Search Results (2,046)

Thymic regulatory lymphocytes (Tregs) are rare in the normal periphery where they mediate immune tolerance but accumulate in the tumor immune microenvironment (TIM), reducing the antitumor response. Subtypes of classical Hodgkin lymphoma (CHL) are characterized by a minority of malignant Hodgkin and Reed–Sternberg cells (HRS) and an abundant TIM that plays a key role in modulating the disease. CHL is related to the Epstein–Barr virus (EBV), whose oncogenes influence the growth of HRS. We analyzed the number of T lymphocytes expressing the regulatory marker FOXP3 in CHL with regard to EBV status. The tumor tissue of 182 patients was stained by double immunohistochemistry for FOXP3, CD4, and CD8, and the number of different phenotypes was analyzed microscopically. EBV status was determined by EBER in situ hybridization. EBV-positive CHL was confirmed in 28% of patients and was associated with mixed cellularity (MC) (p < 0.001), older age (p < 0.001), and unfavorable outcomes (p = 0.038). The number of CD8+ T lymphocytes differed according to the EBV status of MC and nodular sclerosis (NS), and was the lowest in EBV-negative NS (p = 0.001). Likewise, the numbers for FOXP3 and FOXP3/CD4 were different, and were the lowest in EBV-negative MC (p = 0.035 and p = 0.041, respectively). Values above a median of FOXP3 and CD4 are associated with longer progression-free survival (p = 0.039 and p < 0.001, respectively). EBV impacts the composition of T cell phenotypes in TIM, among which the amount of CD4 and FOXP3 is prognostically valuable. Full article

The modulation of cellular phenotypes within adipose tissue provides a potential means for therapeutic intervention for diabetes. Endogenous interleukin-10 (IL-10) protects against diet-induced insulin resistance. We examined the effects and mechanisms of action of IL-10-treated adipose-derived stromal cells on diabetes-induced insulin resistance and liver gluconeogenesis. We harvested stromal vascular fractions (SVFs) from the adipose tissue of diabetic (Lepr^db/db) mice and treated them with IL-10 in vitro. SVFs treated with 10 or 100 ng of IL-10 were injected into the inguinal adipose tissue of Lepr^db/db mice. IL-10 treatment suppressed the mRNA expression of IL-6, IL-33, CCL2, TNF-α, and IL-1β. Additionally, it suppressed the protein expression of IL-6, pmTOR, pJNK, and pNF-κB but enhanced Foxp3 mRNA expression in SVFs from diabetic mice. Meanwhile, IL-10 treatment repressed CCL2 and PDGFRα expression in adipose tissue macrophages (ATMs) and IL-6 expression in non-ATMs but increased the Foxp3 and IL-10 mRNA expression of ATMs from diabetic mice. Injection of IL-10-treated SVFs decreased the IL-6, IL-33, CCL2, IL-1β, and CCL2 but enhanced the Foxp3 and IL-10 mRNA expression of adipose tissue from Lepr^db/db mice. Furthermore, injection of IL-10-treated SVFs increased CD4⁺ regulatory T cells (Tregs) in SVFs and adipose IL-10 levels and suppressed plasma adiponectin levels and DPP4 activity in diabetic mice. Injection of IL-10-treated SVFs decreased hepatic G6PC and PCK1 mRNA expression and increased Akt activation, STAT3 phosphorylation in the liver, and glucose tolerance in diabetic mice. Our data suggest that IL-10 treatment decreases inflammation in adipose SVFs of diabetic mice. Injection of IL-10-treated SVFs into the adipose tissue decreased diabetes-induced gluconeogenesis gene expression, DPP4 activity, and insulin resistance by enhancing Treg cells in diabetic mice. These data suggest that IL-10-treated adipose stromal vascular cells could be a promising therapeutic strategy for diabetes mellitus. Full article

Pro-B- and pre-B-cells are consecutive entities in early B-cell development, representing cells of origin for B-cell precursor acute lymphoid leukemia (BCP-ALL). Normal B-cell differentiation is critically regulated by specific transcription factors (TFs). Accordingly, TF-encoding genes are frequently deregulated or mutated in BCP-ALL. Recently, we described TF-codes which delineate physiological activities of selected groups of TF-encoding genes in hematopoiesis including B-cell development. Here, we exploited these codes to uncover regulatory connections between particular TFs in pro-B- and pre-B-cells via an analysis of developmental TFs encoded by NKL and TALE homeobox genes and by ETS and T-box genes. Comprehensive expression analyses in BCP-ALL cell lines helped identify validated models to study their mutual regulation in vitro. Knockdown and overexpression experiments and subsequent RNA quantification of TF-encoding genes in selected model cell lines revealed activating, inhibitory or absent connections between nine TFs operating in early B-cell development, including HLX, MSX1, IRX1, MEIS1, ETS2, ERG, SPIB, EOMES, and TBX21. In addition, genomic profiling revealed BCP-ALL subtype-specific copy number alterations of ERG at 21q22, while a deletion of the TGFbeta-receptor gene TGFBR2 at 3p24 resulted in an upregulation of EOMES. Finally, we combined the data to uncover gene regulatory networks which control normal differentiation of early B-cells, collectively endorsing more detailed evaluation of BCP-ALL subtypes. Full article

Calcification plays a key role in biological processes, and breakdown of the regulatory mechanism results in a pathological state such as ectopic calcification. We hypothesized that ENPP1, the enzyme that produces the calcification inhibitor pyrophosphate, is transcriptionally regulated by Nrf2, and that Nrf2 activation augments ENPP1 expression to inhibit ectopic calcification. Cell culture experiments were performed using mouse osteoblastic cell line MC3T3-E1. Nrf2 was activated by 5-aminolevulinic acid and sodium ferrous citrate. Nrf2 overexpression was induced by the transient transfection of an Nrf2 expression plasmid. ENPP1 expression was monitored by real-time RT-PCR. Because the promoter region of ENPP1 contains several Nrf2-binding sites, chromatin immunoprecipitation using an anti-Nrf2 antibody followed by real-time PCR (ChIP-qPCR) was performed. The relationship between Nrf2 activation and osteoblastic differentiation was examined by alkaline phosphatase (ALP) and Alizarin red staining. We used mice with a hypomorphic mutation in ENPP1 (ttw mice) to analyze whether Nrf2 activation inhibits ectopic calcification. Nrf2 and Nrf2 overexpression augmented ENPP1 expression and inhibited osteoblastic differentiation, as indicated by ALP expression and calcium deposits. ChIP-qPCR showed that some putative Nrf2-binding sites in the ENPP1 promoter region were bound by Nrf2. Nrf2 activation inhibited ectopic calcification in mice. ENPP1 gene expression was transcriptionally regulated by Nrf2, and Nrf2 activation augmented ENPP1 expression, leading to the attenuation of osteoblastic differentiation and ectopic calcification in vitro and in vivo. Nrf2 activation has a therapeutic potential for preventing ectopic calcification. Full article

Background: Relapsed medulloblastoma (MB) poses a significant therapeutic challenge due to its highly immunosuppressive tumor microenvironment. Immune checkpoint inhibitors (ICIs) have struggled to mitigate this challenge, largely due to low T-cell infiltration and minimal PD-L1 expression. Identifying the mechanisms driving low T-cell infiltration is crucial for developing more effective immunotherapies. Methods: We utilize a syngeneic mouse model to investigate the tumor immune microenvironment of MB and compare our findings to transcriptomic and proteomic data from human MB. Results: Flow cytometry reveals a notable presence of CD45^hi/CD11b^hi macrophage-like and CD45^int/CD11b^int microglia-like tumor-associated macrophages (TAMs), alongside regulatory T-cells (T_regs), expressing high levels of the inhibitory checkpoint molecule VISTA. Compared to sham control mice, the CD45^hi/CD11b^hi compartment significantly expands in tumor-bearing mice and exhibits a myeloid-specific signature composed of VISTA, CD80, PD-L1, CTLA-4, MHCII, CD40, and CD68. These findings are corroborated by proteomic and transcriptomic analyses of human MB samples. Immunohistochemistry highlights an abundance of VISTA-expressing myeloid cells clustering at the tumor–cerebellar border, while T-cells are scarce and express FOXP3. Additionally, tumor cells exhibit immunosuppressive properties, inhibiting CD4 T-cell proliferation in vitro. Identification of VISTA’s binding partner, VSIG8, on tumor cells, and its correlation with increased VISTA expression in human transcriptomic analyses suggests a potential therapeutic target. Conclusions: This study underscores the multifaceted mechanisms of immune evasion in MB and highlights the therapeutic potential of targeting the VISTA–VSIG axis to enhance anti-tumor responses. Full article

The different susceptibility to HIV-1 infection in U937 cells—permissive (Plus) or nonpermissive (Minus)—is linked to the expression in Minus cells of interferon (IFN)-γ inducible antiviral factors such as tripartite motif-containing protein 22 (TRIM22) and class II transactivator (CIITA). CIITA interacts with Cyclin T1, a key component of the Positive-Transcription Elongation Factor b (P-TEFb) complex needed for the efficient transcription of HIV-1 upon interaction with the viral transactivator Tat. TRIM22 interacts with CIITA, recruiting it into nuclear bodies together with Cyclin T1. A 50 kDa Cyclin T1 was found only in Minus cells, alongside the canonical 80 kDa protein. The expression of this truncated form remained unaffected by proteasome inhibitors but was reduced by IFNγ treatment. Unlike the nuclear full-length protein, truncated Cyclin T1 was also present in the cytoplasm, and this subcellular localization correlated with its capacity to inhibit Tat-mediated HIV-1 transcription. The 50 kDa Cyclin T1 in Minus cells likely contributes to their non-permissive phenotype by acting as a dominant negative factor, disrupting P-TEFb complex formation and function. Its reduction upon IFNγ treatment suggests a regulatory loop by which its inhibitory role on HIV-1 replication is then exerted by the IFNγ-induced CIITA, which binds to the canonical Cyclin T1, displacing it from the P-TEFb complex. Full article

Background: Solid organ transplantation is hindered by immune-mediated chronic graft dysfunction and the side effects of immunosuppressive therapy. Regulatory T cells (Tregs) are crucial for modulating immune responses post-transplantation; however, the transfer of polyspecific Tregs alone is insufficient to induce allotolerance in rodent models. Methods: To enhance the efficacy of adoptive Treg therapy, we investigated different immune interventions in the recipients. By utilizing an immunogenic skin transplant model and existing transplantation medicine reagents, we facilitated the clinical translation of our findings. Specifically, antigen-specific Tregs were used. Results: Our study demonstrated that combining the available induction therapies with drug-induced T-cell proliferation due to lymphopenia effectively increased the Treg/T effector ratios. This results in significant Treg accumulation within the graft, leading to long-term tolerance after the transfer of antigen-specific Tregs. Importantly, all the animals achieved operational tolerance, which boosted the presence of adoptively transferred Tregs within the graft. Conclusions: This protocol offers a means to establish tolerance by utilizing antigen-specific Tregs. These results have promising implications for future trials involving adoptive Treg therapy in organ transplantation. Full article

Herbal and complementary medicine are frequently integrated with conventional medicine. We aim to report a case of severe herbal-induced liver injury (HILI) due to chronic use of green tea and protein shake. We present both clinical and laboratory evidence implicating mitochondrial toxicity and an immune response leading to a hypersensitivity reaction to the products. We have recently treated a 39-year-old man with hepatotoxicity resulting from a combination of a green tea-containing powder and a branched-chain amino acid supplement that was commenced 2 months previously. The hepatotoxicity resolved by stopping the consumption of these products and no other cause was detected. We decided to perform a lymphocyte toxicity assay (LTA) to determine if there was laboratory support for this diagnosis. LTA (% toxicity) represents the response of the mitochondria to toxic injury. To determine the role of the proinflammatory and anti-inflammatory cytokines and chemokines in the patient’s reaction, we measured the level of cytokines and chemokine in the media of growing cells, exposed to each product or to a combination of products. The increased cytokines and chemokines are presented as the x-fold elevations from the upper limit of normal (ULN) for matrix metalloproteinase (MMP) (pg/mL × 1.5 ULN) and interleukin (IL)-1β (pg/mL × 1.8 ULN). Higher elevations were found for interferon (IFN)-β, IFN-γ, IL-8, IL 13, IL-15 (pg/mL × 2 ULN), regulated upon activation, normal T cell expressed and presumably secreted (RANTES) (pg/mL × 2 ULN), and nuclear factor (NFκB) (pg/mL × 3 ULN). The highest increases were for vascular endothelial factor (VEGF) (pg/mL × 10 ULN), tumor necrosis factor (TNF)-α, and tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) (pg/mL × 13 ULN). An examination of cellular markers showed the difference between programmed cell death (apoptosis) and cell death due to necrosis. In our case, cytokeratin—ccK18 (M-30) U/L was within the normal limits, suggesting that apoptosis was normal, while ccK8(M65) U/L was elevated at 1.5 × ULN. This result implies that upon the treatment of the patient’s lymphocytes with the products, the mechanism of toxicity is necrosis. In susceptible individuals, the combination of protein and herbal tea produces mitochondrial toxicity and a strong T-lymphocyte-1 response, leading to HILI. There is a need of international reporting of adverse drug reactions by clinicians, laboratories, and pharmaceutical manufacturers to drug regulatory authorities. This requires internationally accepted standard definitions of reactions, as well as criteria for assessment. Full article

IgG4-RD is a multisystem fibroinflammatory disease characterized by the infiltration of tissues by IgG4 plasma cells. Combined skin and biliary tract involvement in IgG4-RD has not been described. We present perhaps the most comprehensive analysis of lymphocyte subsets in the first case of IgG4-related generalized skin rash and first case of combined skin and biliary tract manifestations. A 55-year-old male presented with painful jaundice and generalized macular pigmented pruritic eruptions, and CT abdomen revealed biliary obstruction. Ampulla and skin biopsies were subjected to histology and immunostaining. Naïve, central memory (T_CM), effector memory (T_EM), terminally differentiated effector memory (T_EMRA) subsets of CD4+ and CD8+ T cells, T follicular helper subsets, naïve, transitional, marginal zone (MZ), germinal center (GC), IgM memory, and class-switched memory (CSM) B cells, and T follicular regulatory, regulatory B cells, CD4 Treg, and CD8 Treg were analyzed. Serum IgG4 was elevated at 448 mg/dL. Ampula biopsy showed lamina propria fibrosis and increased IgG4-positive plasma cells. Skin punch biopsy showed lymphoplasmacytic infiltrates with a 67% ratio of IgG4+:IgG+ plasma cells. CD4+T_N and CD4+T_CM decreased, whereas CD4+T_EM increased. Naïve B cells increased; transitional, MZ, CSM, GC B cells, and plasmablasts decreased compared to control. CD4 Treg increased, whereas CD8 Treg and Breg decreased. In conclusion, IgG-RD may present with combined biliary tract and generalized dermatological manifestations. Changes in regulatory lymphocytes suggest their role in the pathogenesis of IgG4-RD. Full article

CD4+ T lymphocytes play a key role in the modulation of the immune response by orchestrating both effector and regulatory functions. The effect of metformin on the immunometabolism of CD4+ T lymphocytes has been scarcely studied, and its impact under high glucose conditions, particularly concerning effector responses and glucose metabolism, remains unknown. This study aims to evaluate the effect of metformin on the modulation of the effector functions and glucose metabolism of CD4+ T lymphocytes under normo- and hyperglycemic conditions. CD4+ T lymphocytes, obtained from peripheral blood from healthy volunteers, were anti-CD3/CD28-activated and cultured for 4 days with three concentrations of metformin (0.1 mM, 1 mM, and 5 mM) under normoglycemic (5.5 mM) and hyperglycemic (25 mM) conditions. Effector functions such as proliferation, cell count, cell cycle analysis, activation markers and cytokine secretion were analyzed by flow cytometry. Glucose uptake was determined using the 2-NBDG assay, and levels of glucose, lactate, and phosphofructokinase (PFK) activity were assessed by colorimetric assays. Metformin at 5 mM restrained the cell counts and proliferation of CD4+ T lymphocytes by arresting the cell cycle in the S/G2 phase at the beginning of the cell culture, without affecting cell activation, cytokine production, and glucose metabolism. In fact, CD69 expression and IL4 secretion by CD4+ T lymphocytes was higher in the presence of 5 mM than the untreated cells in both glucose conditions. Overall, metformin inhibited proliferation through mechanisms associated with cell cycle arrest, leading to an increase in the S/G2 phases at the expense of G1 in activated CD4+ T lymphocytes in normo- and hyperglycemic conditions. Despite the cell cycle arrest, activated CD4+ T lymphocytes remained metabolically, functionally, and phenotypically activated. Full article

Food allergy (FA) is estimated to impact up to 10% of the population and is a growing health concern. FA results from a failure in the mucosal immune system to establish or maintain immunological tolerance to innocuous dietary antigens, IgE production, and the release of histamine and other mediators upon exposure to a food allergen. Of the different FAs, peanut allergy has the highest incidence of severe allergic responses, including systemic anaphylaxis. Despite the recent FDA approval of peanut oral immunotherapy and other investigational immunotherapies, a loss of protection following cessation of therapy can occur, suggesting that these therapies do not address the underlying immune response driving FA. Our lab has shown that liver-directed gene therapy with an adeno-associated virus (AAV) vector induces transgene product-specific regulatory T cells (Tregs), eradicates pre-existing pathogenic antibodies, and protects against anaphylaxis in several models, including ovalbumin induced FA. In an epicutaneous peanut allergy mouse model, the hepatic AAV co-expression of four peanut antigens Ara h1, Ara h2, Ara h3, and Ara h6 together or the single expression of Ara h3 prevented the development of a peanut allergy. Since FA patients show a reduction in Treg numbers and/or function, we believe our approach may address this unmet need. Full article

The regulatory approvals of tumor-agnostic therapies have led to the re-evaluation of the drug development process. The conventional models of drug development are histology-based. On the other hand, the tumor-agnostic drug development of a new drug (or combination) focuses on targeting a common genomic biomarker in multiple cancers, regardless of histology. The basket-like clinical trials with multiple cohorts allow clinicians to evaluate pan-cancer efficacy and toxicity. There are currently eight tumor agnostic approvals granted by the Food and Drug Administration (FDA). This includes two immune checkpoint inhibitors, and five targeted therapy agents. Pembrolizumab is an anti-programmed cell death protein-1 (PD-1) antibody that was the first FDA-approved tumor-agnostic treatment for unresectable or metastatic microsatellite instability-high (MSI-H) or deficient mismatch repair (dMMR) solid tumors in 2017. It was later approved for tumor mutational burden-high (TMB-H) solid tumors, although the TMB cut-off used is still debated. Subsequently, in 2021, another anti-PD-1 antibody, dostarlimab, was also approved for dMMR solid tumors in the refractory setting. Patients with fusion-positive cancers are typically difficult to treat due to their rare prevalence and distribution. Gene rearrangements or fusions are present in a variety of tumors. Neurotrophic tyrosine kinase (NTRK) fusions are present in a range of pediatric and adult solid tumors in varying frequency. Larotrectinib and entrectinib were approved for neurotrophic tyrosine kinase (NTRK) fusion-positive cancers. Similarly, selpercatinib was approved for rearranged during transfection (RET) fusion-positive solid tumors. The FDA approved the first combination therapy of dabrafenib, a B-Raf proto-oncogene serine/threonine kinase (BRAF) inhibitor, plus trametinib, a mitogen-activated protein kinase (MEK) inhibitor for patients 6 months or older with unresectable or metastatic tumors (except colorectal cancer) carrying a BRAF^V600E mutation. The most recent FDA tumor-agnostic approval is of fam-trastuzumab deruxtecan-nxki (T-Dxd) for HER2-positive solid tumors. It is important to identify and expeditiously develop drugs that have the potential to provide clinical benefit across tumor types. Full article

Autoimmunity refers to an organism’s immune response against its own healthy cells, tissues, or components, potentially leading to irreversible damage to vital organs. Central and peripheral tolerance mechanisms play crucial roles in preventing autoimmunity by eliminating self-reactive T and B cells. The disruption of immunological tolerance, characterized by the failure of these mechanisms, results in the aberrant activation of autoreactive lymphocytes that target self-tissues, culminating in the pathogenesis of autoimmune disorders. Genetic predispositions, environmental exposures, and immunoregulatory disturbances synergistically contribute to the susceptibility and initiation of autoimmune pathologies. Within the realm of immune therapies for autoimmune diseases, cytokine therapies have emerged as a specialized strategy, targeting cytokine-mediated regulatory pathways to rectify immunological imbalances. Proinflammatory cytokines are key players in inducing and propagating autoimmune inflammation, highlighting the potential of cytokine therapies in managing autoimmune conditions. This review discusses the etiology of autoimmune diseases, current therapeutic approaches, and prospects for future drug design. Full article

Yolkin, an egg yolk immunoregulatory protein, stimulates the humoral but inhibits the cellular immune response in adult mice. The aim of this investigation was to evaluate the effects of yolkin administration on the immune response using a model of juvenile, i.e., 28-day- and 37-day-old, mice. We examined the yolkin influence on the magnitude of the cellular immune response, which was determined as contact sensitivity (CS) to oxazolone (OXA), and the humoral immune response, which was determined as the antibody response to ovalbumin (OVA). Yolkin was administered in drinking water, followed by immunization with OXA or OVA. In parallel, the phenotypic changes in the lymphoid organs were determined following yolkin treatment and prior immunization. The results showed that yolkin had a stimulatory effect on CS in the mice treated with yolkin from the 37th day of life but not from the 28th day of life. In contrast, no regulatory effect of yolkin on antibody production was found in 28-day- and 37-day-old mice. Phenotypic studies revealed significant changes in the content of B cells and T cell subpopulations, including CD4+CD25+Foxp3 regulatory T cells. The association between the effects of yolkin on the magnitude of CS and phenotypic changes in main T- and B-cell compartments, as well the importance of changes in T-regulatory and CD8+ cells in the age categories, are discussed. We conclude that the immunoregulatory effects of yolkin on the generation of CS in mice are age dependent and change from stimulation in juvenile to suppression in adult mice. Full article

Human immunodeficiency virus (HIV) infection remains an important global public health problem. About 40 million people are infected with HIV, and this infection caused about 630,000 deaths in 2022. The hallmark of HIV infection is the depletion of CD4+ T helper lymphocytes (Th cells). There are at least seven different Th subtypes, and not all are the main targets of HIV. Moreover, the effect of the virus in a specific subtype can be completely different from that of the others. Although the most compromised Th subtype in HIV infection is Th17, HIV can induce important dysregulations in other subtypes, such as follicular Th (Tfh) cells and regulatory Th cells (Treg cells or Tregs). Several studies have shown that HIV can induce an increase in the immunosuppressive activity of Tregs without causing a significant reduction in their numbers, at least in the early phase of infection. The increased activity of this Th subtype seems to play an important role in determining the immunodeficiency status of HIV-infected patients, and Tregs may represent a new target for innovative anti-HIV therapies, including the so-called “Kick and Kill” therapeutic method whose goal is the complete elimination of the virus and the healing of HIV infection. In this review, we report the most important findings on the effects of HIV on different CD4+ T cell subtypes, the molecular mechanisms by which the virus impairs the functions of these cells, and the implications for new anti-HIV therapeutic strategies. Full article