subsets in healthy individuals, which may serve as a reference for future studies in immune-mediated diseases. Full article

Regulatory T cells (Tregs) play a key role in immune tolerance and are promising targets for treating immune-mediated diseases. This study investigated the direct effects of PEGylated graphene oxide nanoparticles (LP-GO, BP-GO at 5–25 μg/mL) and fullerenol C₆₀(OH)₂₄ (25–200 μg/mL) on human Treg viability and differentiation in vitro. Tregs were induced from peripheral blood CD4⁺ T cells using IL-2, TGF-β, and CD2/CD3/CD28 activation beads for 72 h with nanoparticles. Assessments included viability, apoptosis (Zombie aqua/Annexin V), phenotype (CD45⁺CD4⁺CD25⁺CD127^dim/−FOXP3⁺), nanoparticle sorption (intrinsic fluorescence), and IL-10 production. Neither PEGylated graphene oxide nor fullerenol C₆₀(OH)₂₄ affected T-helper (CD4⁺) viability (95.35–96.15%) nor early/late apoptosis levels. Despite this, we found a decrease in the percentage of CD4⁺ cells in cultures exposed to 50–200 μg/mL of fullerenol C₆₀(OH)₂₄. The percentage and absolute number of Treg cells decreased with 100–200 μg/mL of fullerenol, while IL-10 levels declined following treatment with 200 μg/mL of the same nanoparticles. Graphene oxide nanoparticles showed virtually no localization within or on cells. However, T helper and Treg cells demonstrated concentration-dependent sorption of fullerenol C₆₀(OH)₂₄ at concentrations of 100–200 μg/mL without a reduction in viability. These findings demonstrate good in vitro biocompatibility of the nanoparticles at pharmacological concentrations up to 25 μg/mL, alongside the inhibition of Treg differentiation with 100–200 μg/mL of fullerenol C₆₀(OH)₂₄. Full article

Hepatocellular carcinoma (HCC) is a leading cause of cancer mortality worldwide, increasingly driven by metabolic dysfunction-associated steatotic liver disease alongside viral and alcohol-related cirrhosis. The tolerogenic immune environment of the liver enables tumor immune escape, with regulatory T cells (Tregs) playing a central role. This review synthesizes human-focused evidence (tissues, blood, clinical cohorts, and single-cell/spatial studies) through September 2025 to define how Tregs are recruited, maintained, and functionally deployed in HCC. Across datasets, intratumoral effector-like Tregs (eTregs) expressing ICOS, CTLA-4, CCR8, and CD39/CD73 accumulate within tumors and co-localize with exhausted cytotoxic PD-1^hi CD8⁺ T cells and suppressive myeloid cells. Recruitment is driven mainly by CCL20–CCR6 and CCL22/CCL17–CCR4 signaling, while CCR8 marks highly suppressive tumor-resident Tregs. Their persistence is supported by TGF-β, IL-10, IL-35, adenosine signaling, IL-2 sequestration, and metabolic adaptation. Spatial biomarkers, including ICOS⁺/CCR8⁺ eTreg density and CD8:Treg ratios, associate with prognosis and emerging immunotherapy responses. Etiology further shapes immune architecture: HBV-related HCC often forms Treg-exhausted T-cell niches around viral antigens, whereas MASLD/MASH promotes stromal and metabolic barriers that may reduce PD-(L)1 efficacy. Current treatments (PD-(L)1 blockade with anti-VEGF or CTLA-4, and some TKIs) intersect with Treg biology, while emerging strategies targeting CCR8, CCR4, ICOS, or the adenosine pathway aim to selectively disrupt intratumoral eTreg networks. This review underscores that an etiology-aware, spatial-biomarker framework may guide the integration of selective Treg targeting with PD-(L)1-based therapies in HCC. Full article

Successful embryo implantation requires dynamic, bidirectional communication between a developmentally competent blastocyst and a receptive endometrium, integrating hormonal, molecular, and immunologic signals. Increasing evidence indicates that endometrial receptivity is critically dependent on a specialized immune microenvironment that supports trophoblast invasion while maintaining maternal tolerance. This review synthesizes current knowledge on the immunologic regulation of implantation, with emphasis on uterine natural killer (uNK) cells, regulatory T cells (Tregs), macrophages, dendritic cells, and cytokine networks. We further examine intracellular signaling pathways—including JAK/STAT, PI3K/AKT, NF-κB, and MAPK—that integrate immune and decidual responses. The bidirectional embryo–endometrium dialogue is explored through embryo-derived mediators such as human chorionic gonadotropin (hCG), cytokines, growth factors, and extracellular vesicles. The endometrium is increasingly recognized as a biosensor of embryo quality, selectively supporting viable embryos. Disruption of this complex communication network is implicated in recurrent implantation failure and early pregnancy loss. Despite substantial mechanistic advances, clinical translation remains limited. Emerging strategies, including immune profiling, microbiome modulation, and extracellular vesicle-based diagnostics, hold promise for precision reproductive medicine. Full article

Background/Objectives: CTLA-4 is a key checkpoint of peripheral immune regulation, yet its biology cannot be reduced to inhibitory signaling alone. This review discusses CTLA-4 as a dynamic regulatory pathway shaped by ligand handling, intracellular trafficking, recycling, and cell-type-specific function, and examines how these features link molecular mechanism to human disease and therapy. Methods: We synthesized the structural, mechanistic, translational, and clinical literature spanning CTLA-4 molecular biology, cell-type-specific function, inborn errors of immunity, polygenic autoimmunity, transplantation, cancer immunotherapy, and immune-related adverse events. Results: CTLA-4 function depends on surface availability, trans-endocytosis of CD80/CD86, and tight control of endosomal trafficking. These features help explain why CTLA-4 haploinsufficiency, LRBA deficiency, and DEF6 deficiency converge clinically despite different upstream lesions, and why subtler CTLA-4 variation contributes to polygenic autoimmunity. Therapeutic studies also provide mechanistic insight. Abatacept can partly replace pathway function in monogenic disease, whereas belatacept highlights the limits of ligand blockade when endogenous coinhibition is also lost. In oncology, anti-CTLA-4 antibodies act through a more complex interplay involving checkpoint blockade, Fc biology, intratumoral Treg depletion, and receptor recycling. Emerging next-generation agents aim to retain antitumor activity while reducing systemic toxicity through more selective use of these mechanisms. Conclusions: Rather than a static inhibitory receptor, CTLA-4 is better viewed as a context-dependent regulatory pathway whose function depends on trafficking, surface availability, and cellular context. This perspective links molecular mechanism to clinical phenotype and supports more precise CTLA-4-targeted therapy. Full article

Background/Objectives: Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by progressive cognitive decline and chronic neuroinflammation. Increasing evidence suggests that the imbalance between pro-inflammatory Th17 cells and anti-inflammatory regulatory T (Treg) cells plays a critical role in AD pathogenesis. However, a comprehensive synthesis of how natural compounds modulate Th17/Treg balance in AD remains lacking. This review aims to summarize current preclinical evidence on Th17/Treg dysregulation and evaluate the immunomodulatory potential of natural compounds in AD. Methods: This review focuses on preclinical evidence derived from experimental AD models and related inflammatory models to evaluate how natural compounds modulate Th17/Treg balance, neuroinflammation, and cognitive function, with an emphasis on underlying molecular and immunometabolic mechanisms. Results: Th17/Treg imbalance contributes significantly to AD-associated neuroinflammation and disease progression. Representative natural compounds, including paeoniflorin, quercetin, and ganoderic acid A, have demonstrated the ability to rebalance Th17/Treg responses, suppress neuroinflammation, and improve neuronal survival in experimental models. These compounds are highlighted due to their relatively stronger evidence in AD-related models and more clearly defined immunomodulatory mechanisms. These effects are partially mediated through modulation of key signaling pathways and immunometabolic reprogramming. Conclusions: Targeting Th17/Treg balance with natural compounds represents a promising multi-target immunomodulatory strategy for AD. However, most current evidence is derived from preclinical or non-AD models, and clinical validation remains limited. Future studies should prioritize AD-specific models and translational research to evaluate therapeutic potential in humans. Full article

Human T-cell leukemia virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP) is a chronic inflammatory disease driven by HTLV-1-infected CD4⁺ T cells; however, the phenotypic and functional characteristics of disease-associated T-cell subsets remain incompletely understood. We analyzed samples using flow cytometry (n = 3–5 per group) and RNA-seq (n = 13), focusing on CADM1^highCD4⁺ T cells enriched for HTLV-1-infected cells to evaluate a transferrin receptor (TfR)-expressing subset. TfR⁺CADM1^highCD4⁺ T cells were detected in both asymptomatic carriers and patients with HAM, but their frequency among CD4⁺ T cells was higher in HAM patients. These cells exhibited a Treg-like phenotype with higher Foxp3 and CTLA-4 expression than TfR⁻ cells and showed increased Ki-67 positivity, consistent with proliferation. Despite this phenotype, they produced interferon-γ, indicating inflammatory potential, while Foxp3 expression was lower in HAM patients than in asymptomatic carriers, suggesting a more inflammatory phenotype. Furthermore, TfR transcript levels (RNA-seq TPM) correlated with clinical indicators of disease activity, including neopterin and CXCL10 protein levels, and the Osame motor disability score. Collectively, these findings suggest that TfR identifies a proliferative, Foxp3-low, Treg-like inflammatory CD4⁺ T-cell subset that is associated with disease activity in HAM. Full article

Lyme disease (LD) is classically defined as a tick-borne infection caused by Borrelia burgdorferi sensu lato (Bbsl). However, accumulating evidence indicates that, beyond microbial persistence, Bbsl infection can initiate sustained immune dysregulation and post-infectious inflammatory phenotypes in a subset of patients. This narrative review integrates open-access experimental, translational, and clinical data and discusses LD within the spectrum of infection-triggered, immune-mediated processes. We review key immunopathogenic mechanisms, including dysregulated innate immune activation, type I interferon (IFN-I) signaling, T helper 1 and T helper 17 (Th1/Th17) polarization with regulatory T-cell (Treg) insufficiency, antigen persistence (notably borrelial peptidoglycan), and pathways linking infection to autoimmunity such as molecular mimicry, epitope spreading, and human leukocyte antigen (HLA)-restricted susceptibility. These mechanisms are integrated with immune-mediated clinical manifestations affecting the central nervous system (CNS), peripheral nervous system (PNS), musculoskeletal system, heart, skin, and hematologic compartment. Finally, we discuss translational implications for diagnosis, biomarker-guided stratification, and emerging therapeutic strategies that extend beyond antimicrobial therapy, while addressing current controversies and limitations. This framework supports a mechanistic model in which Lyme disease-associated morbidity in selected patients reflects persistent immune activation and dysregulated host responses triggered by infection. Full article