Increase In Treg Cells Research Articles

Differential Control of T-Cell Subsets by Recombinant Human PLD2 in a Mouse Model of Allergic Asthma

ABSTRACT Background Phospholipase D2 (PLD2) enzymes are expressed on the cytoplasmic membrane of bacteria, fungi, plants, and animals. Recently, extensive research has linked PLD2 to the chronic inflammatory activity of cells. Allergic asthma is a chronic airway inflammation disease. In this context, a recombinant human phospholipase D2 (rhPLD2) was designed and modified from the wild-type PLD2 to study its effects in an ovalbumin (OVA) induced murine model of asthma. Methods Hematoxylin and eosin staining was used for lung histopathology. Cytokine concentrations in bronchoalveolar lavage fluid (BALF) were measured using ELISA kits. The ratio of T-bet and GATA-3 expression level in spleen and lymph nodes following rhPLD2 administration was assessed through RT-PCR. Phenotyping analysis of Treg cells from peripheral blood was performed by flow cytometry. Results It indicated that OVA-induced mice exhibited elevated pulmonary eosinophilia and allergic inflammation in the airways, along with increased expression of IFN-γ, IL-4 in the lung BALF. Administration of rhPLD2 alleviated lung inflammation and significantly reduce the number of eosinophils in peripheral blood and BALF. RhPLD2 also reversed the IFN-γ/IL-4 ratio at the molecular level in BALF and the T-bet/GATA-3 ratio in lymphocytes of the lung, spleen, lymph nodes at the genetic level. Furthermore, FACS analysis demonstrated that rhPLD2 increased the frequency of both IL-10+Treg cells and CD25+ Treg cells. Conclusion From a therapeutic perspective, rhPLD2 alleviates allergic airway inflammation by balancing Th1/Th2 homeostasis and increasing Treg cells. It has been shown to function in immunoregulatory activities in OVA-induced asthma mice.

Macrophages promote pre-metastatic niche formation of breast cancer through aryl hydrocarbon receptor activity

Macrophages that acquire an immunosuppressive phenotype play a crucial role in establishing the pre-metastatic niche (PMN), which is essential for facilitating breast cancer metastasis to distant organs. Our study showed that increased activity of the aryl hydrocarbon receptor (AHR) in lung macrophages plays a crucial role in establishing the immunosuppressive PMN in breast cancer. Specifically, AHR activation led to high expression of PD-L1 on macrophages by directly binding to the promoter of Pdl1. This upregulation of PD-L1 promoted the differentiation of regulatory T cells (Tregs) within the PMN, further enhancing immunosuppressive conditions. Mice with Ahr conditional deletion in macrophages had reduced lung metastasis of breast cancer. The elevated AHR levels in PMN macrophages were induced by GM-CSF, which was secreted by breast cancer cells. Mechanistically, the activated STAT5 signaling pathway induced by GM-CSF prevented AHR from being ubiquitinated, thereby sustaining its activity in macrophages. In breast cancer patients, the expression of AHR and PD-L1 was correlated with increased Treg cell infiltration, and higher levels of AHR were associated with a poor prognosis. These findings reveal that the crosstalk of breast cancer cells, lung macrophages, and Treg cells via the GM-CSF-STAT5-AHR-PD-L1 cascade modulates the lung pre-metastatic niche during breast cancer progression.

Ketogenic diet modulates immune cell transcriptional landscape and ameliorates experimental autoimmune uveitis in mice

BackgroundUveitis manifests as immune-mediated inflammatory disorders within the eye, posing a serious threat to vision. The ketogenic diet (KD) has emerged as a promising dietary intervention, yet its impact on the immune microenvironments and role in uveitis remains unclear.MethodsUtilizing single-cell RNA sequencing (scRNA-seq) data from lymph node and retina of mice, we conduct a comprehensive investigation into the effects of KD on immune microenvironments. Flow cytometry is conducted to verify the potential mechanisms.ResultsThis study demonstrates that KD alters the composition and function of immune profiles. Specifically, KD promotes the differentiation of Treg cells and elevates its proportion in heathy mice. In response to experimental autoimmune uveitis challenges, KD alleviates the inflammatory symptoms, lowers CD4+ T cell pathogenicity, and corrects the Th17/Treg imbalance. Additionally, KD decreases the proportion of Th17 cell and increases Treg cells in the retina. Analysis of combined retinal and CDLN immune cells reveals that retinal immune cells, particularly CD4+ T cells, exhibit heightened inflammatory responses, which KD partially reverses.ConclusionsThe KD induces inhibitory structural and functional alterations in immune cells from lymph nodes to retina, suggesting its potential as a therapy for uveitis.

Feedback regulation of VISTA and Treg by TNF-α controls T cell responses in drug allergy.

Severe cutaneous adverse reactions (SCARs) mediated by cytotoxic T lymphocytes are a series of life-threatening conditions with a mortality of 4%-20%. The clinical application of tumor necrosis factor-alpha (TNF-α) antagonist improves the outcome of some SCARs patients; however, this is complicated by the elusive and varied immunopathogenesis. To investigate whether IgE antibody responses to HEMAs are associated with AD, its severity, and response to dupilumab. To clarify the precise process and optimize the therapy regimen of SCARs, we performed single-cell sequencing, invitro functional and clinical analysis of patients with SCARs. We observed that TNF-α breaks drug-specific T-cell tolerance by inhibiting the expression of V-type immunoglobulin domain-containing suppressor of T-cell activation (VISTA). Furthermore, TNF-α generated a positive feedback loop in the early phase of drug-specific T-cell activation, whereby B cells acted reciprocally on the corresponding T cells to reinforce TNF-α cytokine expression. In contrast, this pathway of TNF-α-VISTA signaling did not operate in memory effector T cells. Drug-specific memory effector T-cell responses were inhibited by increasing Treg cell expression in a negative feedback loop, with TNF-α antagonists preventing the inhibitory effect. These observations align with the clinical analysis that early but not late intervention with TNF-α antagonists significantly improved outcomes in SCARs patients. Our findings defining feedback regulation of VISTA and Treg cells by TNF-α in different stages of the drug-specific T-cell response and, indicate that a Treg agonists, instead of TNF-α antagonists, could be used for treatment of patients with progressive SCARs.

Dihydroberberine alleviates Th17/Treg imbalance in premature ovarian insufficiency mice via inhibiting Rheb/mTOR signaling

BackgroundPremature ovarian insufficiency (POI) is an immune-related condition. Dihydroberberine (dhBBR) plays a regulatory role in maintaining the T-helper 17 (Th17)/regulatory T (Treg) cell balance. This study aimed to explore the action mechanisms of dhBBR on POI.MethodsIn vivo, female BALB/c mice were used as POI models, treated with dhBBR, or injected with recombinant interleukin (rIL)-17 and anti-CD25 monoclonal antibody. Hematoxylin and eosin staining was used to validate the model and assess the therapeutic effects of dhBBR. mRNA expression levels of cytochrome P450 (Cyp)-17a1, Cyp19a1, Cyp11a1, steroidogenic acute regulatory protein, and luteinizing hormone receptor in mouse ovaries were quantified via quantitative polymerase chain reaction (qPCR). Enzyme-linked immunosorbent assay was used to determine the cytokine and sex hormone levels. Immunohistochemical staining for cleaved-caspase 3 and Ki-67 were performed to assess ovarian cell apoptosis and proliferation. Flow cytometry was used to analyze the Th17/Treg cell balance in the ovary and spleen. In vitro cytotoxicity of dhBBR was measured using the cell counting kit-8 assay. GTP-Ras homolog enriched in brain (Rheb) activity was determined via immunofluorescence assay. Co-immunoprecipitation was performed to assess Rheb activity, Th17 or Treg induction, and binding between Rheb and mammalian target of rapamycin (mTOR) after dhBBR treatment. Flow cytometry and qPCR assays were used to verify the effect of dhBBR on CD4 + cell differentiation. Finally, Rheb/mTOR pathway activation was confirmed via western blotting of proteins, including mTOR, p-mTOR, p70S6K, p-p70S6K, 4E-BP1, and p-4E-BP1.ResultsdhBBR improved the ovarian function in a dose-dependent manner. It also decreased ovarian cell apoptosis and increased cell proliferation. It decreased Th1 and Th17 cell proportions but increased Treg cell proportions in the ovaries and spleens of POI model mice. Cell experiments revealed that dhBBR promoted CD4 + cell differentiation into Treg cells. Co-immunoprecipitation revealed Rheb as the dhBBR target that bound to mTOR. However, MHY1485 restored dhBBR-induced changes in forkhead box P3, IL-10, transforming growth factor-β1, IL-17, IL-22, retinoic acid-related orphan receptor-γt and p-mTOR levels in Th17- and Treg-induced CD4 + cells.ConclusionOverall, dhBBR targeted the Rheb/mTOR pathway to promote CD4 + cell differentiation into Treg cells and alleviate POI.

Interleukin-2 improves insulin sensitivity through hypothalamic sympathetic activation in obese mice

BackgroundIL-2 regulates T cell differentiation: low-dose IL-2 induces immunoregulatory Treg differentiation, while high-dose IL-2 acts as a potent activator of cytotoxic T cells and NK cells. Therefore, high-dose IL-2 has been studied for use in cancer immunotherapy. We aimed to utilize low-dose IL-2 to treat inflammatory diseases such as obesity and insulin resistance, which involve low-grade chronic inflammation.Main bodySystemic administration of low-dose IL-2 increased Treg cells and decreased inflammation in gonadal white adipose tissue (gWAT), leading to improved insulin sensitivity in high-fat diet-fed obese mice. Additionally, central administration of IL-2 significantly enhanced insulin sensitivity through the activation of the sympathetic nervous system. The sympathetic signaling induced by central IL-2 administration not only decreased interferon γ (IFNγ) + Th1 cells and the expression of pro-inflammatory cytokines, including Il-1β, Il-6, and Il-8, but also increased CD4 + CD25 + FoxP3 + Treg cells and Tgfβ expression in the gWAT of obese mice. These phenomena were accompanied by hypothalamic microgliosis and activation of pro-opiomelanocortin neurons. Furthermore, sympathetic denervation in gWAT reversed the enhanced insulin sensitivity and immune cell polarization induced by central IL-2 administration.ConclusionOverall, we demonstrated that IL-2 improves insulin sensitivity through two mechanisms: direct action on CD4 + T cells and via the neuro-immune axis triggered by hypothalamic microgliosis.

Retinoic Acid (RA): A Critical Immunoregulatory Molecule in Asthma and Allergies.

Asthma and allergies are chronic inflammatory disorders that are triggered owing to aberrant responses of the immune system against typically innocent environmental substances. Retinoic acid (RA) represents a biologically active metabolite of vitamin A (VA) and high-affinity ligand for RA receptor (RAR) that is implicated in a wide variety of biological processes, including cell proliferation, differentiation, apoptosis, organogenesis, reproduction, and immune responses. In the immune system, RA contributes to the induction of regulatory T (Treg) cells, adhesion molecules required for homing of B and T cells in the gut, and tolerance. Noteworthy, RA has a pivotal role in maintaining the balance of Th17-Treg cells and is also indispensable for appropriate responses of T helper (Th) cells. This mini-review article intends to expose the immune functions of RA, with an emphasis on the enzymatic pathways converting VA into RA and its receptor-dependent actions in asthma and allergies. Recent findings have depicted that RA levels are reduced in asthma and allergies and that treatment with RA alleviates allergy symptoms and airway inflammation. RA also modulates allergic airway disorders by inhibiting Th2/Th17 response and increasing Treg cells. Therefore, RA could be considered a novel and promising therapeutic agent to be studied and used for treating these diseases.

Bone marrow mesenchymal stem cells-derived exosomal miR-381 alleviates lung ischemia-reperfusion injury by activating Treg differentiation through inhibiting YTHDF1 expression

AimOur study aimed to investigate whether BMSCs-derived exosomal miR-381 promotes Treg cell differentiation in lung ischemia-reperfusion injury (LIRI), and the underlying mechanism. MethodsThe in vitro and in vivo models of LIRI were established by hypoxia/reoxygenation (H/R) treatment and lung ischemia/reperfusion (I/R) surgery, respectively. BMSCs-derived exosomes were isolated and identified by western blot, nanoparticle tracking analysis, and transmission electron microscopy. Cell viability, proliferation, and apoptosis were assessed by CCK-8, EdU, and flow cytometry assay, respectively. IL-18 secretion level in lung microvascular endothelial cells (LMECs) and lung tissue homogenate was examined by ELISA. Treg cell differentiation was determined using flow cytometry. The relationships between miR-381, YTHDF1, and IL-18 were investigated using dual-luciferase reporter gene, RIP, and/or RNA pull-down assays. MeRIP assay was employed to determine m6A modification of IL-18 mRNA in LMECs. The ubiquitination level of Foxp3 protein in CD4+ T cells was analyzed by Co-IP assay. ResultsBMSCs-derived exosomes reduced LMECs injury and increased Treg cell differentiation in LIRI, whereas miR-381 inhibition in BMSCs weakened these impacts. Mechanistically, miR-381 inhibited IL-18 translation in LMECs by inhibiting YTHDF1 expression via binding to its 3’-UTR. As expected, YTHDF1 overexpression in LMECs abolished the effects of miR-381-overexpressed exosomes on LMECs injury and Treg cell differentiation. Moreover, LMECs-secreted IL-18 inhibited Treg cell differentiation by promoting the ubiquitination degradation of Foxp3 protein. ConclusionBMSCs-derived exosomal miR-381 suppressed IL-18 translation in LMECs through binding to YTHDF1 3’-UTR, thus suppressing the ubiquitination degradation of Foxp3 in CD4+ T cells, which promoted Treg cell differentiation and mitigated LIRI development.

The use of metagenomic and untargeted metabolomics in the analysis of the effects of the Lycium barbarum glycopeptide on allergic airway inflammation induced by Artemesia annua pollen

Ethnopharmacological relevanceThe prevalence of allergic airway inflammation (AAI) worldwide is high. Artemisia annua L. pollen is spread worldwide, and allergic diseases caused by its plant polysaccharides, which are closely related to the intestinal microbiota, have anti-inflammatory effects. Further isolation and purification of Lycium barbarum L. yielded its most effective component Lycium barbarum L. glycopeptide (LbGP), which can inhibit inflammation in animal models. However, its therapeutic effect on AAI and its mechanism of regulating the intestinal flora have not been fully investigated. Aim of the studyTo explore LbGP in APE-induced immunological mechanisms of AAI and the interaction mechanism of the intestinal flora and metabolites. MethodsA mouse model of AAI generated from Artemisia annua pollen was constructed, and immunological indices related to the disease were examined. A combination of macrogenomic and metabolomic analyses was used to investigate the effects of LbGP on the gut microbial and metabolite profiles of mice with airway inflammation. ResultsLbGP effectively alleviated Artemisia. annua pollen extract (APE)-induced AAI, corrected Th1/Th2 immune dysregulation, decreased Th17 cells, increased Treg cells, and altered the composition and function of the intestinal microbiota. LbGP treatment increased the number of OdoribacterandDuncaniella in the intestines of the mice, but the numble of Alistipes and Ruminococcus decreased. Metabolite pathway enrichment analysis were used to determine the effects of taurine and hypotaurine metabolism, bile acid secretion, and pyrimidine metabolism pathways on disease. ConclusionOur results revealed significant changes in the macrogenome and metabolome following APE and LbGP intervention, revealed potential correlations between gut microbial species and metabolites, and highlighted the beneficial effects of LbGP on AAI through the modulation of the gut microbiome and host metabolism.

Genomic and immune heterogeneity of multiple synchronous lung adenocarcinoma at different developmental stages

Multiple synchronous lung cancers (MSLCs) constitute a unique subtype of lung cancer. To explore the genomic and immune heterogeneity across different pathological stages of MSLCs, we analyse 16 MSLCs from 8 patients using single-cell RNA-seq, single-cell TCR sequencing, and bulk whole-exome sequencing. Our investigation indicates clonally independent tumours with convergent evolution driven by shared driver mutations. However, tumours from the same individual exhibit few shared mutations, indicating independent origins. During the transition from pre-invasive to invasive adenocarcinoma, we observe a shift in T cell phenotypes characterized by increased Treg cells and exhausted CD8+ T cells, accompanied by diminished cytotoxicity. Additionally, invasive adenocarcinomas exhibit greater neoantigen abundance and a more diverse TCR repertoire, indicating heightened heterogeneity. In summary, despite having a common genetic background and environmental exposure, our study emphasizes the individuality of MSLCs at different stages, highlighting their unique genomic and immune characteristics.

Microbiota alert: Proteobacteria consume arginine to dampen omental antitumor immunity

The microbiota can impact antitumor immunity, but whether the microbiota regulates omental antitumor immunity remains elusive. In this issue of Cell Host & Microbe, Meza-Perez etal. demonstrated that Proteobacteria consume arginine to increase Treg cell suppressive capacity and inhibit antitumor immune responses, promoting tumor growth in the omentum.

Elevated Serum Tumor Markers (HE4 and ROMA Score) and Increased Treg Cells Distinguished Ovarian Cancer and Benign Tumor

BACKGROUND: Tumor markers such as human epididymis protein 4 (HE4), cancer antigen 125 (CA-125), and risk of ovarian malignancy algorithm (ROMA) are frequently utilized for diagnostic and prognostic purposes. Lymphocytes, essential immune cells, play a significant role in eliminating cancer cells. However, the precise correlation between tumor markers and lymphocytes remains incompletely elucidated. The aim of this study was to explore the correlation between tumor markers and lymphocyte subtype profiles in differentiating ovarian cancer and benign tumors.METHODS: This was a cross-sectional study involving 12 ovarian cancer and 17 benign ovarian tumor patients. Blood samples were collected for the characterization of T lymphocytes, B lymphocytes, natural killer (NK), and T regulatory (Treg), which were analyzed using flowcytometry. Additionally, tumor markers HE4 and CA-125 were measured from patient serum using the chemiluminescent microparticle immunoassay (CMIA) method.RESULTS: Benign ovarian tumors and ovarian cancer can be distinguished by a significant increase in HE4 levels (p=0.004), ROMA (p=0.004), and Treg cells (CD4+/CD25+/FOXP3+, p=0.017). Furthermore, the correlation between tumor markers and lymphocytes indicates that an increase in ROMA was weakly correlated with an increase in the percentage of T regulatory cells (CD4+/CD25+/FOXP3+, r=0.553, p=0.006) and B lymphocytes (CD19+, r=0.528, p=0.010), accompanied by a decrease in the number of T lymphocytes (CD3+, r=-0.598, p=0.003), T helper lymphocytes (CD3+CD4+, r=-0.594, p=0.003), and cytotoxic lymphocytes (CD3+CD8+, r=-0.510, p=0.013).CONCLUSION: The elevation of serum tumor markers (HE4 and ROMA) accompanied by an increase in Treg cells can distinguish between benign ovarian tumor patients and ovarian cancer patients.KEYWORDS: tumor marker, CA-125, HE4, ROMA, subtype of lymphocytes, ovarian cancer

Low-intensity pulsed ultrasound protects from inflammatory dilated cardiomyopathy through inciting extracellular vesicles.

CD4+ T cells are activated during inflammatory dilated cardiomyopathy (iDCM) development to induce immunogenic responses that damage the myocardium. Low-intensity pulsed ultrasound (LIPUS), a novel physiotherapy for cardiovascular diseases, has recently been shown to modulate inflammatory responses. However, its efficacy in iDCM remains unknown. Here, we investigated whether LIPUS could improve the severity of iDCM by orchestrating immune responses and explored its therapeutic mechanisms. In iDCM mice, LIPUS treatment reduced cardiac remodelling and dysfunction. Additionally, CD4+ T-cell inflammatory responses were suppressed. LIPUS increased Treg cells while decreasing Th17 cells. LIPUS mechanically stimulates endothelial cells, resulting in increased secretion of extracellular vesicles (EVs), which are taken up by CD4+ T cells and alter their differentiation and metabolic patterns. Moreover, EVs selectively loaded with microRNA (miR)-99a are responsible for the therapeutic effects of LIPUS. The hnRNPA2B1 translocation from the nucleus to the cytoplasm and binding to caveolin-1 and miR-99a confirmed the upstream mechanism of miR-99a transport. This complex is loaded into EVs and taken up by CD4+ T cells, which further suppress mTOR and TRIB2 expression to modulate cellular differentiation. Our findings revealed that LIPUS uses an EVs-dependent molecular mechanism to protect against iDCM progression. Therefore, LIPUS is a promising new treatment option for iDCM.

Clinical study reveals the efficacy of sirolimus in treating primary immune thrombocytopenia: findings from a single-center study.

Immune thrombocytopenia (ITP) is an autoimmune disease that arises because of self-destruction of circulating platelets. The mechanism remains complicated and lacks a standard clinical treatment. Current first-line and second-line medications for ITP have shown limited effectiveness, necessitating the exploration of new therapeutic options. Sirolimus is a mammalian target of rapamycin (mTOR) inhibitor that has been demonstrated to inhibit lymphocyte activity, indicating potential for SRL in the treatment of ITP. This study aimed to evaluate the clinical efficacy of sirolimus as a second-line drug in patients with ITP. The starting dose of sirolimus for adults ranged from 2 to 4 mg/day, with a maintenance dose of 1 to 2 mg/day. For children, the starting dose was 1-2 mg/day, with a maintenance dose of 0.5-1 mg/day. The dosage could be adjusted if needed to maintain a specific blood concentration of sirolimus, typically between 5 and 15 ng/ml, throughout the treatment period. After 3 months, the overall response rate was 60% (12/20), with 30% of patients (6/20) achieving a complete response (CR) and 30% (6/20) achieving a partial response (PR). The CR rate at 6 months remained consistent with the 3-month assessment. No major adverse events were reported, indicating that sirolimus was well tolerated and safe. Analysis of peripheral blood Treg cell percentages in both the control and ITP showed no significant difference before treatment. The percentage of Treg cells increased after treatment with sirolimus, suggesting that sirolimus increases Treg cells. These findings suggest that sirolimus serves as an effective second-line treatment option for ITP, demonstrating favorable clinical efficacy.

Abstract CT263: Atezolizumab clinical trial biopsies reveal varied immune landscapes in clear cell sarcoma and chondrosarcoma

Abstract Introduction: Clear cell sarcoma (CCS) constitutes <1% of sarcomas and frequently presents in adolescents and young adults. Chondrosarcoma is one of the most common bone malignancies in adults, occurring as conventional chondrosarcoma (CS) or the more-aggressive dedifferentiated chondrosarcoma (dCS). There is no standard of care therapy approved for these malignancies. The activity of immune checkpoint inhibition (ICI) in alveolar soft part sarcoma, together with case reports of ICI activity in these other sarcoma subtypes, prompted us to conduct a phase 2 clinical trial of atezolizumab (atezo), in patients (pts) with advanced CCS, CS, or dCS (NCT04458922). Methods: We evaluated the effect of targeting PD-L1 with atezo upon the growth and immune landscape of CCS, CS, and dCS. Pts received intravenous atezo 1200 mg/m2 once every 21 days. Prior ICI therapy was not allowed. Tumor biopsy pairs for immuno-pharmacodynamic (IO-PD) studies were collected at baseline and on Cycle 3 Day 1(C3D1); paraffin sections were analyzed using immunofluorescence (IF) microscopy after staining with two multiplexed antibody panels (CD4/FOXP3 and PD-L1/CD8/CD3ζ pY142). Biomarker-positive cells within the tumor area and margins were quantified using image analysis algorithms. Activated cytotoxic T lymphocytes (CTLs) were defined as CD8+ CD3ζ pY142+ and reported as the percentage of the total CD8+ cell density. Results: Nine pts were enrolled per disease cohort. No RECIST objective responses were observed; accrual was closed due to futility. Median progression-free survival (PFS) was 2.66 months (range: 1.3 to 11.7) in CCS, 3.22 (range: 1.4 to 8.9) in CS, and 2.04 (range: 0.4 to 11.7) in dCS. IF microscopy of biopsy pairs from five CCS pts revealed varied immune landscapes: 4/5 C3D1 biopsies contained PD-L1+ cells, 4/5 contained CD8+ cells, and 3/5 contained activated CTLs. Immune phenotype did not generally correlate with response; however, the highest percentage of activated CTLs occurred in the CCS pt with the longest PFS and this pt showed an increase in PD-L1+ cells on treatment—consistent with target engagement of the PD-L1/PD-1 immune checkpoint. dCS biopsy pairs (N=3) also contained a range of biomarker densities that did not correlated with PFS. In dCS and CCS, on-treatment increases in the percentage of activated CTLs were accompanied by increased Treg cell density in some pts. In contrast, CS biopsies (N=5) were uniformly devoid of infiltrating immune cells. Conclusion: The tumor microenvironment of CS is an immune desert, while dCS and CCS tumors contain a range of immune cell compositions. Atezo treatment increased the percentage of activated CTLs and density of PD-L1+ cells in some tumors, but an increase in Treg cells may explain why that pharmacodynamic evidence of ICI activity (the increase in activated CTLs) was not associated with clinical response. Funded NCI Contract No. HHSN261201500003I. Citation Format: Katherine V. Ferry-Galow, Kristin K. Fino, Geraldine O'Sullivan Coyne, Nancy Moore, Elad Sharon, Melissa Burgess, James Chen, Anthony P. Conley, Elizabeth J. Davis, Priscilla Merriam, Albiruni R. Abdul Razak, Brian Van Tine, Jared C. Foster, Naoko Takebe, Christina L. Rosenberger, James H. Doroshow, Alice P. Chen, Ralph E. Parchment. Atezolizumab clinical trial biopsies reveal varied immune landscapes in clear cell sarcoma and chondrosarcoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT263.

Assessing the effectiveness of Interleukin-2 therapy in experimental type 1 diabetes

AimMuch focus of immunotherapy for type 1 diabetes (T1D) has been devoted on selectively boosting regulatory T (Treg) cells using low dose IL-2 due to their constitutive expression of IL-2Rα, CD25. However, several clinical trials using a low dose of IL-2 only showed a limited improvement of metabolic control. It can therefore be hypothesized that further decreasing IL-2 dosage may increase the selective responsiveness of Treg cells.MethodsWe induced experimental T1D using multiple low dose streptozotocin (STZ) injections and treated the mice with an ultra-low dose IL-2 (uIL-2, approximately 7-fold lower than low dose). Immune response was studied using multicolor flow cytometry.ResultsWe found that uIL-2 did not protect STZ mice from developing hyperglycemia. It did neither increase Treg cell proportions, nor did it correct the phenotypic shift of Treg cells seen in T1D. It only partially decreased the proportion of IFN-γ+ T cells. Likewise, uIL-2 also did not protect the dysfunction of regulatory B (Breg) cells. Strikingly, when administered in combination with an anti-inflammatory cytokine IL-35, uIL-2 abrogated IL-35’s protective effect. Low dose IL-2, on the other hand, protected half of the STZ mice from developing hyperglycemia. No difference was found in the Treg and Breg response, and it only tended to decrease CD80 expression in macrophages and dendritic cells.ConclusionIn conclusion, further decreasing IL-2 dosage may not be a suitable approach for T1D therapy, and the limited success suggests that an alternative low dose IL-2 therapy strategy or other immunotherapies should be considered.

Turmeric: A Spice Modulating Immune Response and Combatting Cancer – literature overview

Introduction Curcumin, the active ingredient in turmeric, is gaining increasing attention due to its potential health benefits, especially in the context of its immunomodulatory and anticancer properties. Aim of the study The aim of this review was to discuss recent findings regarding the impact of curcumin on the immune system and its potential applications in anticancer therapy. Materials and methods The paper was created based on the Pubmed and Scholar database. The literature was reviewed using the keywords: „curcumin”, „immunomodulatory effects”, „cytokines”, „anticancer”, „apoptosis”, „cell proliferation”, „radiosensitizing”. Results Studies have confirmed that curcumin, especially in the form of nanocurcumin, exhibits significant immunomodulatory effects. It reduces the number of Th17 cells, increases Treg cells, and regulates the expression of pro-inflammatory cytokines, which is crucial in controlling autoimmune reactions. Furthermore, it demonstrates anticancer activity by inhibiting the growth of cancer cells, stimulating apoptosis, and enhancing the effectiveness of anticancer therapy. Conclusions Despite promising results, further research on the safety of curcumin therapy, particularly in the long term, is essential. Limitations associated with bioavailability and pharmacokinetics suggest the need for the development of formulations with increased bioavailability to maximize the potential benefits of curcumin in the treatment of various disorders.

Mechanism of Late Recurrences of Chronic Myeloid Leukemia after Discontinuation of TKI Therapy: BCR::ABL1 Ins35bp Loss-of-Function Splicing Mutation and Regulatory T Cells

Introduction: Treatment-free remission (TFR) as one of the goals of treatment of BCR::ABL-positive chronic phase chronic myeloid leukemia (CML) has been proposed. Actually, approximately 40-60% of CML patients maintain TFR without recurrence after discontinuation of tyrosine kinase inhibitors (TKIs). In some of such patients, there are fluctuated cases in which BCR::ABL positive clones continue to be detected for long periods at levels of international scale (IS) BCR::ABL < 0.1%. Such fluctuated cases show no apparent molecular recurrence and maintain TFR for a long time, but they have also been shown to be more likely to eventually develop late recurrence (Haematologica 2022, Blood adv. 2020). We have reported that a higher percentage of PD-1 positive CD8 + T cells before and after TKI discontinuation is associated with molecular recurrence, and together with the possibility of assessing host immune response capacity after TKI discontinuation by using regulatory T (Treg) cells (Fujioka, et al. Cancers 2021). On the other hands, mutations in BCR::ABL caused by the alternative splicing, such as BCR::ABL Ins35bp, are known to be one of the TKI resistance in CML. Loss of BCR::ABL kinase activity is thought to result in loss of TKI sensitivity and thus failure to achieve deep molecular remission (Yuda, et al. Cancer Science 2017). In this study, we analyzed the mutations that cause splicing variants such as BCR::ABL Ins35bp and host immune response in CML patients to elucidate molecular mechanisms in the long-term maintenance of TFR and late recurrence. Methods: Twenty-four CML patients who discontinued TKI treatment for any reason at Akita University Hospital were included in the study. The trends of IS level after TKI discontinuation were monitored, and immune profile analysis by multi-color flow cytometry (FCM) was performed in all patients. Mutation analysis of the BCR::ABL region including splicing variants was performed in selected patients. Mutation analysis was performed on samples with sufficient cell count and IS > 0.0032% (MR 4.5), and the BCR::ABL region of these samples was amplified by long nested PCR and then analyzed by the next-generation sequencer (NGS). Results: First, BCR::ABL Ins35bp was evaluated by mutation analysis. Among CML patients who underwent mutation analysis, BCR::ABL Ins35bp was detected in all cases in which the samples could perform analysis at newly diagnosis (ND). Even after TKI discontinuation, a certain percentage of BCR::ABL Ins35bp was detected in all patients, and the percentage of BCR::ABL Ins35bp increased at the time of recurrence regardless of whether early or late. These results suggest that function-dead BCR::ABL Ins35bp clones may remain in CML patients with detectable BCR::ABL under and after TKI treatment, and eventually leading to recurrence with transcriptional promotion of native BCR::ABL. On the other hand, there were cases in which the BCR::ABL Ins35bp was lost at the time of recurrence. There is a possibility of immunological involvement in such cases. CML patients with detectable BCR::ABL in the TFR for a long time had a decreased immunosuppressive Treg cells, while analysis using late recurrence increased Treg cells prior to recurrence (figure). These suggest the presence of cases in which early recurrence is suppressed by host immune responses. Conclusion: Although the loss of function mutations such as BCR::ABL Ins35bp was previously thought to occur after TKI administration as a cause of TKI resistance, this analysis reveals that the clone is included from the ND before TKI treatment. Examining the BCR::ABL Ins35bp clone at ND may be possible to predict the possibility of recurrence after TFR. Host immune capacity, as assessed by the kinetics of Treg after TKI discontinuation, may contribute to prolonged TFR. Thus Treg monitoring may be important in predicting molecular recurrence, especially in BCR::ABL Ins35bp cases.

Immune tolerance induced in the anterior chamber ameliorates corneal transplant rejection

The relevance of regulatory T cells (Tregs) in induction of tolerance against corneal allografts has been well established. However, whether Tregs can be induced in the anterior chamber and suppress local alloimmune response after corneal transplantation is largely unknown. In the current study we report that not only can alloantigen specific Tregs be generated in the anterior chamber during corneal transplantation, they also play important roles in suppressing allograft rejection. Allograft rejected mice exhibit reduced Treg induction in the anterior chamber and the ability of aqueous humor and corneal endothelial cells from allograft rejected mice to induce Tregs is compromised. Further analysis revealed that the expression of immune-tolerance-related molecules is significantly decreased. Finally, we demonstrate that increasing Treg cells specifically in the anterior chamber can effectively suppress allograft rejection and exhibits better efficacy in promoting corneal allograft survival than systemic administration of Treg cells. Our current study may provide new ideas for the prevention and treatment of corneal transplant rejection.

Alleviating psoriatic skin inflammation through augmentation of Treg cells via CTLA-4 signaling peptide.

Psoriasis is a chronic inflammatory skin disease characterized by hyperplasia of keratinocytes and immune cell infiltration. The IL-17-producing T cells play a key role in psoriasis pathogenesis, while regulatory T (Treg) cells are diminished during psoriatic inflammation. Current psoriasis treatments largely focus on IL-17 and IL-23, however, few studies have explored therapeutic drugs targeting an increase of Treg cells to control immune homeostasis. In this study, we investigated the effects of a cytotoxic T lymphocyte antigen-4 (CTLA-4) signaling peptide (dNP2-ctCTLA-4) in Th17, Tc17, γδ T cells, Treg cells in vitro and a mouse model of psoriasis. Treatment with dNP2-ctCTLA-4 peptide showed a significant reduction of psoriatic skin inflammation with increased Treg cell proportion and reduced IL-17 production by T cells, indicating a potential role in modulating psoriatic skin disease. We compared dNP2-ctCTLA-4 with CTLA-4-Ig and found that only dNP2-ctCTLA-4 ameliorated the psoriasis progression, with increased Treg cells and inhibited IL-17 production from γδ T cells. In vitro experiments using a T cell-antigen presenting cell co-culture system demonstrated the distinct mechanisms of dNP2-ctCTLA-4 compared to CTLA-4-Ig in the induction of Treg cells. These findings highlight the therapeutic potential of dNP2-ctCTLA-4 peptide in psoriasis by augmenting Treg/Teff ratio, offering a new approach to modulating the disease.