Search

Ezrin is a cross-linker protein between membrane proteins and cytosolic actin, abundantly expressed in the placenta among the ERM protein family. Ezrin gene knockout mice exhibit fetal growth restriction after gestational day (GD) 15.5. This study aimed to clarify the effect of ezrin on immune cells that influence fetal growth and immune tolerance. Ezrin heterozygous knockout (Ez +/- ) mice were interbred, and the gene expressions and immune cell distributions in the placentas of wild-type (Ez +/+ ) and ezrin knockout (Ez -/- ) fetuses were analyzed. IL-6 expression in the placenta of Ez -/- fetuses was significantly higher than in Ez +/+ fetuses at GD 15.5. The mRNA expression of IL-6 in the uterine decidua attached to Ez -/- fetuses was higher compared to that attached to Ez +/+ fetuses but not in the junctional zone and labyrinth. Classical M1 and M2 macrophages in the decidua were analyzed by flow cytometry using CD86 and CD206 as markers. M1 macrophages increased in the decidua attached to Ez -/- mice compared to Ez +/+ mice, while M2 macrophages did not increase. CD4-positive T cells showed a reduction in the decidua attached to Ez -/- fetuses. Further analysis involved the subcutaneous administration of tacrolimus in pregnant Ez +/- mice from GD 8.5 to GD 15.5, which prevented the decrease in fetal body weight and decidual CD4-positive T cells in Ez -/- mice at GD 15.5. These results suggest that impaired expression of fetoplacental-derived ezrin induces inflammatory conditions in the uterine decidua through M1 polarization of macrophages, increased IL-6, and decreased CD4-positive T cells, including Treg cells., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Tomohiro Nishimura reports financial support was provided by Japan Society for the Promotion of Science and by Mochida Memorial Foundation for Medical and Pharmaceutical Research. Masatoshi Tomi reports financial support was provided by AMED−CREST, AMED and by Hoansha Foundation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Autoimmune diseases are broadly characterized as a failure in immune tolerance. In multiple sclerosis (MS), autoreactive immune cells attack the protective myelin sheath lining neurons in the central nervous system. Therapeutic strategies that selectively and durably restore immune tolerance without broad immunosuppression are urgently needed for MS. Our lab has developed assemblies of immune constructs built entirely from myelin antigen (MOG 35-55 or PLP 139-151 ) and regulatory innate immune cues (GpG) using layer-by-layer self-assembly. Here, we present mechanistic and translational data showing these assemblies confer therapeutic benefits in a range of clinically relevant disease contexts, including progressive disease in male mice and in relapsing-remitting disease that mimics the intermittent bouts of disease and remission most MS patients initially experience. Here, the antigen component in the complexes is matched to the disease-causing antigen, resulting in a decrease in paralysis in these models. We show that subcutaneous delivery of assemblies durably prevents diseases and drives tolerance by regulatory remodeling of the draining lymph node. Importantly, we show that subcutaneously delivered assemblies recruit and expand antigen-specific regulatory T cells (T REGS ) in draining lymph nodes. Finally, we find a shift of these recruited T REGS from a resting to an activated phenotype. Taken together, these data inform the design of therapeutics for antigen-specific tolerance that could combat autoimmunity by exploiting the role of innate pathways in a disease.

Background: Mesenchymal stromal cell (MSC) therapy commonly involves systemic infusion of MSCs, which undergo apoptosis in the lung and induce immunoregulatory macrophages that reduce disease. The relevance of this mode of action, however, is yet to be determined for MSCs administered via other routes. Here, we administered MSCs via subcutaneous (SC) injection into inflamed tissue and investigated the immunomodulatory effects on the local lymph node (LN), which is a major site for the initiation and regulation of immune responses., Methods: A mouse model of localised skin inflammation was established with low-dose lipopolysaccharide (LPS) to in vivo prime adipose-derived MSCs delivered via SC injection. We then analysed the immunomodulatory changes in the LN draining the inflamed tissue, as well as the neutrophil TNF response to LPS re-exposure., Results: When administered directly into the inflamed skin tissue, SC MSC injection induced an expansion of IL-10-producing MerTK + subcapsular sinus macrophages and T cell zone macrophages, as well as activated CD44 + regulatory T cells (Tregs), in the draining LN, which was not observed in the non-draining LN. SC injection of viable, but not apoptotic, MSCs dampened TNF production by inflammatory cells in the draining LN when re-exposed to the inflammatory stimulus. SC injection of MSCs remote to the site of inflammation also did not attenuate the LN response to subsequent inflammatory challenge., Conclusions: MSCs delivered directly into inflamed skin activated immunoregulatory cells in the local LN and inhibited LN responsiveness to subsequent inflammatory challenge. The immunoregulatory effects of SC-injected MSCs in the LN require priming by inflammatory cytokines in the local milieu. Furthermore, SC-injected MSCs exert anti-inflammatory effects in the draining LN prior to their apoptosis, in contrast to intravenously delivered MSCs, where anti-inflammatory effects are linked to their apoptosis., Competing Interests: Declarations Ethics approval and consent to participate All animal experiments received approval from Monash University Animal Ethics Committee (Project title: Mesenchymal stromal cells and the innate immune system; Approval number: 23407; Date of approval: 01/04/2020) and were performed in accordance with the guidelines of the Australian Code of Practice for the Care and Use of Animals for Scientific Purposes. Human MSCs were isolated from healthy donor lipoaspirate, performed with informed patient consent in accordance with Monash University Human Research Ethics Committee (Project title: Immunomodulatory properties of different stem cell types; Approval number: 2007/1798; Date of approval: 10/10/2007). Consent for publication Not applicable. Competing interests TSPH had received funding from Regeneus Ltd. MRH had also undertaken other related funded research for Regeneus Ltd. FM, CM and GV were employees of Regeneus Ltd. The funders were not involved in the study design, collection, analysis or interpretation of data, the writing of this article or the decision to submit it for publication. The remaining authors declare no competing interests., (© 2024. The Author(s).)

Background: Tumor-infiltrating regulatory T cells (TI-Tregs) are well-adapted to thrive in the challenging tumor microenvironment (TME) by undergoing metabolic reprogramming, notably shifting from glycolysis to mitochondrial oxidative phosphorylation (OXPHOS) for energy production. The extracellular matrix is an important component of the TME, contributing to the regulation of both tumor and immune cell metabolism patterns by activating mechanosensors such as YAP. Whether YAP plays a part in regulating TI-Treg mitochondrial function and the underlying mechanisms are yet to be elucidated., Methods: To gain insights into the effect of matrix stiffness on YAP activation in Tregs, alterations in stiffness were performed both in vitro and in vivo . YAP conditional knockout mice were used to determine the role of YAP in TI-Tregs. RNA-seq, quantitative PCR, flow cytometry, lentivirus infection and mitochondrial function assay were employed to uncover the mechanism of YAP modulating mitochondrial function in TI-Tregs. A YAP inhibitor and a low leucine diet were applied to tumor-bearing mice to seek the potential antitumor strategy., Results: In this study, we found that YAP, as a mechanotransducer, was activated by matrix stiffness in TI-Tregs. A deficiency in YAP significantly hindered the immunosuppressive capability of TI-Tregs by disrupting mitochondrial function. Mechanically, YAP enhanced mitochondrial OXPHOS by upregulating the transcription of Lars2 (Leucyl-tRNA synthetase 2, mitochondrial), which was essential for mitochondrial protein translation in TI-Tregs. Since Lars2 relied much on its substrate amino acid, leucine, the combination of a low leucine diet and YAP inhibitor synergistically induced mitochondrial dysfunction in TI-Tregs, ultimately restraining tumor growth., Conclusions: This finding uncovered a new understanding of how YAP shapes mitochondrial function in TI-Tregs in response to mechanical signals within the TME, making the combined strategy of traditional medicine and diet adjustment a promising approach for tumor therapy., Competing Interests: Competing interests: No, there are no competing interests., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

BACKGROUND Adipose-derived stem cells (ASCs) from intra-articular adipose tissue of osteoarthritis (OA) and rheumatoid arthritis (RA) patients similarly regulate the proliferation of activated CD4⁺ T lymphocytes and exhibit comparable differentiation potential. This study aimed to assess the impact of ASCs from RA patients on CD4⁺ T cell activation and differentiation into Th17 and T regulatory (Treg) cells. MATERIAL AND METHODS Intra-articular adipose tissue samples were obtained from patients with RA and OA, who underwent knee replacement surgery. ASCs were isolated and cultured either with isolated CD4⁺ cells or with peripheral blood mononuclear cells. After culture, CD4⁺ T cell phenotype was evaluated by flow cytometry, and cytokine concentrations in culture supernatants were analyzed via ELISA. Blocking experiments were conducted to identify the soluble agents responsible for the immunomodulatory effects of ASCs. RESULTS RA- and OA-derived ASCs effectively modulated CD25 and CD69 expression on CD4⁺ cells. RA-derived ASCs failed to induce Tregs, decreased HLA-DR expression, and increased IL-35 production. RA- and OA-derived ASCs reduced TNF and IFN-γ production but increased IL-17 production. The immunomodulatory activities of ASCs were linked to the kynurenine pathway and prostaglandin E2. CONCLUSIONS This study indicates that ASCs modulate the phenotype of CD4⁺ T cells and influence the production of both pro-inflammatory and anti-inflammatory cytokines. However, ASCs from RA patients appear to have impaired immunomodulatory abilities, raising concerns about their therapeutic potential. Further research is needed to enhance our understanding of ASCs biology and their therapeutic utility.

Plerixafor, a hematopoietic stem cell mobilization agent, increases the peripheral blood content of effector and regulatory T cells and may have beneficial effects on cardiac allograft vasculopathy. The aim of the current study was to evaluate its effects in a murine aortic allograft model using different application procedures. Allogeneic donor aorta grafts (n = 8/group) from C57BL/6 mice(H2b) were abdominally transplanted into CBA mice (H2k). Plerixafor application was performed either continuously for 14 d using abdominally implanted osmotic pumps (1 mg/kg/d) or i.p. with a single dose (1 and 5 mg/kg) on day 0 or pulsed injections of 1 mg/kg on days 0, 7, 14, and 21. Cell distribution was monitored by FACS. Aortic grafts were evaluated for neointima development by Elastica-van-Gieson on day 30. Immunofluorescence and intragraft gene expression analysis were performed. On day 14, significantly fewer hematopoietic stem cells were found in the bone marrow of all plerixafor-treated mice. In the pulsed application group, significantly more hematopoietic stem cells were found in the peripheral blood on day 14 (0.045 ± 0.002%; p < 0.01 [pulsed]; versus 0.0068 ± 0.002% [control]) and also more regulatory T cells. PCR revealed lower inflammatory cytokines. The luminal occlusion was significantly reduced in the pulsed treated group (33.65 ± 8.84 versus 53.13 ± 12.41) going along with decreased neointimal CD4+ T cell and plasmacytoid dendritic cell infiltration, as well as less smooth muscle cell proliferation. The application of plerixafor attenuates chronic rejection in aortic allografts via immunomodulatory effects. Injection of repeated low-dose plerixafor is the most effective application form in the aortic transplant model., (Copyright © 2024 by The American Association of Immunologists, Inc.)

Expression of T cell Ig and mucin domain-containing protein 3 (Tim-3) is upregulated on regulatory T cells (Tregs) during chronic viral infections. In several murine and human chronic infections, the expression of Tim-3 is associated with poor control of viral burden and impaired antiviral immune responses. However, the role of Tim-3+ Tregs during persistent viral infections has not been fully defined. We employed an inducible Treg-specific Tim-3 loss-of-function (Tim-3 Treg knockout) murine model to dissect the role of Tim-3 on Tregs during chronic lymphocytic choriomeningitis virus infection. Tim-3 Treg knockout mice exhibited a decrease in morbidity, a more potent virus-specific T cell response, and a significant decrease in viral burden. These mice also had a reduction in the frequency of PD-1+Tim-3+ and PD-1+Tox+ gp33-specific exhausted CD8+ T cells. Our findings demonstrate that modulation of a single surface protein on Tregs can lead to a reduction in viral burden, limit T cell exhaustion, and enhance gp33-specific T cell response. These studies may help to identify Tim-3-directed therapies for the management of persistent infections and cancer., (Copyright © 2024 by The American Association of Immunologists, Inc.)

Objective: The aim of this study was to characterize T-cell activation, exhaustion, maturation and Treg frequencies in individuals who acquire perinatal HIV (PHIV), in individuals who acquired HIV as adult (AHIV), and in healthy controls., Design: This cross-sectional study included people with HIV at least 14 and younger than 40 years, HIV-RNA less than 50 copies/ml on antiretroviral therapy for at least 6 months, and HC., Methods: We assessed the expression of PD-1, TIM-3, EOMES, CD38 + DR+, maturation status by CD4 + and CD8 + T cells and the frequency of CD4 + and CD8 + Treg cells. Principal component analysis (PCA) and k-means cluster analysis investigated which combination of immunological parameters better associated with each group., Results: Twenty-six PHIV and 18 AHIV with median ages of 26 (8.0) and 28 (6.8) years were consecutively enrolled. PHIV showed significant higher frequency of naive and lower frequency of terminal effector memory CD4 + and CD8 + T cells than AHIV. AHIV exhibited higher expression of exhaustion and activation markers. The statistical analysis returned two clusters with 94% of specificity and 88% of sensitivity identifying PHIV vs. AHIV. The nine healthy controls had a lower expression of exhaustion markers on both CD4 + and CD8 + T lymphocytes than PHIV and AHIV., Conclusion: These data may exclude major alterations of lymphopoiesis in PHIV, with even lower state of immune-activation and exhaustion compared with AHIV. This suggests that recent lack of virological control, may affect immune activation and exhaustion of CD4 + and CD8 + T cells., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background: Systemic lupus erythematosus (SLE) is an autoimmune disorder associated with the decrease and functional impairment of regulatory T cells (Tregs). In the current study, we explored the interplay of miR-155 and suppressor of cytokine signaling 1 (SOCS1) in regulating Treg function and stability in SLE., Methods: Clinical samples from healthy subjects and SLE patients were collected, and a mouse model of SLE was established to profile the expression pattern of miR-155 and SCOS1 in Tregs. Tregs isolated from mouse spleen were stimulated by inflammatory cytokines to confirm involvement of miR-155/SOCS1 axis in dictating Treg stability and function. We also administrated synthetic miR-155 inhibitor in SLE animal model to evaluate the potential effect on rescuing Treg function and alleviating SLE progression., Results: Tregs from SLE patients and SLE-induced mice exhibited a downregulation of SOCS1 and an upregulation of miR-155. In Tregs stimulated by inflammatory cytokines, Nuclear factor kappa B (NF-κB) signaling activation was required for the change of SOCS1 and miR-155 expression. miR-155 served as a negative regulator to dampen SOCS1 expression in inflammation-stimulated Tregs. The transfection of miR-155 mimic impaired the suppressive function and differentiation of Tregs through targeting SOCS1. In contrast, miR-155 inhibition improved Treg function under inflammatory stimulation and alleviated SLE conditions in the mouse model., Conclusion: Inflammation-induced miR-155 impairs Treg stability and function in SLE through decreasing SOCS1 expression. Targeting miR-155 might be developed as an intervention to mitigate SLE conditions., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

The establishment and maintenance of a successful pregnancy rely heavily on maternal-fetal immune tolerance. Inflammatory and immune mechanisms during pregnancy bear a resemblance to those observed in tumor progression, with Treg cells exhibiting similar immunoregulatory functions in both contexts. Interferon regulatory factor 1 (IRF1) is implicated in modulating the immune milieu within tumors and influencing regulatory T (Treg) cell differentiation. However, the precise association between IRF1 and the onset of preeclampsia (PE) remains unclear. In our investigation, we identified trophoblasts as a significant source of IRF1 expression at the maternal-fetal interface through immunofluorescence analysis. Moreover, heightened levels of IRF1 expression were detected in both placental tissues and peripheral blood samples obtained from PE patients, concomitant with an imbalance in the Th17/Treg ratio. In the peripheral circulation, a notable inverse correlation was observed between IRF1 mRNA levels and Foxp3 mRNA, a transcription factor specific to Treg cells. IRF1 mRNA expression showed a positive association with systolic blood pressure and a negative association with serum albumin levels. Furthermore, co-culturing naïve T cells with supernatants from HTR-8/SV neo cells overexpressing IRF1 resulted in diminished differentiation of T cells into Treg cells. In summary, our study indicates elevated IRF1 expression in the peripheral blood and trophoblast cells of PE patients. Elevated IRF1 in trophoblast cells hinders the differentiation of maternal Treg cells, disrupting maternal-fetal immune tolerance and contributing to PE pathogenesis. Additionally, IRF1 expression correlates with disease severity, suggesting its potential as a novel sensitive target in PE., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Smoke inhalation injury (SII) is the leading cause of death in fire burn patients. The inflammatory response induced by smoke inhalation is a significant factor in the development of acute lung injury or acute respiratory distress syndrome (ALI/ARDS). Mesenchymal stem cells (MSCs) can alleviate various inflammatory diseases by regulating the polarization of macrophages from the M1 to the M2 phenotype. Moreover, MSCs can facilitate the inflammatory response by regulating Th17/Treg homeostasis. However, little is known about the associations among MSCs, M1/M2 macrophages and Th17/Treg homeostasis. Therefore, the purpose of this study was to evaluate whether MSCs affect subsequent Th17/Treg differentiation and immune homeostasis by regulating M1/M2 polarization in SII. Our results showed that bone marrow mesenchymal stem cells (BMSCs) ameliorated lung inflammatory injury and fibrosis after SII by affecting the polarization of alveolar macrophages (AMs) from the M1 to the M2 phenotype. Moreover, BMSCs maintain Th17/Treg immune homeostasis by increasing the proportion of Treg cells and decreasing the proportion of Th17 cells. In vitro, we further demonstrated that BMSCs promoted the polarization of AMs from the M1 to the M2 phenotype and decreased IL-23 levels. Reduced IL-23 decreased Th17 differentiation and promoted Th17/Treg balance. Therefore, BMSCs ameliorate the inflammatory response and lung damage after SII through regulating M1/M2 polarization and subsequent Th17/Treg immune homeostasis, which are linked to alveolar macrophage-derived IL-23. These findings provide novel insight into how BMSCs regulate the M1/M2-Th17/Treg immune homeostasis axis and provide new therapeutic targets for more effective control of the inflammatory response after SII., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

The widespread use of microplastics and their harmful effects on the environment have emerged as serious concerns. However, the effect of microplastics on the immune system of mammals, particularly their offspring, has received little attention. In this study, polystyrene microplastics (PS-MPs) were orally administered to male mice during lactation. Flow cytometry was used to assess the immune cells in the spleens of both adult male mice and their offspring. The results showed that mice exposed to PS-MPs exhibited an increase in spleen weight and an elevated number of B and regulatory T cells (Tregs), irrespective of dosage. Furthermore, the F 1 male offspring of the PS-MPs-exposed group had enlarged spleens; an increased number of B cells, T helper cells (Th cells), and Tregs; and an elevated ratio of T helper cells 17 (Th17 cells) to Tregs and T helper cells 1 (Th1 cells) to T helper cells 2 (Th2 cells). These results suggested a pro-inflammatory state in the spleen. In contrast, in the F 1 female offspring exposed to PS-MPs, the changes in splenic immune cells were less pronounced. In the F 2 generation of mice with exposed to PS-MPs, minimal alterations were observed in spleen immune cells and morphology. In conclusion, our study demonstrated that exposure to real human doses of PS-MPs during lactation in male mice altered the immune status, which can be passed on to F 1 offspring but is not inherited across generations., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Glioma, a complex and aggressive brain tumor, is characterized by dysregulated immune responses within the tumor microenvironment (TME). We conducted a comprehensive analysis to elucidate the roles of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs) in glioma progression and their impact on the immune landscape. Using transcriptome data, we stratified glioma samples based on MDSC and Treg levels, revealing significant differences in patient survival probabilities. LASSO regression identified a gene panel associated with glioma prognosis, yielding a patient-specific risk score. Multivariate Cox regression confirmed the risk score's correlation with overall survival. An ISS (immune suppressive score) system assessed the immune landscape's impact on glioma progression and therapeutic response. Functional validation showed MDSC and Treg infiltration's relevance in glioma progression and immune modulation. Hub genes in the black module, including CCL2, LINC01503, CXCL8, CLEC2B, TIMP1, and RGS2, were identified through MCODE analysis. RGS2 expression correlated with immune cell populations and varied in glioma cells. This study sheds light on MDSCs' and Tregs' roles in glioma pathogenesis, suggesting their potential as prognostic biomarkers and therapeutic targets for personalized immunotherapeutic strategies in glioma treatment., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The epigenome of T follicular helper cells prepares them for conversion into type 1 regulatory T cells., Competing Interests: DT, XW No competing interests declared, (© 2024, Turicek and Wan.)

It has long been known that T cells participate in wound healing; however, the landscape of the signaling derived from T cells in the process of wound healing is still enigmatic. With the advantages of scRNA-seq, in combination with immunofluorescent imaging, we identified activated T cells, cytotoxic T cells (CTLs), exhausting T cells, and Tregs existing in the inflammation phase of wound healing. Further analysis revealed each T cell population possess distinguished signals contributed to wound healing, some are critical for improving the wound healing quality. Besides, this study discovered and validated the existence of exhausting T cells among the T cells accumulated in the skin during wound healing, and the molecular mechanism(s) and contribution of exhausting T cells to wound healing deserve extensive studies in the future., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Burn Association. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

The prevalence of obesity and its associated metabolic disorders has emerged as one of the most significant health threats worldwide. The visceral adipose tissue regulatory T cells (VAT Treg) play an essential role in maintaining homeostasis and preventing obesity mainly by secreting Interleikin-10 (IL-10) and Transforming Growth Factor β (TGF-β). However, the mechanism that regulates VAT Treg quantity and function remains unclear. Here we elucidate the pivotal role of IL-27 signaling in sustaining the accumulation of VAT Treg cells, thereby conferring protection against obesity. We found that mice with the deficiency of IL-27 receptor Wsx1 gained more body weight and VAT weight than their wild-type littermates when fed both a normal-fat diet (NFD) and a high-fat diet (HFD). Notably, the population of VAT Treg cells was reduced in Wsx1 knockout (KO) mice, regardless of whether they were fed a normal-fat diet (NFD) or a high-fat diet (HFD). Correspondingly, the expression levels of the transcription factors FOXP3 and PPAR-γ, essential for VAT Treg function, were also diminished in Wsx1 KO mice. Taken together, our findings indicate that IL-27 signaling plays a protective role in obesity by supporting the maintenance and accumulation of VAT Treg cells., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Lymphocyte activation gene 3 (Lag3) is an inhibitory co-receptor expressed on activated T cells and has been proposed to regulate regulatory T (Treg) cell function. However, its precise modality and mechanisms remain elusive. We generated Treg cell-specific Lag3-mutant mouse models and found that Lag3 was essential for Treg cell control of autoimmunity. RNA sequencing analysis revealed that Lag3 mutation altered genes associated with metabolic processes, especially Myc target genes. Myc expression in Lag3-mutant Treg cells was increased to the level seen in conventional T helper (Th)1-type effector cells and directly correlated with their metabolic profiles and in vivo suppressive functions. The phosphatidylinositol 3-kinase (PI3K)-Akt-Rictor pathway was activated in Lag3-mutant Treg cells, and inhibiting PI3K, Rictor, or lactate dehydrogenase A (Ldha), a key Myc target enzyme converting pyruvate to lactate, was sufficient to restore normal metabolism and suppressive function in Lag3-mutant Treg cells. These findings indicate that Lag3 supports Treg cell suppression partly by tuning Myc-dependent metabolic programming., Competing Interests: Declaration of interests J.C. is a founder and shareholder in Moonlight Bio., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Acquired aplastic anemia (AA) often results from immune destruction of hematopoietic stem and progenitor cells. However, only 60%-70% of patients with AA respond to immunosuppressive therapy (IST). There is a lack of strong predictive markers for response to IST which can help therapy. Our study sought to pinpoint unique immune markers in AA patients and validate established predictors for response to IST. We enrolled 51 severe AA patients and analyzed 57 immunological parameters via flow cytometry. Additionally, we measured paroxysmal nocturnal hemoglobinuria (PNH) clone, telomere length, and thrombopoietin (TPO) levels prior to IST. After a 6-month follow-up, a response was observed. Patients with AA had a distinct immunological signature characterized by absolute lymphopenia, skewed CD4/CD8 ratio with expansion of CD8 T cells with activated and senescent phenotype. Treg counts were reduced, while the proportion of Treg A and B was comparable to controls. Treatment response was correlated with elevated absolute neutrophil count (ANC), absolute reticulocyte count (ARC), and reduced CD57+ CD8+ naive cells and B cell % before therapy. However, predictors like TPO, telomere length, and PNH did not emerge as indicators of treatment response. Identifying predictors for treatment response in AA is challenging due to abnormal hematopoiesis, genetic mutations, and treatment variables., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Immunology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Cellular phenotype and function are altered in different microenvironments. For targeted therapies it is important to understand site-specific cellular adaptations. Juvenile idiopathic arthritis (JIA) is characterized by autoimmune joint inflammation, with frequent inadequate treatment responses. To comprehensively assess the inflammatory immune landscape, we designed a 37-parameter spectral flow cytometry panel delineating mononuclear cells from JIA synovial fluid (SF) of autoimmune inflamed joints, compared to JIA and healthy control blood. Synovial monocytes and NK cells (CD56bright) lack Fc-receptor CD16, suggesting antibody-mediated targeting may be ineffective. B cells and DCs, both in small frequencies in SF, undergo maturation with high 4-1BB, CD71, CD39 expression, supporting T-cell activation. SF effector and regulatory T cells were highly active with newly described co-receptor combinations that may alter function, and suggestion of metabolic reprogramming via CD71, TNFR2, and PD-1. Most SF effector phenotypes, as well as an identified CD4-Foxp3+ T-cell population, were restricted to the inflamed joint, yet specific SF-predominant CD4+ Foxp3+ Treg subpopulations were increased in blood of active but not inactive JIA, suggesting possible recirculation and loss of immunoregulation at distal sites. This first comprehensive dataset of the site-specific inflammatory landscape at protein level will inform functional studies and the development of targeted therapeutics to restore immunoregulatory balance and achieve remission in JIA., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Immunology.)

Background: Medication overuse headache (MOH) is the most common secondary headache disorder, resulting from chronic and excessive use of medication to treat headaches, for example, sumatriptan. In a recent study, we have shown that the peripheral C-C motif ligand 2 (CCL2), C-C motif chemokine receptor 2 (CCR2) and calcitonin-gene-related peptide (CGRP) signaling pathways interact with each other and play critical roles in the development of chronic migraine-related behavioral and cellular sensitization. In the present study, we investigated whether CCL2-CCR2 and CGRP signaling pathways play a role in the development of sumatriptan overuse-induced sensitization, and whether they are involved in its resolution by the low-dose interleukin-2 (LD-IL-2) treatment., Methods: Mice received daily sumatriptan administration for 12 days. MOH-related behavioral sensitization was assessed by measuring changes of periorbital mechanical thresholds for 3 weeks. CCL2-CCR2 and CGRP signaling pathways were inhibited by targeted gene deletion or with an anti-CCL2 antibody. Ca 2+ -imaging was used to examine whether repetitive sumatriptan treatment enhances CGRP and pituitary adenylate cyclase-activating polypeptide (PACAP) signaling in trigeminal ganglion (TG) neurons. LD-IL-2 treatment was initiated after the establishment of sumatriptan-induced sensitization. Immunohistochemistry and flow cytometry analyses were used to examine whether CCL2-CCR2 signaling controls regulatory T (Treg) cell proliferation and/or trafficking., Results: CCL2, CCR2 and CGRPα global KO mice exhibited robust sumatriptan-induced behavioral sensitization comparable to wild-type controls. Antibody neutralization of peripheral CCL2 did not affect sumatriptan-induced behaviors either. Repeated sumatriptan administration did not enhance the strength of CGRP or PACAP signaling in TG neurons. Nevertheless, LD-IL-2 treatment, which facilitated the resolution of sumatriptan-induced sensitization in wild-type and CGRPα KO mice, was completely ineffective in mice with compromised CCL2-CCR2 signaling. In CCL2 KO mice, we observed normal LD-IL-2-induced Treg expansion in peripheral blood, but the increase of Treg cells in dura and TG tissues was significantly reduced in LD-IL-2-treated CCL2 KO mice relative to wild-type controls., Conclusions: These results indicate that the endogenous CCL2-CCR2 and CGRP signaling pathways are not involved in sumatriptan-induced behavioral sensitization, suggesting that distinct molecular mechanisms underlie chronic migraine and MOH. On the other hand, peripheral CCL2-CCR2 signaling is required for LD-IL-2 to reverse chronic headache-related sensitization., Competing Interests: Declarations Ethics approval and consent to participate All procedures were carried out in accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health and were approved by the Institutional Animal Care and Use Committee at Washington University in St. Louis. Consent for publication NA. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Cow milk protein allergy (CMPA) is the most common food allergy in infants. Currently, hypoallergenic infant formulas on the market are mainly divided into extensively hydrolyzed whey protein formulas and extensively hydrolyzed casein formulas. There are few extensively hydrolyzed infant formulas (EHFs) with a similar protein composition to breast milk. Therefore, we developed a hypoallergenic infant formula based on extensively hydrolyzed cow milk protein (whey protein-to-casein ratio of 6 : 4) and evaluated its allergenicity in vitro and in vivo . The results showed that the antigenicity of EHF was significantly decreased. The levels of Treg and Th1 cells were increased, while the levels of Th2 cells, IgE and IgG1, plasma histamine and serum mast cell enzymes were significantly decreased. At the same time, the allergic symptoms of the jejunum and lungs of mice were relieved. This study provides a solution for the development of cow milk protein based hypoallergenic infant formulas.

At present, the characteristics of double-hit multiple myeloma (DHMM) are unknown. We retrospectively analyzed the clinical data from 433 new diagnosed MM patients and found that DHMM have a higher β2-MG level and percentage of bone marrow plasma cell. Cox regression analysis showed that the prognosis of DHMM was not limited by clinical indicators. The abnormal proliferation of bone marrow in DHMM is obvious, and the proportion of poorly differentiated plasma cell is high. By collecting specimens from our center and performing flow cytometry to analyze the immunophenotypic and functional characteristics of lymphocyte subpopulations, we found that DHMM had a higher ratio of Tregs cells, and the proportion of iTregs cells was also significantly higher than non-DHMM (P < 0.05). Moreover, DHMM had higher levels of TGF-β1 and IL-10, and TGF-β1 and IL-10 were positively correlated with iTregs (P < 0.05). In addition, DHMM was highly expressed PD-1 on CD8 + T cells and had a higher proportion of CD38 high Tregs cells. In vitro we have shown that the addition of TGF-β1 antibody or CD38 antibody can effectively inhibit the proportion of CD38 high Tregs. This study describes the characteristics of DHMM based on bicentric data, which is helpful to better provide theoretical support for the treatment of DHMM., Competing Interests: Declarations Ethics approval and consent to participate The studies involving human subjects were reviewed and approved by the Ethics Committee at Zhongnan Hospital of Wuhan University. The patients provided their written informed consent to participate in this study. All methods were carried out in accordance with declaration of Helsinki. Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Regulatory T cells (Tregs), an essential component of the human immune system, are a heterogeneous group of T lymphocytes with the ability to suppress immune responses and maintain immune homeostasis. Recent evidence indicates that Tregs may impair antitumor immunity and facilitate cancer progression by weakening functions of effector T cells (Teffs). Consequently, targeting Tregs to eliminate them from tumor microenvironments to improve Teffs' activity could emerge as an effective strategy for cancer immunotherapy. This review outlines the biology of Tregs, detailing their origins, classification, and crucial markers. Our focus lies on the complex role of Tregs in cancer's development, progression and treatment, particularly on their suppressive role upon antitumor responses via multiple mechanisms. We delve into Tregs' involvement in immune checkpoint blockade (ICB) therapy, their dual effect on cancer immunotherapy and their potential biomarkers for ICB therapy effectiveness. We also summarize advances in the therapies that adjust Tregs to optimize ICB therapy, which may be crucial for devising innovative cancer treatment strategies., (© 2024. The Author(s).)

This study investigates the variability among patients with non-small cell lung cancer (NSCLC) in their responses to immune checkpoint inhibitors (ICIs). Recognizing that patients with advanced-stage NSCLC rarely qualify for surgical interventions, it becomes crucial to identify biomarkers that influence responses to ICI therapy. We conducted an analysis of single-cell transcriptomes from 33 lung cancer biopsy samples, with a particular focus on 14 core samples taken before the initiation of palliative ICI treatment. Our objective was to link tumor and immune cell profiles with patient responses to ICI. We discovered that ICI non-responders exhibited a higher presence of CD4+ regulatory T cells, resident memory T cells, and TH17 cells. This contrasts with the diverse activated CD8+ T cells found in responders. Furthermore, tumor cells in non-responders frequently showed heightened transcriptional activity in the NF-kB and STAT3 pathways, suggesting a potential inherent resistance to ICI therapy. Through the integration of immune cell profiles and tumor molecular signatures, we achieved an discriminative power (area under the curve [AUC]) exceeding 95% in identifying patient responses to ICI treatment. These results underscore the crucial importance of the interplay between tumor and immune microenvironment, including within metastatic sites, in affecting the effectiveness of ICIs in NSCLC., Competing Interests: NK, SP, AJ, HE, HK, KL, JC, BK, HJ, JS, SL, JA, JL, JC, DJ, MN, HK, JK, JC, HL, MA No competing interests declared, (© 2024, Kim, Park et al.)

The function of PD-1/PD-L1 axis have been intensively studied for immune escape of various cancers. However, the underlying function of PD-L2 remains poorly understood. Here, we demonstrate that PD-L2 is majorly expressed in exosomes with surface localization by clear cell renal cell carcinoma (ccRCC) cells. Tumor cell-derived exosome PD-L2 (TDE-PD-L2) exhibits high expression compared with TDE-PD-L1 in various cancers. In the absence of adaptive immune, TDE-PD-L2 suppresses tumor growth and metastasis. Under immune competence condition, TDE-PD-L2 is hijacked by immune cells in a PD-1-dependent manner to systematically dampen function of T cells via the increased proportion of the regulatory T cells and the decreased proportion of cytotoxic CD8 + T cells in both tumor-infiltrating T cells and spleen. The effects of TDE-PD-L2 on tumor is restored by antibodies targeting PD-L2. Collectively, we demonstrate that PD-1/TDE-PD-L2 axis systematically suppresses T cell functions, representing a potentially therapeutic strategy for ccRCC treatment., (© 2024. The Author(s).)

Ulcerative colitis (UC) is a common chronic, relapsing inflammatory bowel condition. Procyanidins (PC) are known for their antiangiogenic, anti-inflammatory, antioxidant, and antimetastatic properties. However, there is comparatively limited information on how PC interacts with UC. In this study, 5 mg/10 mL/kg body weight of PC was administered to mice with dextran sulfate sodium (DSS)-induced colitis mice. PC treatment prolonged the survival period of mice, ameliorated UC symptoms, reduced damage to the intestinal mucosal barrier, and increased the protein expression of ZO-1 and occludin in the DSS-treated mice. Importantly, PC treatment significantly reduced gene expression related to Th17 cell differentiation, including STAT3, SMAD3, TGF-β, and JAK1. The results of the flow cytometry analysis indicated significant increase in the number of Treg cells and a concomitant decrease in the proportion of Th17 cells in the colon following PC treatment. Additionally, PC increased the abundance of gut microbiota such as Bacteroidota , Oscillospiraceae , Muribaculaceae, and Desulfovibrionaceae , as well as the concentrations of acetate acid, propionate acid, and butyrate acid in the feces. PC also activated short-chain fatty acid receptors, such as G-protein coupled receptor 43 in the colon, which promoted the proliferation of Treg cells. The depletion of gut microbiota and subsequent transplantation of fecal microbiota demonstrated that PC's effects on gut microbiota were effective in improving UC and restoring intestinal Th17/Treg homeostasis in a microbiota-dependent manner. This suggests that PC could be a promising functional food for the prevention and treatment of UC in the future.

Intratumoral regulatory T cells (Tregs) express high levels of CD25 and TIGIT, which are also recognized as markers of effector T cell (Teff) activation. Targeting these molecules each alone with monoclonal antibodies (mAbs) poses a risk of concurrently depleting both Teffs and peripheral Tregs, thereby compromising the effectiveness and selectivity of intratumoral Treg depletion. Here, leveraging the increased abundance of CD25 + TIGIT + double-positive Tregs in the solid tumor microenvironment (but not in peripheral tissues), we explore the feasibility of using a CD25×TIGIT bispecific antibody (bsAb) to selectively deplete intratumoral Tregs. We initially constructed a bsAb co-targeting mouse CD25 and TIGIT, NSWm7210, and found that NSWm7210 conferred enhanced intratumoral Treg depletion, Teff activation, and tumor suppression as compared to the parental monotherapies in mouse models. We subsequently constructed a bsAb co-targeting human CD25 and TIGIT (NSWh7216), which preferentially eliminated CD25 + TIGIT + double-positive cells over single-positive cells in vitro. NSWh7216 exhibited enhanced anti-tumor activity without toxicity of peripheral Tregs in CD25 humanized mice compared to the parental monotherapies. Our study illustrates the use of CD25×TIGIT bsAbs as effective agents against solid tumors based on selective depletion of intratumoral Tregs., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Introduction: Regulatory CD8 T cells (CD8 Treg) are responsible for the selective killing of self-reactive and pathogenic CD4 T cells. In autoimmune disease, CD8 Treg may accumulate in the peripheral blood but fail to control the expansion of pathogenic CD4 T cells that subsequently cause tissue destruction. This CD8 Treg dysfunction is due in part to the expression of inhibitory killer immunoglobulin-like receptors (KIR; KIR2DL isoforms [KIR2DL1, KIR2DL2, and KIR2DL3]); these molecules serve as autoimmune checkpoints and limit CD8 Treg activation., Methods: Here we describe the pre-clinical characterization of MTX-101, a bispecific antibody targeting inhibitory KIR and CD8. Using human peripheral blood mononuculear cells (PBMC) derived from healthy donors and autoimmune patients, humanized mouse models, and human derived tissue organoids, we evaluated the molecular mechanisms and functional effects of MTX-101., Results: By binding to KIR, MTX-101 inhibited KIR signaling that can restore CD8 Treg ability to eliminate pathogenic CD4 T cells. MTX-101 bound and activated CD8 Treg in human peripheral blood mononuclear cells (PBMC), resulting in increased CD8 Treg cytolytic capacity, activation, and prevalence. Enhancing CD8 Treg function with MTX-101 reduced pathogenic CD4 T cell expansion and inflammation, without increasing pro-inflammatory cytokines or activating immune cells that express either target alone. MTX-101 reduced antigen induced epithelial cell death in disease affected tissues, including in tissue biopsies from individuals with autoimmune disease (i.e., celiac disease, Crohn's disease). The effects of MTX-101 were specific to autoreactive CD4 T cells and did not suppress responses to viral and bacterial antigens. In a human PBMC engrafted Graft versus Host Disease (GvHD) mouse model of acute inflammation, MTX-101 bound CD8 Treg and delayed onset of disease. MTX-101 induced dose dependent binding, increased prevalence and cytolytic capacity of CD8 Treg, as well as increased CD4 T cell death. MTX-101 selectively bound CD8 Treg without unwanted immune cell activation or increase of pro-inflammatory serum cytokines and exhibited an antibody-like half-life in pharmacokinetic and exploratory tolerability studies performed using IL-15 transgenic humanized mice with engrafted human lymphocytes, including CD8 Treg at physiologic ratios., Conclusion: Collectively, these data support the development of MTX-101 for the treatment of autoimmune diseases., Competing Interests: The authors were employed by Mozart Therapeutics and declare that the study was funded by Mozart Therapeutics. Mozart Therapeutics was involved in the study design, collection, analysis, interpretation of data, the writing of this article, and the decision to submit it for publication., (Copyright © 2024 Gardell, Maurer, Childs, Pham, Meengs, Julien, Tan, Boster, Quach, Therriault, Hermansky, Patton, Bowser, Chen, Morgan, Gilbertson, Bogatzki, Encarnacion, McMahan, Crane and Swiderek.)

Regulatory T cells (Treg) are important players in the tumor microenvironment. However, the mechanisms behind their immunosuppressive effects are poorly understood. We found that CCR6-CCL20 activity in tumor-infiltrating Tregs is associated with greater glycolytic activity and ablation of Ccr6 reduced glycolysis and lactic acid production while increasing compensatory glutamine metabolism. Immunosuppressive activity toward CD8+ T cells was abrogated in Ccr6-/- Tregs due to reduction in activation-induced glycolysis. Furthermore, Ccr6-/- mice exhibited improved survival across multiple tumor models compared to wild-type mice and Treg and CD8+ T-cell depletion abrogated the improvement. In addition, Ccr6 ablation further promoted the efficacy of anti-PD-1 therapy in a preclinical glioma model. Follow-up knockdown of Ccl20 with siRNA also demonstrated improvement in antitumor efficacy. Our results unveil CCR6 as a marker and regulator of Treg-induced immunosuppression and identify approaches to target the metabolic determinants of Treg immunosuppressive activity., (©2024 American Association for Cancer Research.)

Regulatory T cells play a crucial role in the homeostasis of the immune response. Regulatory T cells are mainly generated in the thymus and are characterized by the expression of Foxp3, which is considered the regulatory T-cell master transcription factor. In addition, regulatory T cells can be induced from naive CD4+ T cells to express Foxp3 under specific conditions both in vivo (peripheral regulatory T cells) and in vitro (induced regulatory T cells). Both subsets of thymic regulatory T cells and peripheral regulatory T cells are necessary for the establishment of immune tolerance to self and non-self antigens. Although it has been postulated that induced regulatory T cells may be less stable compared to regulatory T cells, mainly due to epigenetic differences, accumulating evidence in animal models shows that induced regulatory T cells are stable in vivo and can be used for the treatment of inflammatory disorders, including autoimmune diseases and allogeneic transplant rejection. In this review, we describe the biological characteristics of induced regulatory T cells, as well as the key factors involved in induced regulatory T-cell transcriptional, metabolic, and epigenetic regulation, and discuss recent advances for de novo generation of stable regulatory T cells and their use as immunotherapeutic tools in different experimental models. Moreover, we discuss the challenges and considerations for the application of induced regulatory T cells in clinical trials and describe the new approaches proposed to achieve in vivo stability, including functional or metabolic reprogramming and epigenetic editing., Competing Interests: Conflict of interest statement. None., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Leukocyte Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

T cell immunoglobulin and ITIM domain (TIGIT) is an immune checkpoint molecule that suppresses T cell activation and promotes an immunosuppressive environment to suppress autoimmune diseases. However, the impact of a TIGIT agonist as a treatment for ocular autoimmune disease has not been investigated. We examined TIGIT expression on T helper 17 (Th17) and regulatory T cells (Tregs), the role of TIGIT on experimental autoimmune uveitis and Th17 cells, and the impact of Treg generation following TIGIT stimulation. TIGIT stimulation at the onset of clinical symptoms reduced the severity of uveitis and suppressed infiltration of Th17 cells into the eye. Further, Tregs from mice treated with the TIGIT agonist were capable of suppressing experimental autoimmune uveitis in recipient mice. This report demonstrates that stimulation of TIGIT at onset of disease suppresses symptoms and allows for induction of regulatory immunity that provides resistance to uveitis., Competing Interests: Conflict of interest statement. None declared., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for Leukocyte Biology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

COVID-19, caused by SARS-CoV-2, triggers a complex immune response, with T regulatory cells (Tregs) playing a crucial role in maintaining immune homeostasis and preventing excessive inflammation. The current study investigates the function of T regulatory cells during COVID-19 infection and the subsequent recovery period, emphasizing their impact on immune regulation and inflammation control. We conducted a comprehensive analysis of Treg subpopulations in peripheral blood samples from COVID-19 patients at different stages: acute infection, early convalescence, and long-term recovery. Flow cytometry was employed to quantify Tregs including "naïve", central memory (CM), effector memory (EM), and terminally differentiated CD45RA + effector cells (TEMRA). Additionally, the functional state of the Tregs was assessed by the expression of purinergic signaling molecules (CD39, CD73). Cytokine profiles were assessed through multiplex analysis. Our findings indicate a significant decrease in the number of Tregs during the acute phase of COVID-19, which correlates with heightened inflammatory markers and increased disease severity. Specifically, we found a decrease in the relative numbers of "naïve" and an increase in EM Tregs, as well as a decrease in the absolute numbers of "naïve" and CM Tregs. During the early convalescent period, the absolute counts of all Treg populations tended to increase, accompanied by a reduction in pro-inflammatory cytokines. Despite this, one year after recovery, the decreased subpopulations of regulatory T cells had not yet reached the levels observed in healthy donors. Finally, we observed the re-establishment of CD39 expression in all Treg subsets; however, there was no change in CD73 expression among Tregs. Understanding these immunological changes across different T regulatory subsets and adenosine signaling pathways offers important insights into the disease's pathogenesis and provides a broader view of immune system dynamics during recovery.

Sublingual immunotherapy (SLIT) has received considerable attention as a method for allergen immunotherapy (AIT). However, the mechanism of SLIT, especially its timing, has not been thoroughly investigated. We evaluated therapeutic and prophylactic SLIT in an allergic airway inflammation model and evaluated their efficacies. Mice were intranasally exposed to Dermatophagoides farinae (Der f) extract and received SLIT before (prophylactic model) and after (therapeutic model) intranasal exposure of Der f. We investigated airway responsiveness, airway inflammation, allergen-specific antibodies, lung histology and single-cell RNA sequencing (scRNA-seq) and T-cell receptor sequencing were also investigated. SLIT in the therapeutic model was effective; however, the effects of SLIT in the prophylactic model were stronger and immune tolerance was maintained for three months. ScRNA-seq of lung CD4 + CD25 + T cells revealed that the expansion of induced T regulatory (iTreg) cells was greater in the prophylactic model than that in the therapeutic model. Additionally, the TCR repertoire of iTregs from the prophylactic model was abundant, sharing many clones with the TCR repertoire of effector T cells. These data suggest that the prophylactic model of AIT is extremely effective and persistent, and may respond to allergen diversity, and provide evidence for the clinical recommendation of preventive AIT., (© 2024. The Author(s).)

Drug reactions with eosinophilia and systemic symptoms (DRESS) and Stevens-Johnson syndrome/toxic epidermal necrolysis (SJS/TEN) are severe cutaneous adverse hypersensitivity reactions with distinct clinical manifestations. Regulatory T (Treg) cells may behave differently in these syndromes, contributing to their diverse clinical features and outcomes. This study compared Treg dynamics between DRESS and SJS/TEN patients during the acute and recovery phases. Flow cytometry quantitatively analysed and defined the immunophenotype of CD4 + CD25 + CD127 - FoxP3 + Tregs in blood from DRESS and SJS/TEN patients indicated that Treg percentages were lowest in DRESS patients during the acute phase compared to those in the recovery phase in DRESS patients and the acute phase in SJS/TEN patients. During the acute phase, CTLA-4 expression in Tregs in both DRESS patients with and without autoimmune sequelae was significantly increased, while only DRESS patients without autoimmune sequelae had elevated OX40 expression compared to the healthy controls. High IL-10 expression in Tregs during the acute phase in SJS/TEN patients was also observed. The suppressive function of Tregs was lower in DRESS compared to SJS/TEN, which was determined using a suppression assay by co-culturing autologous Treg and effector T cells. Furthermore, NanoString technology explored mRNA profiles in Tregs. Genes associated with the JAK/STAT pathway were found to be downregulated during the acute phase in DRESS patients who later developed autoimmune sequelae. Our findings evidenced impaired Treg function in DRESS compared to SJS/TEN. The early disturbance of the JAK/STAT pathway may serve as a prognostic marker for autoimmune development in DRESS patients., (© 2024 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Oral tolerance is essential for intestinal homeostasis and systemic immune function. However, our understanding of how oral tolerance is maintained is inadequate. Here we report that food-derived nucleic acids promote oral tolerance through innate sensing pathways. We find that dietary nucleic acids, but not microbiota, expand the natural intraepithelial lymphocyte (IEL) pool, specifically in the small intestine. TGF-β1, produced by natural IELs, then promotes activation of gut CD103 + dendritic cells to support the induction of antigen-specific Treg cells in a mouse model of OVA-induced oral tolerance. Mechanistically, MAVS and STING are redundantly required for sensing dietary RNAs and DNAs to activate downstream TBK1 signalling to induce IL-15 production, which results in the accumulation of natural IELs. Thus, our study demonstrates a key role of food-triggered innate sensing pathways in the maintenance of natural IELs and oral tolerance., (© 2024. The Author(s).)

Kirsten rat sarcoma virus (KRAS)-G12C inhibition causes remodeling of the lung tumor immune microenvironment and synergistic responses to anti-PD-1 treatment, but only in T cell infiltrated tumors. To investigate mechanisms that restrain combination immunotherapy sensitivity in immune-excluded tumors, we used imaging mass cytometry to explore cellular distribution in an immune-evasive KRAS mutant lung cancer model. Cellular spatial pattern characterization revealed a community where CD4 + and CD8 + T cells and dendritic cells were gathered, suggesting localized T cell activation. KRAS-G12C inhibition led to increased PD-1 expression, proliferation, and cytotoxicity of CD8 + T cells, and CXCL9 expression by dendritic cells, indicating an effector response. However, suppressive regulatory T cells (T regs ) were also found in frequent contact with effector T cells within this community. Lung adenocarcinoma clinical samples showed similar communities. Depleting T regs led to enhanced tumor control in combination with anti-PD-1 and KRAS-G12C inhibitor. Combining T reg depletion with KRAS inhibition shows therapeutic potential for increasing antitumoral immune responses.

OX40L-CAR-T regs show promise for treating autoimmunity and transplantation rejection.

Background/aim: Connective tissue disease-associated pulmonary arterial hypertension (CTD-PAH) is a severe complication characterized by elevated pulmonary artery pressure, which can lead to right heart failure and death, if untreated. Standard treatments often fail to adequately manage symptoms, highlighting the need for novel therapeutic approaches. This study investigated the efficacy of molecular hydrogen (H 2 ) therapy in a patient with CTD-PAH., Case Report: We present the case of a 56-year-old female with CTD-PAH, diagnosed in 2013 with Sjogren's syndrome complicated by interstitial lung disease (ILD) and PAH. Despite treatment with sildenafil, bosentan, macitentan, iloprost, and corticosteroids, her condition deteriorated, resulting in severe dyspnea and cardiogenic shock in 2020. In May 2023, molecular hydrogen therapy was initiated as an adjuvant treatment. The patient received daily hydrogen capsules, which led to increased CD127+ Treg cells, reduced anti-Ro antibodies, and decreased B cell subsets. Her clinical symptoms stabilized without adverse effects., Conclusion: This case highlights the potential benefits of molecular hydrogen therapy in CTD-PAH. H 2 therapy exhibiting anti-inflammatory and immunomodulatory effects, leading to improved immune cell profiles and stabilizing clinical symptoms in a patient unresponsive to conventional treatments. Further research is needed to elucidate the mechanisms of H 2 therapy and validate its efficacy in larger cohorts. Molecular hydrogen therapy shows promise as a safe adjunctive treatment for CTD-PAH, offering a new approach for managing this challenging condition., (Copyright © 2024, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background/aim: Most nontraumatic subarachnoid hemorrhages (SAHs) are caused by ruptured saccular aneurysms, often resulting in a devastating clinical event characterized by high mortality and significant morbidity among survivors. Numerous studies have confirmed the neuroprotective effects of the molecular hydrogen due to its unique biological properties., Case Report: We present the case of a 44-year-old female with aneurysmal SAH with rheumatoid arthritis (RA) and newly diagnosed systemic lupus erythematosus (SLE), complicated by acute ischemic infarction. Despite surgical, pharmacological and non-pharmacological interventions, including embolization of the aneurysm, immunosuppressant, non-vitamin K antagonist oral anticoagulant (NOAC), and plasmapheresis, loss of consciousness continued. The patient began daily treatment with hydrogen capsules, resulting in increased in Treg cells, Breg cells, increased TIM3+ expression on Tc cells, and the conversion of anti-dsDNA from positive to negative. Her clinical symptoms stabilized without adverse effects., Conclusion: This case highlights the potential benefits of molecular hydrogen therapy in managing aneurysmal SAH with underlying autoimmune disease, warranting further research., (Copyright © 2024, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.)

Background: Chronic lymphocytic leukemia (CLL) is characterized by a wide range of tumor-induced immune alterations. Regulatory T cells (Treg) play a central role in these immune responses. CD200 and Leukocyte-associated immunoglobulin-like receptor-1 (LAIR-1, CD305) are inhibitory markers said to be involved in Treg immune response. We aimed to analyze the expression of CD200 and LAIR-1 on leukemic cells and assess their interactions with the Treg frequency to elucidate their role in the CLL course., Subjects and Methods: This study was conducted on 70 participants: 50 newly diagnosed CLL cases classified according to Rai staging system into group 1 (n = 25) patients with stages 0, I, and II, and group 2 (n = 25) of advanced patients with stages III and IV. In addition to control group (n = 20) of healthy adults. Flow cytometry was used to investigate Treg frequency in bone marrow (BM) proportional to CD4+ T cell and to assess leukemic cell expression of CD200 and LAIR-1. Also, in-silico database analysis was performed to identify study markers interactions for future personalized target therapy., Results: Comparison between CLL groups 1 and 2 revealed increased leukemic cell percentage expressing LAIR-1 (p = 0.021) in group 1. Group 2 showed significant increase in frequency of Treg in BM and leukemic cells expressing CD200. There was a strong positive correlation between frequency of Treg and leukemic cells expressing CD200 (r = 0.669, p = 0.000). On the other hand, there was a negative correlation between frequency of Treg and leukemic cell expressing LAIR-1 (r = -0.342, p = 0.015). ROC curve analysis revealed that increased frequency of leukemic cells expressing CD200 yielded sensitivity (SN) and specificity (SP) of 96 % and 84 %, respectively in detecting CLL progression, with an AUC of 0.965. Leukemic cell percentages expressing LAIR-1 yielded a lower SN (75 %), SP (72 %), with an AUC of 0.688., Conclusion: Treg frequency in BM was significantly increased in CLL advanced stages according to Rai classification. Leukemic cells CD200 and LAIR-1 expression were differently associated with Treg frequency. Increased CD200 expressions on leukemic cells can be considered a sensitive and specific biomarker in detecting CLL progression. As demonstrated by the in-silico research, CD200 blockade targeting may offer therapeutic benefits for CLL treatment through Treg suppression., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier GmbH. All rights reserved.)

Background: Imbalances in Th1/Th2 and Th17/Treg immune axes, coupled with disruptions in the gut microbiota (GM), play a pivotal role in the pathogenesis of inflammatory bowel disease (IBD). Cordycepin, a natural anti-inflammatory compound, holds promise in mitigating IBD by rebalancing these immune axes in conjunction with modulating the GM. The aim of this experiment is to investigate the potential of cordycepin in mitigating enteritis and elucidate the underlying mechanisms associated with its ameliorative effects on enteritis., Methods: On the day of inducing experimental colitis with Dextran Sulfate Sodium (DSS), mice in the DSS + Cordycepin and Cordycepin groups received 50 mg/kg/day Cordycepin via intra-gastric administration (i.g.) for seven consecutive days, respectively. Mice in the DSS and control groups were treated with equal volumes of saline. On day 8, all mice were euthanized under pentobarbital sodium anesthesia., Results: In a DSS-induced colitis mouse model, Cordycepin treatment led to a significant reduction in the disease activity index (DAI), splenic weight, and colonic pathological injury while simultaneously improving body weight and colonic length. Furthermore, it positively impacted GM composition, resulting in decreased Th1 and Th17 cells, alongside an increase in Th2 and Treg cells. The contents of the mouse colon were extracted for microbial community analysis. Mouse blood was prepared into a single-cell suspension, and flow cytometry was used to assess the expressio of Treg, Th17, Th1, and Th2 immune cells., Conclusions: These results underscored the effective intervention of cordycepin in ameliorating DSS-induced colitis by harmonizing the interplay between GM and immune homeostasis., Competing Interests: Declaration of Competing Interest I, Jingting Jiang, declare that there are no conflicts of interest in relation to the manuscript titled "Cordycepin Mitigates Dextran Sulfate Sodium-Induced Colitis through Improving Gut Microbiota Composition and Modulating Th1/Th2 and Th17/Treg Balance" submitted to Biomedicine Pharmacotherapy. I confirm that the results and interpretations reported in the manuscript are original and have not been plagiarized. I certify that I have read and understand the Biomedicine Pharmacotherapy conflict of interest policy, and I understand that failure to disclose a conflict of interest may result in the manuscript being rejected or retracted. I also certify that I have disclosed any financial or non-financial relationships that may be interpreted as constituting a conflict of interest in relation to this manuscript. I understand that this information will be subject to peer review, and I am willing to provide further information or clarification if required. I confirm that I have no known conflicts of interest that would influence the results or interpretation of the data presented in this manuscript, and I understand that failure to disclose a conflict of interest is unethical and may result in sanctions being imposed on me., (Copyright © 2024 The Authors. Published by Elsevier Masson SAS.. All rights reserved.)

Due to its capacity to drive osteoclast differentiation, the receptor activator of nuclear factor kappa-β ligand (RANKL) is believed to exert a pathological influence in periodontitis. However, RANKL was initially identified as an activator of dendritic cells (DCs), expressed by T cells, and exhibits diverse effects on the immune system. Hence, it is probable that RANKL, acting as a bridge between the bone and immune systems, plays a more intricate role in periodontitis. Using ligature-induced periodontitis (LIP), rapid alveolar bone loss was detected that was later halted even though the ligature was still present. This late phase of LIP was also linked with immunosuppressive conditions in the gingiva. Further investigation revealed that the ligature prompted an immediate migration of RANK-expressing Langerhans cells (LCs) and EpCAM + DCs, the antigen-presenting cells (APCs) of the gingival epithelium, to the lymph nodes, followed by an expansion of T regulatory (Treg) cells in the gingiva. Subsequently, the ligatured gingiva was repopulated by monocyte-derived RANK-expressing EpCAM + DCs, while gingival epithelial cells upregulated RANKL expression. Blocking RANKL signaling with monoclonal antibodies significantly reduced the frequencies of Treg cells in the gingiva and prevented gingival immunosuppression. In addition, RANKL signaling facilitated the differentiation of LCs from bone marrow precursors. To further investigate the role of RANKL, we used K14-RANKL mice, in which RANKL is overexpressed by gingival epithelial cells. The elevated RANKL expression shifted the steady-state frequencies of LCs and EpCAM + DCs within the epithelium, favoring LCs over EpCAM + DCs. Following ligature placement, heightened levels of Treg cells were observed in the gingiva of K14-RANKL mice, and alveolar bone loss was significantly reduced. These findings suggest that RANKL-RANK interactions between gingival epithelial cells and APCs are crucial for suppressing gingival inflammation, highlighting a protective immunological role for RANKL in periodontitis that was overlooked due to its osteoclastogenic activity., Competing Interests: Declaration of Conflicting InterestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Fibrosis contributes to tissue repair, but excessive fibrosis disrupts organ function. Alagille syndrome (ALGS, caused by mutations in JAGGED1) results in liver disease and characteristic fibrosis. Here, we show that Jag1 Ndr/Ndr mice, a model for ALGS, recapitulate ALGS-like fibrosis. Single-cell RNA-seq and multi-color flow cytometry of the liver revealed immature hepatocytes and paradoxically low intrahepatic T cell infiltration despite cholestasis in Jag1 Ndr/Ndr mice. Thymic and splenic regulatory T cells (Tregs) were enriched and Jag1 Ndr/Ndr lymphocyte immune and fibrotic capacity was tested with adoptive transfer into Rag1 -/- mice, challenged with dextran sulfate sodium (DSS) or bile duct ligation (BDL). Transplanted Jag1 Ndr/Ndr lymphocytes were less inflammatory with fewer activated T cells than Jag1 +/+ lymphocytes in response to DSS. Cholestasis induced by BDL in Rag1 -/- mice with Jag1 Ndr/Ndr lymphocytes resulted in periportal Treg accumulation and three-fold less periportal fibrosis than in Rag1 -/- mice with Jag1 +/+ lymphocytes. Finally, the Jag1 Ndr/Ndr hepatocyte expression profile and Treg overrepresentation were corroborated in patients' liver samples. Jag1-dependent hepatic and immune defects thus interact to determine the fibrotic process in ALGS., Competing Interests: Disclosure and competing interests statement The authors declare no competing interests. ERA has formerly collaborated with Travere, and Moderna, with no personal remuneration and no conflict of interest., (© 2024. The Author(s).)

Development of protective immune responses relies on a balance between proinflammatory CD4 T helper (Th) cell populations such as Th17 cells and regulatory CD4 T cells (Tregs) that keep immune activation in check. Evidence that interleukin-2-inducible T cell kinase (Itk) regulates this balance supports therapeutic applications for Itk inhibition., Competing Interests: Declaration of interests No interests are declared., (Published by Elsevier Ltd.)

Pre-eclampsia (PE) affects 5-8% of pregnancies and has detrimental effects on maternal-fetal health. PE is characterized by de novo hypertension after 20 wk of gestation and end-organ damage. Systemic inflammatory imbalance has been associated with PE, but its contribution to the pathology is poorly understood. Our objective was to investigate maternal systemic immune changes in early-onset PE (EOPE) and late-onset PE (LOPE) versus uncomplicated pregnancies (control [CTRL]), and their contribution to endothelial activation, hallmark of hypertension. Blood samples were analyzed by flow cytometry, multiplex assay, intracellular cytokine staining, and single-cell RNA sequencing. We performed cocultures between circulating immune cells and HUVECs to assess endothelial activation. We found that EOPE had decreased regulatory T cells (4.64±0.33, p < 0.05) and monocytes (33.92±3.08, p < 0.01), whereas LOPE had decreased regulatory T cells (4.60±0.30, p < 0.05) and Th2 cells (7.50±0.62, p < 0.01) versus CTRL. Compared to CTRL, elevated cytokines/chemokines, and growth factors were observed in LOPE, whereas EOPE primarily showed decreased levels. Using intracellular cytokine staining, we observed more monocytes producing IL-12, TNF-α, and IL-1β (all p < 0.05) in LOPE versus CTRL. At the transcriptomic level, we found differentially expressed genes between EOPE and CTRL, predominantly related to upregulation of immune activation pathways. Lastly, EOPE PBMCs induced heightened endothelial activation in vitro observed by increased ICAM-1 and ET-1 (p < 0.05), whereas LOPE PBMCs required LPS stimulation. Although significant proteomic changes are observed in the LOPE group, the EOPE displayed changes mostly at the transcriptomic levels and could induce endothelial activation in vitro., (Copyright © 2024 by The American Association of Immunologists, Inc.)

Introduction: Myasthenia gravis (MG) is an autoimmune disorder. Microvesicle-derived miRNAs have been implicated in autoimmune diseases. However, the role of microvesicle-derived miR-29a-3p in MG remains poorly understood. This study aimed to investigate the therapeutic effect and mechanism of miR-29a-3p derived from stem cell microvesicles (MVs) on experimental autoimmune myasthenia gravis (EAMG) rats., Methods: EAMG was induced in rats by injection of the subunit of the rat nicotinic anti-acetylcholine receptor (AChR) R97-116 peptide.Besides the control group, EAMG rats were randomly allocated into the EAMG model group, MV group, MV-NC-agomir group, and MV- miR-29a-3p-agomir group., Results: Our results found that BMSCs-MV promoted miR-29a-3p expression in gastrocnemius of EAMG rats. Bone marrow mesenchymal stem cells (BMSCs) derived microvesicle miR-29a-3p improved the hanging ability and swimming time of EMGA rats and weakened the degree of muscle fiber atrophy. Furthermore, microvesicles from miR-29a-3p overexpressing BMSCs reduced the content of AchR-Ab in the serum of EAMG rats. BMSC-derived microvesicle miR-29a-3p further suppressed the expression of IFN-γ and enhanced the IL-4 and IL-10 in the serum of EAMG rats by restoring the Th17/Treg cells balance., Discussion: BMSCs-derived microvesicle miR-29a-3p improved the stability of rat myasthenia gravis by regulating Treg/Th17 cells. It may be an effective treatment for MG.

Follicular helper (Tfh), peripheral helper (Tph), and regulatory (Treg) T cells are involved in myasthenia gravis (MG) pathogenesis, an autoimmune disorder arising from autoantibodies targeting neuromuscular junction proteins. This study explores the impact of low-dose IL-2 on Tfh, Tph, and Treg cells in vitro in MG. Acetylcholine-receptor antibody-positive MG (AChR-MG), muscle-specific kinase antibody-positive MG (MuSK-MG) patients, and healthy controls (HC) were studied. Blood cells were cultured with/without IL-2 and compared by the ratios of IL-2 stimulated/unstimulated cultures. In both AChR-MG and MuSK-MG patients, CD25 + FoxP3 + Tregs were lower, while CXCR5 + PD-1 + or ICOS + Tfh and CXCR5 - PD-1 + or ICOS + Tph cells were higher compared with HC. Among the MG group, the FoxP3 + Treg cells in AChR-MG patients were even lower compared with MuSK-MG patients. In vitro IL-2 stimulation increased Tregs in all groups while decreasing PD-1 + /ICOS + Tfh and PD-1 + /ICOS + Tph populations. The fold-increase ratio of Tregs and the fold-decrease ratio of PD-1 + or ICOS + Tfh and ICOS + Tph cells in AChR-MG and MuSK-MG patients were greater than in HCs. Low-dose IL-2 treatment may balance Tfh, Tph, and Treg cells in MG patients, offering a potential opportunity for disease modulation., (© 2024 The Author(s). European Journal of Immunology published by Wiley‐VCH GmbH.)

Antiprogrammed death ligand 1 (PD-L1) therapy is a leading immunotherapy, but only some patients with solid cancers benefit. Overwhelming evidence has revealed that PD-L1 is expressed on various immune cells in the tumor microenvironment (TME), including macrophages, dendritic cells, and regulatory T cells, modulating tumor immunity and influencing tumor progression. PD-L1 can also be located on tumor cell membranes as well as in exosomes and cytoplasm. Accordingly, the dynamic expression and various forms of PD-L1 might explain the therapy's limited efficacy and resistance. Herein a systematic summary of the expression of PD-L1 on different immune cells and their regulatory mechanisms is provided to offer a solid foundation for future studies., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

In this article, we discuss new findings which suggest that type I regulatory T (Tr1) cells can interfere with cancer vaccine efficacy in mice by exerting strong regulatory control over antitumor immune responses., (© 2024 the Australian and New Zealand Society for Immunology, Inc.)

Alopecia areata is a common autoimmune disorder characterized by non-scarring hair loss on the scalp or other hair-bearing surface. In recent years, Janus kinase (JAK) inhibitors have shown promise in the treatment of alopecia areata by disrupting the signaling pathways involved in immune-mediated hair follicle damage. However, some patients with alopecia areata exhibit insufficient responses to JAK inhibitors. This review aims to explore the predictive factors for poor responses to JAK inhibitors in patients with alopecia areata and to discuss alternative treatment strategies in such cases. Patients with a longer duration of the current episode and higher baseline severity are at an increased risk of inadequate JAK inhibitor responses. Oral administration rather than topical application, and extended treatment durations, correlate with a favorable response. Notably, the poor response to JAK inhibitors in alopecia areata may be related to the amount and functional depletion of regulatory T cells resulting from an augmented T helper-2-type immune response. For patients with poor responses to JAK inhibitors, treatment adjustments may include increasing the dosage, extending the treatment duration, combination therapies, or switching to alternative JAK inhibitors. For patients with atopic comorbidities or psychological problems, it is important to select corresponding treatment options to optimize patient outcomes. Further research is needed to establish more reliable predictors and improve overall patient care., (© 2024. The Author(s), under exclusive licence to Springer Nature Switzerland AG.)