Search Results (308)

Considering the high plasticity of FoxP3⁺ regulatory T (Treg) cells and Interleukin (IL)-17-producing Th17 cells, we hypothesized that a Th17 inflammatory milieu may impair the functional properties of Treg cells in chronic inflammatory arthritides. Therefore, a cross-sectional explorative analysis was set up in patients with psoriatic arthritis (PsoA), rheumatoid arthritis, or spondyloarthritis to investigate the features of Th17 and Treg cells. T cell subpopulation counts, FOXP3 mRNA expression, CpG methylation of the FOXP3 gene, and the suppressive capacity of isolated Treg cells were determined. Ex vivo analysis of PsoA-derived peripheral blood lymphocytes showed a Th17-mediated inflammation. It was accompanied by demethylation of the FOXP3 promotor and Treg-specific demethylated region (TSDR) in Treg cells which, however, resulted neither in elevated FOXP3 mRNA expression nor in increased suppressive Treg cell capacity. To clarify this conundrum, in vitro stimulation of isolated Treg cells with Th17-inducing cytokines (IL-1β, IL-6, IL-23, TGFβ), recombinant IL-17, or the anti-IL-17A antibody secukinumab was performed, demonstrating that cell culture conditions polarizing towards Th17, but not IL-17 itself, impair the suppressive function of Treg cells, accompanied by diminished FOXP3 mRNA expression due to hypermethylation of the FOXP3 promotor and TSDR. This potential causal relationship between Th17 inflammation and impaired Treg cell function requires attention regarding the development of immunomodulatory therapies. Full article

Human leukocyte extract (HLE), a non-immunogenic dialyzable leukocyte preparation (<10 kDa), may serve as a safe adjuvant in immunotherapy. We investigated the effects of albendazole (ABZ), HLE, and their combination in Mesocestoides vogae infected mice, focusing on lymphoid cells in the peritoneal cavity, the site of larval proliferation and parasite-induced immunosuppression. Peritoneal lymphoid cells were analysed by flow cytometry and qPCR. Cells proliferative responses to ConA, LPS, and parasite excretory/secretory (E/S) antigens, cytokine production (ELISA), IgM and IgG isotypes in exudates and parasite antigen recognition (Western blot) were assessed. Efficacy was measured by larval burden and 14-3-3 gene expression in larvae. HLE combined with ABZ enhanced larval clearance and suppressed 14-3-3 gene expression in larvae. HLE and combination therapy increased CD3⁺ T cell frequencies, especially CD3^+high, reduced regulatory CD3+/IL-10 Tregs and expression of Foxp3⁺. All treatments diminished CD19⁺/IL-10⁺ Bregs, correlating with lower CD9 and Atf3 mRNA levels compared to infected mice. Transcription factors T-bet expression was strongly upregulated, while GATA3 was moderately elevated. IFN-γ production and T/B cell proliferation were restored after HLE and combination therapy, partially, even in the presence of E/S antigens. IgM and total IgG levels against parasite antigens declined, while Th1-associated IgG2a increased in ABZ+HLE and HLE-treated groups. Albendazole failed to reverse the immunosuppressive Treg-type immunity but was more effective in reducing Breg populations and their functions. HLE enhanced ABZ efficacy by restoring Th1 responsiveness, reducing Treg/Breg activity, and modulating antibody profiles. It represents a promising immunomodulatory adjuvant in the treatment of the infections associated with Th2/Treg-driven immunosuppression. Full article

Antibody-mediated rejection (ABMR) caused by donor-specific Abs (DSAs) is still the leading cause of late graft loss following clinical organ transplantation, and effective strategies to combat ABMR are still elusive. We previously showed that rIL-2 complexed with anti-IL-2 mAb clone JES6-1A12 (IL-2 cplx) leads to the selective expansion of regulatory T cells (Tregs) and the prolonged survival of MHC-mismatched skin allografts. Although the grafts were eventually rejected, mice failed to develop DSAs. Here, we investigated the impact of IL-2 cplx on the humoral response and germinal center (GC) reaction during allograft rejection. IL-2 cplx treatment prevents Bcl-6 upregulation, leading to suppressed development of GC T and B cells. The IL-2 cplx-induced impairment of GC development limits IgG allo-Ab production but allows for IgM synthesis. By employing a hapten–carrier system to investigate affinity maturation, we found that IL-2 cplx induces a distinct shift in specific Ab production favoring low-affinity IgM while simultaneously decreasing IgG responses. These findings illuminate the potential of IL-2 cplx therapy for inducing humoral tolerance, potentially paving the way for refining strategies aimed at preventing and treating ABMR. Full article

Background/Objectives: Chimeric antigen receptor T-cell (CAR-T) therapy is a novel form of adoptive cellular immunotherapy that involves modifying autologous T cells to recognize and target tumor-associated antigens (TAAs) on malignant cells, independent of major histocompatibility complex (MHC) restriction. Although CAR-T therapy has shown remarkable success in treating hematologic malignancies, its efficacy in solid tumors remains limited, largely due to the lack of tumor-specific antigens and the complexity of the tumor microenvironment. This review aims to explore the rationale for continuing the development of adoptive cellular therapies in head and neck cancer (HNC), offering insights into the diagnostic and therapeutic challenges associated with this heterogeneous group of malignancies. Methods: We conducted a comprehensive literature review using the PubMed database to identify relevant studies on the application of CAR-T cell therapy in the management of HNC. Results: HNC presented numerous barriers to CAR-T cell infiltration, primarily due to the unique characteristics of its tumor microenvironment (TME). The TME in HNC is notably immunosuppressive, with a lymphocytic infiltrate predominantly composed of regulatory T cells (Tregs) and natural killer (NK) cells. These immune cells typically exhibit low expression of the CD16 receptor, which plays a crucial role in mediating antibody-dependent cellular cytotoxicity (ADCC), thereby limiting the effectiveness of CAR-T cell therapy. Conclusions: This comprehensive review suggests a potential clinical applicability of CAR-T therapy in HNC management. Full article

Cell therapy is promising for heart failure treatment, with growing interest in cardiovascular progenitor cells (CPCs) from pluripotent stem cells. A major challenge is managing the immune response, due to their allogeneic source. Regulatory T cells (Treg) offer an alternative to pharmacological immunosuppression by inducing immune tolerance. This study assesses whether Treg therapy can mitigate the xeno-immune response, improving cardiac outcomes in a mouse model of human CPC intramyocardial transplantation. CPCs stimulated immune responses in allogeneic and xenogeneic settings, causing proliferation in T cell subsets. Tregs showed immunosuppressive effects on T lymphocyte populations when co-cultured with CPCs. Post infarction, CPCs were transplanted intramyocardially into an immune-competent mouse model 3 weeks after myocardial infarction. Human or murine Tregs were intravenously administered on transplantation day and three days later. Control groups received CPCs without Tregs or saline (PBS). CPCs with Tregs improved LV systolic function in three weeks, linked to reduced myocardial fibrosis and enhanced angiogenesis. This was accompanied by decreased splenocyte NK cell populations and pro-inflammatory cytokine levels in cardiac tissue. Treg therapy with CPC transplantation enhances cardiac functional and structural outcomes in mice. Though it does not directly avert graft rejection, it primarily affects NKG2D+ cytotoxic cells, indicating systemic immune modulation and remote heart repair benefits. Full article

The long-term use of immunosuppressive drugs following kidney transplantation increases the risk of life-threatening infections, malignancies, and, paradoxically, eventual allograft rejection. Therefore, achieving a balance between over-immunosuppression and under-immunosuppression is critical to optimizing patient outcomes. One promising approach is immune cell-based therapy using suppressor immune cells to modulate the immune response more precisely. Among these, regulatory T cells (Tregs) are the most extensively studied and have shown significant potential in the post-transplant setting. Tregs are broadly categorized into thymus-derived and peripherally derived subsets. Physiologically, they play key roles in maintaining immune tolerance, including in autoimmune diseases and within the tumor microenvironment. Their immunosuppressive functions are mediated through both contact-dependent and contact-independent mechanisms. Studies investigating the use of Tregs following kidney transplantation have shown encouraging results. This review summarizes the biology of Tregs and highlights current evidence supporting their role in transplant immunotherapy. Full article

Renal cell carcinoma (RCC) accounts for about 403,000 new cases and 175,000 deaths worldwide each year. Clear cell RCC (ccRCC), the most prevalent subtype, is often driven by genetic mutations, such as VHL inactivation, leading to angiogenesis and immune escape. Immune checkpoint inhibitors (ICIs) targeting PD-1, PD-L1, and CTLA-4 have transformed treatment paradigms, yet therapeutic resistance remains a critical challenge. The immunosuppressive nature of the tumor microenvironment (TME) in ccRCC plays a central role in limiting ICI efficacy. Emerging strategies aim to overcome resistance by targeting key components of the TME, including tumor-associated macrophages, regulatory T cells (Tregs), and cytokine signaling. Agents such as nivolumab, pembrolizumab, and ipilimumab have demonstrated the ability to restore T-cell activity and mitigate immune suppression, offering clinical benefit in metastatic ccRCC. However, response rates vary, highlighting the need for rational combination therapies. ICIs combined with VEGF inhibitors have shown promising outcomes in clinical trials, and novel regimens continue to be explored. Risk stratification and personalized treatment selection are increasingly important as the therapeutic landscape evolves. This review synthesizes current advances in immunotherapy for ccRCC, with a focus on mechanisms of resistance and innovative strategies to enhance immune responsiveness. A deeper understanding of TME modulation and strategic combination approaches is essential to improve survival and quality of life for patients with advanced ccRCC. Full article

Autoimmune diseases such as multiple sclerosis (MS) are characterized by a loss of self-tolerance, driven by diminished regulatory T cell (Treg) function and elevated Th1/Th17 responses. Existing therapies broadly suppress the immune system without correcting this imbalance, often leading to adverse effects. LPX3, a novel small-molecule T cell immunoglobulin and mucin domain-containing 3 and 4 (Tim-3/4) receptor agonist, was developed to restore immune tolerance via Treg induction. In this study, LPX3 was formulated into a liposomal oral delivery system, enabling efficient uptake through the gastrointestinal tract and lymphatic targeting. In vitro and in vivo analyses confirmed LPX3’s ability to expand CD4⁺Foxp3⁺ Tregs in a dose-dependent manner. In a MOG-induced experimental autoimmune encephalomyelitis (EAE) mouse model of MS, both prophylactic and therapeutic oral administration of LPX3 significantly delayed disease onset, reduced symptom severity, and improved survival. Importantly, efficacy was achieved without antigen co-delivery, indicating an antigen-independent mechanism of immune modulation. LPX3 liposomes showed deep lymph node penetration and colocalization with immune cells, supporting its functional delivery to key immunological sites. These findings suggest LPX3 is a promising candidate for treating autoimmune diseases by re-establishing immune regulation through oral, antigen-agnostic tolerance induction. Full article

Introduction: In mouse models of chronic lymphocytic leukemia (CLL), an effective anti-leukemia immune response was obtained by depleting a specific regulatory T-cell (Treg) subset. While STAT5 signaling could alter the homeostasis of naïve (nTreg) and activated (aTreg) subsets, which are capable of suppressing also CLL patients’ responses to microbial antigens, perturbed STAT3 signaling could drive CXCR5 expression in circulating T-follicular regulatory cells (Tfr) and their entry into the lymph node/tumor microenvironment. Materials and Methods: By using phospho-specific flow cytometry, we monitored STAT signaling/phosphorylation (pSTAT), in vitro responses to Sars-Cov2-antigen-specific stimulation, and circulating Treg subsets in relation to Binet stage and total tumor mass/tumor distribution (TTM/TD) scoring in 62 patients with CLL. Results: The percentage of CXCR5⁺ Treg significantly increased in patients with Binet stage B disease, and Tfr-like subsets were associated with higher TTM and lower TD. The pSTAT3 levels in CD4⁺ T-cells were only significantly increased in patients undergoing therapy. Lower nTreg percentages correlated with increased disease duration, and an increased aTreg/nTreg ratio correlated with SARS-CoV-2-antigen-induced STAT5 signaling responses. Conclusions: The results show increased amounts of circulating CXCR5⁺ Tfr-like subsets in patients with extensive lymph node involvement and augmented STAT3 signaling in patients on therapy. While STAT5 responses may drive nTreg differentiation into aTreg, nTreg decline is associated with increased disease duration. Full article

The tumor microenvironment (TME) is a unique ecosystem that surrounds tumor tissues. The TME is composed of extracellular matrix, immune cells, blood vessels, stromal cells, and fibroblasts. These environments enhance cancer development, progression, and metastasis. Recent success in immune checkpoint blockade also supports the importance of the TME and immune cells residing in the tumor niche. Although the TME can be identified in almost all cancer types, the role of the TME may not be similar among different cancer types. Regulatory T cells (Tregs) play a pivotal role in immune homeostasis and are frequently found in the TME. Owing to their suppressive function, Tregs are often considered unfavorable factors that allow the immune escape of cancer cells. However, the presence of Tregs is not always linked to an unfavorable phenotype, which can be explained by the heterogeneity and plasticity of Tregs. In this review, the current understanding of the role of Tregs in TME is addressed for each cancer cell type. Moreover, recently a therapeutic approach targeting Tregs infiltrating in the TME has been developed including drug antibody conjugate, immunotoxin, and FOXP3 inhibiting peptide. Thus, understanding the role of Tregs in the TME may lead to the development of novel therapies that directly target the TME. Full article

Background: Racotumomab-alum is an anti-idiotype vaccine targeting the NeuGcGM3 tumor-associated ganglioside. Clinical trials in advanced cancer patients have demonstrated low toxicity, high immunogenicity and clinical benefit. The goal of this study was to identify circulating biomarkers of clinical outcome. Methods: Eighteen patients with stage IIIb/IV non-small-cell lung cancer (NSCLC) were injected with racotumomab-alum as switch maintenance therapy after first-line chemotherapy. Treatment was administered until severe performance status worsening or toxicity. The frequencies of innate and adaptive lymphocytes were assessed by flow cytometry. Circulating factors were measured using multi-analyte flow assay kits. Results: The median overall survival was 16.5 months. Twenty-seven percent of patients were classified as long-term survivors. Patients with lower baseline frequencies of CD4+Tregs and central memory (CM) CD8+T cells displayed longer survival rates. Furthermore, higher baseline frequencies of NKT cells and a high CD8+T/CD4+Treg ratio were associated with longer survival. Interestingly, patients with significantly lower levels of effector memory (EM) CD8+T cells survived longer. The levels of NKT cells and terminal effector memory (EMRA) CD8+T cells were higher in long-term survivors in comparison with short-term survivors in post-immune samples. As expected, the ratio of CD8+T/CD4+Tregs showed significantly higher values during treatment in patients with clinical benefits. Regarding serum factors, pro-tumorigenic cytokines significantly increased during treatment in poor survivors. Conclusions: In advanced NSCLC patients receiving racotumomab-alum vaccine, longer survival could be associated with a unique profile of circulating lymphocyte subsets at baseline and during treatment. Additionally, certain pro-tumor-related cytokines increased in short-term survivors. These results should be confirmed in larger randomized clinical trials. This clinical trial was registered in the Cuban Clinical Trials Register (RPCE00000279). Full article

Hepatocellular carcinoma (HCC) is a major cause of cancer-related mortality worldwide. Conventional therapies are frequently limited by tumor heterogeneity and the immunosuppressive tumor microenvironment (TME). Dendritic cells (DCs), central to orchestrating antitumor immunity, have become key targets for HCC immunotherapy. This review examines the biological functions of DC subsets (cDC1, cDC2, pDC, and moDC) and their roles in initiating and modulating immune responses against HCC. We detail the mechanisms underlying DC impairment within the TME, including suppression by regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), tumor-associated macrophages (TAMs), and cancer-associated fibroblasts (CAFs). Additionally, we discuss novel DC-based therapeutic strategies, such as DC-based vaccines designed to enhance antigen presentation and T cell activation. Combining DC vaccines with immune checkpoint inhibitors (ICIs), including PD-1/PD-L1 and CTLA-4 blockers, demonstrates synergistic effects that can overcome immune evasion and improve clinical outcomes. Despite progress, challenges related to DC subset heterogeneity, TME complexity, and patient variability require the further optimization and personalization of DC-based therapies. Future research should focus on refining these strategies, leveraging advanced technologies like genomic profiling and artificial intelligence, to maximize therapeutic efficacy and revolutionize HCC treatment. By restoring DC function and reprogramming the TME, DC-based immunotherapy holds immense potential to transform the management of HCC and improve patient survival. Full article

Background: Colorectal cancer (CRC) is a leading cause of cancer-related mortality worldwide. Identifying drug targets associated with CRC is crucial for developing targeted therapies. Methods: MR (IVW, Wald ratio, weighted median, and MR-Egger) and SMR analyses were used to screen candidate genes associated with CRC risk. Further validation was performed using The Cancer Genome Atlas (TCGA) to assess gene expression patterns and prognostic significance. Additionally, immune infiltration analysis was conducted to characterize the tumor immune microenvironment. Drug prediction was performed to explore potential therapeutic interventions. Results: Eight genes were identified associated with CRC. IGFBP3, CD72, SERPINH1, CHRDL2, LRP11, and SPARCL1 were linked to an increased risk of CRC, whereas DBI and HYAL1 were associated with a decreased risk of CRC. Notably, DBI exhibited a potentially favorable immune profile, negatively correlated with Tregs and MDSCs while positively associated with activated CD8⁺ and CD4⁺ T cells. Conclusions: Eight genes were identified as associated with CRC, among which DBI exhibited a potential protective role, correlating with improved patient survival, enhanced immune activation, and increased responsiveness to immunotherapy. The remaining proteins demonstrated diverse and complex functions within the tumor immune microenvironment, providing novel insights for the development of precision diagnostics and immunotherapeutic strategies. Full article

Heart transplantation remains the gold-standard treatment for end-stage heart failure, yet long-term graft survival is hindered by chronic rejection and the morbidity and mortality caused by lifelong immunosuppression. While advances in medical and device-based therapies have reduced the overall need for transplantation, patients who ultimately require a transplant often present with more advanced disease and comorbidities. Recent advances in tolerance-inducing strategies offer promising avenues to improve allograft acceptance, while minimizing immunosuppressive toxicity. This review explores novel approaches aiming to achieve long-term immunological tolerance, including co-stimulation blockade, mixed chimerism, regulatory T-cell (Treg) therapies, thymic transplantation, and double-organ transplantation. These strategies seek to promote donor-specific unresponsiveness and mitigate chronic rejection. Additionally, expanding the donor pool remains a critical challenge in addressing organ shortages. Innovations such as ABO-incompatible heart transplantation are revolutionizing the field by increasing donor availability and accessibility. In this article, we discuss the mechanistic basis, clinical advancements, and challenges of these approaches, highlighting their potential to transform the future of heart transplantation with emphasis on clinical translation. Full article

Gene therapy holds great promise for treating various congenital rare diseases. However, immunogenicity against viral vectors used in gene therapy remains a challenge, impacting both the safety and efficacy of gene therapy products. Neutralizing antibodies against the vector capsid proteins impact the ability to re-dose patients, which a growing body of evidence suggests might be required for some indications and certain younger patient populations. In this communication, we report a novel dual-acting liposomal formulation that induces immune tolerance toward adeno-associated virus 9^null (AAV9^null) capsid proteins. We present in silico data on our first- and second-generation Tim agonist molecules as well as in vitro and in vivo data supporting the generation of antigen-specific regulatory T cells (Tregs) as well as abrogation of antibody response to AAV9^null capsid in our animal models. These early data are encouraging and may offer a new solution to mitigate the immunogenicity induced by gene therapy products. Full article