The biology of interleukin-2

The role of cytokines in shaping the future of Cancer immunotherapy

As essential immune system regulators, cytokines are essential for modulating both innate and adaptive immunological responses. They have become important tools in cancer immunotherapy, improving the immune system's capacity to identify and destroy tumor cells. This article examines the background, workings, and therapeutic uses of cytokines, such as interleukins, interferons, and granulocyte-macropHage colony-stimulating factors, in the management of cancer. It examines the many ways that cytokines affect immune cell activation, signaling pathways, tumor development, metastasis, and prognosis by modifying the tumor microenvironment. Despite the limited effectiveness of cytokine-based monotherapy, recent developments have concentrated on new fusion molecules such as immunocytokines, cytokine delivery improvements, and combination techniques to maximize treatment efficacy while reducing adverse effects. Current FDA-approved cytokine therapeutics and clinical trial results are also included in this study, which offers insights into how cytokines might be used with other therapies including checkpoint inhibitors, chemotherapy, and radiation therapy to address cancer treatment obstacles. This study addresses the intricacies of cytokine interactions in the tumor microenvironment, highlighting the possibility for innovative treatment methods and suggesting fresh techniques for enhancing cytokine-based immunotherapies. PEGylation, viral vector-mediated cytokine gene transfer, antibody-cytokine fusion proteins (immunocytokines), and other innovative cytokine delivery techniques are among the novelties of this work, which focuses on the most recent developments in cytokine-based immunotherapy. Additionally, the study offers a thorough examination of the little-reviewed topic of cytokine usage in conjunction with other treatment techniques. It also discusses the most recent clinical studies and FDA-approved therapies, providing a modern perspective on the developing field of cancer immunotherapy and suggesting creative ways to improve treatment effectiveness while lowering toxicity. BACKGROUND: Cytokines are crucial in cancer immunotherapy for regulating immune responses and modifying the tumor microenvironment (TME). However, challenges with efficacy and safety have driven research into advanced delivery methods and combination therapies to enhance their therapeutic potential.

Regulatory T cell memory: implications for malaria

Regulatory T cells (Tregs) can persist as memory cells (mTregs) in both infectious and non-infectious settings. However, their functional behavior, phenotypic stability, and suppressive properties upon antigen re-exposure remain poorly understood. Emerging evidence suggests that mTregs exhibit enhanced proliferation and suppressive capacity upon re-encountering the same antigen, a feature that may be critical in recurrent infections such as malaria. In malaria, Tregs are known to modulate immune responses and influence acute disease outcomes, suggesting that mTreg recall may play a significant role in long-term immunity. This review explores the biology of Treg memory, with a focus on malaria, and examines the immunological implications of maintaining a suppressive mTreg population in malaria immunity.

A glimpse into the application of the immunomodulatory effect of IL-2 in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease, which is mainly caused by the imbalance of immune cells. Current treatment regimens predominately rely on corticosteroids and immunosuppressive agents, accompanied by various side effects. Interleukin-2 (IL-2) is deemed an important cytokine for innate immune cells and adaptive immune cells, especially for the promotion of Treg cells. By combining IL-2/IL-2R system with engineered T cell-based immunotherapies to enhance the therapeutic efficacy of engineered T cells shows its potential in autoimmune diseases. But the pleiotropy of IL-2 may cause simultaneous stimulation and systemic toxicity, limiting its therapeutic use. There is a growing focus on using IL-2 in combination strategies for synergistic immune enhancement. In this article, we review the IL-2/IL-2R signaling, including IL-2 dependent signaling and IL-2 independent signaling, and discuss its functions in regulation of different immune cells. In addition, we summarize major clinical application of low-dose IL-2 treatment in SLE with or without other agents, such as rapamycin, tocilizumab and rituximab, present the IL-2 variants and fusion proteins designed for SLE, and highlight the future trends for research on these cytokine-based immunotherapies. It will help to design further optimized IL-2-based therapy for SLE.

Treatment with cyclosporine attenuates the inflammatory process and severity of bisphosphonate-induced osteonecrosis of the jaws in rats

INTRODUCTION

Osteonecrosis usually occurs with necrotic bone exposure in the mandible asymptomatically for long periods but can evolve to present pain, fistula, odor, bleeding, and suppuration.

OBJECTIVE

To evaluate the influence of cyclosporine treatment and its influence on osteonecrosis in a rat model.

METHODS

The animals were randomly divided into 05 groups (n = 8/group). The negative control group (SAL), positive control group treated with zoledronic acid (ZA + SAL), and test groups were treated with cyclosporine A (CsA) at 5, 2.5, and 1.25 mg/kg and treated with ZA. The left lower second molars were extracted. The animals were euthanized 1 month after tooth extraction. Digital radiographs, histological slides, and immunoexpression of IL-2, IL-6, TNF-α, PPAR-γ, c-Fos, c-Jun, FoxP3, and INF-γ were analyzed. Western blot assays were performed to investigate the expression of RORyT. In addition, hematological analysis, body mass variation, and femur mechanical tests were performed.

RESULTS

Radiographs showed that in the groups treated with ZA, there was an increase in the radiolucent area suggestive of osteonecrosis, and treatment with cyclosporine did not reduce this parameter (p < 0.001). In the western blot analysis, animals treated with ZA showed increased expression of RORyT (1.887 ± 0.114) compared to the saline group (0.799 ± 0.107), and treatment with the highest dose of cyclosporine (0.652 ± 0.070) reduced this expression (p < 0.001).

DISCUSSION

Studies have observed bone health in animals treated with CsA. Treatment with this immunosuppressant showed a bone-protective effect of CsA, which corroborates our findings.

CONCLUSION

Treatment with CsA reduced the immunoexpression of pro-inflammatory cytokines such as IL-2 and TNF-α and decreased the expression of RORyT.

Enhancing the Anticancer Activity of a Carcinoma-Directed Peptide-HLA-I Fusion Protein by Armoring with Mutein IFNα

Previously, we reported on the peptide-HLA-I fusion protein EpCAM-ReTARGTPR, which allows us to redirect the cytotoxic activity of pre-existing anti-CMV CD8pos T cell immunity to selectively eliminate EpCAMpos cancer cells. EpCAM-ReTARGTPR consists of the CMV pp65-derived peptide TPRVTGGGAM (TPR) fused in tandem with a soluble HLA-B*07:02/β2-microglobulin (β2M) molecule and an EpCAM-directed Fab antibody fragment. To further enhance its anticancer activity, we equipped EpCAM-ReTARGTPR with the immune-potentiating cytokine muteins IL2(H16A,F42A) and IFNαR149A, respectively. Both cytokines are engineered to have attenuated affinity for their respective cytokine receptors. Compared to EpCAM-ReTARGTPR, in vitro treatment of EpCAMpos carcinoma cell lines with EpCAM-ReTARGTPRvIL2 for 24 h increased the cytotoxic activity of PBMCs containing low levels of TPR-specific CD8pos T cells by ~15%, whereas EpCAM-ReTARGTPRIFNαR149A induced an increase of ~50%. Moreover, treatment for 120 h with EpCAM-ReTARGTPRIFNαR149A inhibited the proliferative capacity of the cancer cell lines OvCAR3 and PC3M by ~91% without compromising the viability of the TPR-specific CD8pos T cells and increased their capacity for IFNγ secretion. Importantly, EpCAM-ReTARGTPRIFNαR149A potently induced the elimination of primary EpCAMpos refractory carcinoma cells from a Merkel cell carcinoma (MCC) patient. Taken together, the armoring of the carcinoma-directed peptide-HLA-I fusion protein EpCAM-ReTARGTPR with IFNαR149A potently enhanced the efficacy of pre-existing anti-CMV CD8pos T cell immunity to selectively eliminate EpCAMpos cancer cells.

Resolution of inflammation during rheumatoid arthritis

Rheumatoid arthritis (RA) is a chronic autoimmune disease that causes synovial joint inflammation as well as bone destruction and erosion, typically characterized by joint pain, swelling, and stiffness, with complications and persistent pain after remission posing a significant health burden for RA patients. The etiology of RA has not yet been fully elucidated, but a large number of studies have shown that the initiation of inflammation in RA is closely related to T-cell activation, the production of a variety of pro-inflammatory cytokines, macrophage M1/M2 imbalance, homeostatic imbalance of the intestinal flora, fibroblast-like synoviocytes (FLSs) and synovial tissue macrophages (STMs) in the synovial lumen of joints that exhibit an aggressive phenotype. While the resolution of RA is less discussed, therefore, we provided a systematic review of the relevant remission mechanisms including blocking T cell activation, regulating macrophage polarization status, modulating the signaling pathway of FLSs, modulating the subpopulation of STMs, and inhibiting the relevant inflammatory factors, as well as the probable causes of persistent arthritis pain after the remission of RA and its pain management methods. Achieving resolution in RA is crucial for improving the quality of life and long-term prognosis of patients. Thus, understanding these mechanisms provide novel potential for further drug development and treatment of RA.

Dynamic functional assessment of T cells reveals an early suppression correlating with adverse outcome in polytraumatized patients

Introduction

Most trauma patients require intensive care treatment and are susceptible to developing persistent inflammation and immunosuppression, potentially leading to multi organ dysfunction syndrome (MODS) and dependence on long term care facilities. T cells undergo changes in numbers and function post trauma. T cell dysfunction in polytraumatized patients was characterized using functional immunomonitoring to predict individual clinical outcome. Moreover, the potential to reverse T cell dysfunction using Interleukin (IL)-7 was examined.

Methods

Blood samples were drawn from healthy individuals and prospectively enrolled polytrauma patients (Injury Severity Score ≥ 18) on admission, 8, 24 and 48 hours, 5 and 10 days after. CD3/28-stimulated cytokine production of T cells in whole blood was assessed via Enzyme Linked Immuno Spot (ELISpot). T cell subsets were quantified via counting and flow cytometry. Unfavorable physical performative outcome was defined as death or new functional disability necessitating long term care. Secondary outcomes were the development of MODS and in-hospital mortality. IL-7 was added ex vivo to test reversibility of cytokine disturbances.

Results

34 patients were enrolled. The different outcome groups showed no difference in injury severity. Patients with favorable physical performative outcome revealed higher functional T cell specific Interferon γ (IFN-γ) and IL-17 (8 hours) and lower IL-10 production (day 5) and higher CD8 T cell concentrations. Patients without MODS development showed a higher IFN-γ (day 10), higher IL-2 (8 hours) and higher IL-17 production (admission, day 5). There were no differences regarding in-hospital mortality. Systemic blood IFN-γ, IL-2 and IL-10 concentrations only correlated with MODS (24 hours). Systemic CD8 T cell numbers correlated with functional IFN-γ production. Whole blood stimulation with IL-7 increased functional T cell IFN-γ release.

Discussion

Our study reveals an early characteristic overall T cell dysfunction of pro-inflammatory (IFN-γ, IL-2, IL-17) and immunosuppressive (IL-10) subtypes in polytraumatized patients. Our data indicates that rather the functional capacity of T cells to release cytokines, but not systemic cytokine concentrations can be used to predict outcome post trauma. We assume that the early stimulation of pro- and anti-inflammatory T cells benefits polytraumatized patients. Potentiation of functional IFN-γ release might be achieved by IL-7 administration.

Pneumocystis Jirovecii Pneumonia: The Potential of KEX1, MSG1, and MSG2 as Key Antigens in Cytokine Release Assays

Background/Objectives:Pneumocystis jirovecii pneumonia (PJP) is the most frequently diagnosed AIDS-defining illness in Europe, with especially high mortality in HIV-negative patients caused by delayed diagnosis and low awareness. This study aims to evaluate cytokine release assays (CRA) to facilitate a less invasive and resource-efficient PJP specific diagnostic test. We focus on the P. jirovecii antigens Kexin 1 (KEX1), MSG1, and MSG2, which were identified in prior studies as immunologically relevant. Methods: Whole blood samples from 50 participants-22 healthy individuals and 28 immunocompromised individuals, including 8 with proven PJP-were stimulated in vitro with full-length and partial KEX1, MSG1, MSG2, and a combination of all three antigens (PJ-MIX). Following 24 h incubation at 37 °C, cytokine levels of IL-2, IFN-γ, IL-17A, and IL-17F were measured. Results: Stimulation with full-length KEX1, MSG1, MSG2, and PJ-MIX antigens induced higher IL-2 concentrations in the healthy control group compared to the groups IL-2 baseline levels and to the group of proven PJP cases. Similarly, stimulation with full-length KEX1, MSG1, and PJ-MIX elevated IFN-γ levels in the healthy control group compared to baseline IFN-γ levels. Conclusions: Our findings highlight the potential of IL-2 and IFN-γ release following stimulation with PJ antigens, with PJ-MIX eliciting the strongest and most significant responses, suggesting a cumulative antigen effect. This pilot study establishes a foundation for a PJP-specific CRA, deepening our knowledge of T-cell immunity against PJP. Clinically, such a test could, among other applications, evaluate at-risk patients who should receive prophylaxis and may consequently reduce PJP-related morbidity and mortality.

The Lasting Impact of IL-2: Approaching 50 Years of Advancing Immune Tolerance, Cancer Immunotherapies, and Autoimmune Diseases

BACKGROUND

The discovery of interleukin-2 (IL-2) and its receptor (IL-2R) almost 50 years ago revolutionized immunology, marking a pivotal moment in understanding T cell biology and immune regulation. Initially identified as a T cell growth factor, IL-2 unveiled critical insights into cytokine-mediated immune cell proliferation and differentiation.

METHODS

This review highlighted the characterization of IL-2R as a multi-chain receptor complex set a precedent for decoding cytokine receptor signaling. The unique interplay between IL-2 and its high-affinity receptor component, IL-2Rα, epitomizes the principle of specificity and efficiency in cytokine signaling, enabling precise immune modulation. Regulatory T cells (Tregs) exploit IL-2Rα high affinity to outcompete effector T cells for IL-2, ensuring immune tolerance and preventing autoimmunity.

RESULTS

Despite its foundational role in immune homeostasis, leveraging IL-2 for therapeutic purposes has proven challenging.

CONCLUSION

IL-2-based therapies hold transformative potential in autoimmunity, cancer immunology, and transplantation, yet they remain elusive due to the complex balance between immunostimulatory and immunosuppressive effects. This review explores the milestones in IL-2 biology, its dualistic functions, and the ongoing quest to harness its therapeutic promise.

Directed disruption of IL2 aggregation and receptor binding sites produces designer biologics with enhanced specificity and improved production capacity

The pleotropic nature of interleukin-2 (IL2) has allowed it to be used as both a pro-inflammatory and anti-inflammatory therapeutic agent, through promotion of regulatory T cell (Treg) responses via the trimeric IL2RABG receptor or promotion of CD8 T cell responses via the dimeric IL2RBG receptor, respectively. However, the utility of IL2 as a treatment is limited by this same pleiotropy, and protein engineering to bias specificity towards either Treg or CD8 T cell lineage often requires a trade-off in protein production or total bioactivity. Here we use SolubiS and dTANGO, computational algorithm-based methods, to predict mutations within the IL2 structure to improve protein production yield in muteins with altered cellular selectivity, to generate combined muteins with elevated therapeutic potential. The design and testing process identified the V106R (murine) / V91R (human) mutation as a Treg-enhancing mutein, creating a cation repulsion to inhibit primary binding to IL2RB, with a post-IL2RA confirmational shift enabling secondary IL2RB binding, and hence allowing the trimeric receptor complex to form. In human IL2, additional N90R T131R aggregation-protecting mutations could improve protein yield of the V91R mutation. The approach also generated novel CD8 T cell-promoting mutations. Y59K created a cation-cation repulsion with IL2RA, while Q30W enhanced CD8 T cell activity through potential π-stacking enhancing binding to IL2RB, with the combination highly stimulatory for CD8 T cells. For human IL2, Y45K (homolog to murine Y59K) coupled with E62K prevented IL2RA binding, however it required the aggregation-protecting mutations of N90R T131R to rescue production. These muteins, designed with both cellular specificity and protein production features, have potential as both biological tools and therapeutics.

Immune memory in hepatitis E virus: a comparative study of natural infection and vaccination in a nursing home population

Immune memory is crucial for preventing hepatitis E virus (HEV) infection. Our study aims to investigate immunological memory characteristics and differences between vaccination and natural HEV infection, taking into account that both can induce immune memory. We recruited 60 HEV-infected patients, 58 contingency HEV-vaccinated individuals and 4 controls from an outbreak of hepatitis E in a nursing home between June and August 2023. Multicolor flow cytometry, ELISA, and quantitative polymerase chain reaction (qPCR) were employed to detect memory T-cell expression profiles, HEV-specific antibodies and cytokine expression. We observed that the level of HEV-specific IgM in acute jaundiced hepatitis E patients was greater than that in non-jaundiced patients (8.37 ± 1.27 vs. 4.27 ± 0.81, P < 0.05). No significant differences were detected in the HEV-specific IgG and memory T cell expression profiles among the different severities of hepatitis E. The percentage of CD8+ TEM at 6 months after recovery was significantly greater than that in acute jaundice patients (1.60% ± 0.30% vs. 1.15% ± 0.35%, P < 0.05). Compared with natural infection, three-dose vaccination increased the level of HEV-specific IgG (14.97 ± 0.21 vs. 12.75 ± 0.37, P < 0.05), IL-7 and IL-15 (28.50 ± 3.82 vs. 23.32 ± 6.37, 608.60 ± 143.30 vs. 257.50 ± 69.87, P < 0.05). Natural infection could effectively establish immune memory. During convalescence, infection severity impacted only HEV-specific IgM, while HEV-specific IgG and memory T-cell expression profiles were not affected. Compared with natural infection, three-dose vaccination results in equal effective humoral immune memory and weaker cellular immune memory with minimal side effects.

Pan T cells, Helper T cells, and Regulatory T cells are Associated with Negative Symptoms in Persons with Anti-Gliadin Antibody Positive Schizophrenia and Related Disorders

Background

About one in three persons with a schizophrenia related disorder (SRD) have elevated anti-gliadin IgG antibodies (AGA). This AGA positive (AGA+) subgroup of SRD clinically has a higher burden of negative symptoms and are symptoms associated with high functional impairments with a lack of effective therapeutics. Alterations in T cells have been demonstrated in SRD, and we have previously shown regulatory T cells (Tregs) are increased and correlate with fewer negative symptoms in persons with SRD compared with healthy controls.

Methods

To further elucidate the role of the immune system in AGA+ SRD pathology, we investigated the relationship of T cells and negative symptoms in 26 medicated and clinically stable persons with SRD. Participants had blood drawn; AGA-IgG measured by ELISA (AGA positive defined as ≥20 U); had flow cytometry performed to quantify proportions of pan T cells (CD3+), helper T cells (CD3+CD4+), Tregs (CD3+CD4+CD25+Foxp3+), and activated Tregs (aTregs) (CD3+CD4+CD25+Foxp3+RA-); had serum cytokines measured; and completed the Scale for the Assessment of Negative Symptoms (SANS) to measure negative symptoms.

Results

46% of persons with SRD in this study were AGA+ and, in this group specifically, pan-T cells were correlated with worse SANS total, anhedonia, alogia, and avolition (p<0.05), while helper T cells and Tregs were correlated with less negative symptoms (respectively, SANS total and alogia; SANS total, anhedonia, alogia; P<0.05). AGA+ persons with SRD also had several elevated serum cytokines, corresponding with a broadly pro-inflammatory phenotype.

Conclusions

These hypothesis-generating findings highlight T cell dysfunction in AGA+ positive SRD, suggesting Tregs protecting against negative symptom severity but also an unidentified other T cell population to possibly be driving negative symptom severity.

Leukemia-Derived Dendritic Cells Induce Anti-Leukemic Effects Ex Vivo in AML Independently of Patients' Clinical and Biological Features

New therapies are highly needed to stabilize remission in patients with acute myeloid leukemia (AML). This study investigates the value of dendritic cells derived from leukemic blasts (DCleu) to enhance anti-leukemic immunity after T-cell-enriched mixed lymphocyte cultures (MLCs). We correlated induced anti-leukemic activity with patient data, including biological, clinical and prognostic factors. Additionally, we correlated the frequencies of DC/DCleu and leukemic-specific T cells with the achieved anti-leukemic activity after MLC. We show that mature DC/DCleu can be generated using the immunomodulating Kit-M, which contains granulocyte-macrophage colony-stimulating-factor (GM-CSF) and prostaglandin E1 (PGE1), without inducing blast proliferation from leukemic whole blood (WB) samples. Activated leukemia-specific immune and memory cells increased after MLC with Kit-M-pretreated WB, leading to improved blast lysis. Enhanced anti-leukemic activity positively correlated with the frequencies of generated DC/DCleu, proliferating leukemic-specific T cells and memory T cells, but not with leukemic blast counts, hemoglobin levels or platelet counts at diagnosis. No correlation was found between improved blast lysis and patients' prognostic data, including age, gender, ELN risk groups, disease stage and response to induction chemotherapy. These findings underscore the potential of DC/DCleu to evoke robust immune responses and potential immunological memory against AML. Overall, this innovative approach could pave the way for the development of improved immunotherapeutic strategies that function in vivo.

Exploring Advances in Natural Plant Molecules for Allergic Rhinitis Immunomodulation in Vivo and in Vitro

Allergic rhinitis (AR) is a prevalent allergic disease that imposes significant economic burdens and life pressures on individuals, families, and society, particularly in the context of accelerating globalization and increasing pathogenic factors. Current clinical therapies for AR include antihistamines, glucocorticoids administered via various routes, leukotriene receptor antagonists, immunotherapy, and several decongestants. These treatments have demonstrated efficacy in alleviating clinical symptoms and pathological states. However, with the growing awareness of AR and rising expectations for improvements in quality of life, these treatments have become associated with a higher incidence of side effects and an elevated risk of drug resistance. Furthermore, the development of AR is intricately associated with dysregulation of the immune system, yet the underlying pathogenetic mechanisms remain incompletely understood. In contrast, widely available natural plant molecules offer multiple targeting pathways that uniquely modify the typical pathophysiology of AR through immunomodulatory processes. This review presents a comprehensive analysis of both in vivo and in vitro studies on natural plant molecules that modulate immunity for treating AR. Additionally, we examine their specific mechanisms of action in animal models to provide new insights for developing safe and effective targeted therapies while guiding experimental and clinical applications against AR.

Based on the immune system: the role of the IL-2 family in pancreatic disease

The IL-2 family, consisting of IL-2, IL-4, IL-7, IL-9, IL-15 and IL-21, is a key regulator of the immune response. As an important endocrine and digestive organ, the function of the pancreas is regulated by the immune system. Studies have shown that each cytokine of the IL-2 family influences the occurrence and development of pancreatic diseases by participating in the regulation of the immune system. In this paper, we review the structural and functional characteristics of IL-2 family members, focus on their molecular mechanisms in pancreatic diseases including acute pancreatitis, chronic pancreatitis and pancreatic cancer, and highlight the importance of the related proteins in the regulation of immune response and disease progression, which will provide valuable insights for new biomarkers in pancreatic diseases, early diagnosis of the diseases, assessment of the disease severity, and development of new therapeutic regimens. The insights of the study are summarized in the following sections.

Efficacy of Anti-Cancer Immune Responses Elicited Using Tumor-Targeted IL-2 Cytokine and Its Derivatives in Combined Preclinical Therapies

Effective cancer therapies must address the tumor microenvironment (TME), a complex network of tumor cells and stromal components, including endothelial, immune, and mesenchymal cells. Durable outcomes require targeting both tumor cells and the TME while minimizing systemic toxicity. Interleukin-2 (IL-2)-based therapies have shown efficacy in cancers such as metastatic melanoma and renal cell carcinoma but are limited by severe side effects. Innovative IL-2-based immunotherapeutic approaches include immunotoxins, such as antibody-drug conjugates, immunocytokines, and antibody-cytokine fusion proteins that enhance tumor-specific delivery. These strategies activate cytotoxic CD8+ T lymphocytes and natural killer (NK) cells, eliciting a potent Th1-mediated anti-tumor response. Modified IL-2 variants with reduced Treg cell activity further improve specificity and reduce immunosuppression. Additionally, IL-2 conjugates with peptides or anti-angiogenic agents offer improved therapeutic profiles. Combining IL-2-based therapies with immune checkpoint inhibitors (ICIs), anti-angiogenic agents, or radiotherapy has demonstrated synergistic potential. Preclinical and clinical studies highlight reduced toxicity and enhanced anti-tumor efficacy, overcoming TME-driven immune suppression. These approaches mitigate the limitations of high-dose soluble IL-2 therapy, promoting immune activation and minimizing adverse effects. This review critically explores advances in IL-2-based therapies, focusing on immunotoxins, immunocytokines, and IL-2 derivatives. Emphasis is placed on their role in combination strategies, showcasing their potential to target the TME and improve clinical outcomes effectively. Also, the use of IL-2 immunocytokines in "in situ" vaccination to relieve the immunosuppression of the TME is discussed.

Effects of chemokine-binding protein in visceral ovine aphthae on immune regulation response

ORFV of the family poxvirus，which produces a pustular dermatitis both in humans and animals.,Previous studies have found an fatal case caused by the infection of ORFV in the viscera. However, the mechanisms of ORFV how to infect the viscera remain unknown. Our sequencing results revealed that the CBP of the visceral infection strain lacked a 24-base pair segment at position 217 comparison to the oral infection strain. Subsequently, we successfully packaged the recombinant adenoviruses pAd-CBP-K and pAd-CBP-N in HEK-293A cells and carried it to infect lymphocytes. RT-PCR analysis showed that the CBP protein was expressed in lymphocytes, and pAd-CBP-N group exhibited a significantly higher CBP expression level compared to the pAd-CBP-K group. At 4, 8, and 12 hours post-infection, both pAd-CBP-K and pAd-CBP-N were found to downregulate the expression of MIP-1 and CCL-5 in the supernatant of lymphocytes. However, the expression of IL-2, IL-6, IL-8, IL-12, INF-γ, and TNF-α showed a significant up-regulation. Furthermore, the inflammatory factors relative expression levels of IL-2, IL-6, IL-8, IL-8, IL-12, IFN-γ and TNF-α were significantly up-regulated in the both group. Interestingly, a significant increase in the expression of IL-6, IL-8 and TNF-α were detected in the pAd-CBP-N group at both 8 and 12 hours compared to pAd-CBP-N. Taken together, these findings showed that CBP can regulate the expression of free chemokines and activate the expression of inflammatory factors, and provide a basis for follow-up research.

The IL-2 SYNTHORIN molecule promotes functionally adapted Tregs in a preclinical model of type 1 diabetes

Deficits in IL-2 signaling can precipitate autoimmunity by altering the function and survival of FoxP3+ regulatory T cells (Tregs) while high concentrations of IL-2 fuel inflammatory responses. Recently, we showed that the non-beta IL-2 SYNTHORIN molecule SAR444336 (SAR'336) can bypass the induction of autoimmune and inflammatory responses by increasing its reliance on IL-2 receptor α chain subunit (CD25) to provide a bona fide IL-2 signal selectively to Tregs, making it an attractive approach for the control of autoimmunity. In this report, we further demonstrate that SAR'336 can support non-beta IL-2 signaling in murine Tregs and limit NK and CD8+ T cells' proliferation and function. Using a murine model of spontaneous type 1 diabetes, we showed that the administration of SAR'336 slows the development of disease in mice by decreasing the degree of insulitis through the expansion of antigen-specific Tregs over Th1 cells in pancreatic islets. Specifically, SAR'336 promoted the differentiation of IL-33-responsive (ST2+), IL-10-producing GATA3+ Tregs over other Treg subsets in the pancreas, demonstrating the ability of this molecule to further orchestrate Treg adaptation. These results offer insight into the capacity of SAR'336 to generate highly specialized, tissue-localized Tregs that promote restoration of homeostasis during ongoing autoimmune disease.

Systematic exploration of the molecular characteristics of CD8+ T cells to predict the response to immunotherapy and the prognosis of patients with colon adenocarcinoma

Background

Recently, immunotherapy has been recognized as an innovative treatment with great potential for patients with colon adenocarcinoma (COAD). Although the relationships between immune cells and immune substances are intricate and still unclear, some immune cells and substances could be considered prognostic factors for predicting therapeutic efficacy. To understand the genomic signatures of COAD related to CD8+ T cells that could predict the prognosis of patients receiving immunotherapy and to discover new therapeutic targets, we conducted this study.

Methods

Data were gathered from the TCGA and GEO databases to assess the molecular features of CD8+ T cells. We developed a CD8+ T-cell score (CD8S) to quantify the population of CD8+ T cells in each COAD patient. A thorough analysis of multilevel data was conducted to evaluate overall survival (OS), biological functions, immunological profiles, drug sensitivity, and responses to immunotherapy between the two groups defined by CD8S. Additionally, a series of in vitro experiments were executed to validate the reliability of the signatures associated with CD8+ T cells.

Results

CD8S has been shown to be a reliable prognostic factor for COAD according to different patient and subgroup analyses. Through in vitro experiments, we suggested that TSPYL2 may act as an oncogene in COAD. Through functional analysis, a high expression of genes linked to the cell cycle, cytoskeleton, cell adhesion, and various cancer-related pathways was observed in the high CD8S group, which aids in tumor invasion. Moreover, immune analysis reflected immunosuppression in patients with high CD8S. Patients in the low CD8S group were more sensitive to chemotherapy, targeted drugs, and immunotherapy due to higher genetic variants.

Conclusion

To better understand the biological characteristics and prognostic significance of CD8+ T cells in immunotherapy for COAD, we thoroughly examined the molecular properties of CD8+ T cells in COAD and developed a CD8+ T-cell model.

Case report: Low-dose interleukin-2: a treatment of bullous pemphigoid with predominantly perifollicular blistering caused by PD-1/PD-L1 inhibitor

Objectives

This study aimed to evaluate the efficacy of low-dose interleukin (IL-2) treatment for bullous pemphigoid (BP) caused by anti-programmed cell death protein 1/ligand 1 (PD-1/PD-L1) inhibitors.

Methods

Low-dose IL-2 treatment was standardized for BP. The Bullous Pemphigoid Disease Area Index (BPDAI), 5D-Itch Scale (5D-IS), and Dermatology Life Quality Index (DLQI) were recorded before and after treatment, and hexachromatic lymphocytes, regulatory T cells (Treg cells), and cytokines were measured.

Results

A significant decline in the BPDAI score, 5D-IS, and DLQI score was observed following treatment. The count of B-cells, CD4+ T-cells, CD8+ T-cells, Treg cells, and the levels of cytokines (IL-4, -8, and -10) were significantly downregulated in comparison to baseline measurements.

Conclusion

Low-dose IL-2 could be an effective therapeutic choice for treating BP caused by PD-1/PD-L1 inhibitors.

IL-2-mediated hepatotoxicity: knowledge gap identification based on the irAOP concept

Drug-induced hepatotoxicity constitutes a major reason for non-approval and post-marketing withdrawal of pharmaceuticals. In many cases, preclinical models lack predictive capacity for hepatic damage in humans. A vital concern is the integration of immune system effects in preclinical safety assessment. The immune-related Adverse Outcome Pathway (irAOP) approach, which is applied within the Immune Safety Avatar (imSAVAR) consortium, presents a novel method to understand and predict immune-mediated adverse events elicited by pharmaceuticals and thus targets this issue. It aims to dissect the molecular mechanisms involved and identify key players in drug-induced side effects. As irAOPs are still in their infancy, there is a need for a model irAOP to validate the suitability of this tool. For this purpose, we developed a hepatotoxicity-based model irAOP for recombinant human IL-2 (aldesleukin). Besides producing durable therapeutic responses against renal cell carcinoma and metastatic melanoma, the boosted immune activation upon IL-2 treatment elicits liver damage. The availability of extensive data regarding IL-2 allows both the generation of a comprehensive putative irAOP and to validate the predictability of the irAOP with clinical data. Moreover, IL-2, as one of the first cancer immunotherapeutics on the market, is a blueprint for various biological and novel treatment regimens that are under investigation today. This review provides a guideline for further irAOP-directed research in immune-mediated hepatotoxicity.

Gluten-Dependent Activation of CD4+ T Cells by MHC Class II-Expressing Epithelium

BACKGROUND & AIMS

Intestinal epithelial cell (IEC) damage is a hallmark of celiac disease (CeD); however, its role in gluten-dependent T-cell activation is unknown. We investigated IEC-gluten-T-cell interactions in organoid monolayers expressing human major histocompatibility complex class II (HLA-DQ2.5), which facilitates gluten antigen recognition by CD4+ T cells in CeD.

METHODS

Epithelial major histocompatibility complex class II (MHCII) was determined in active and treated CeD, and in nonimmunized and gluten-immunized DR3-DQ2.5 transgenic mice, lacking mouse MHCII molecules. Organoid monolayers from DR3-DQ2.5 mice were treated with or without interferon (IFN)-γ, and MHCII expression was evaluated by flow cytometry. Organoid monolayers and CD4+ T-cell co-cultures were incubated with gluten, predigested, or not by elastase-producing Pseudomonas aeruginosa or its lasB mutant. T-cell function was assessed based on proliferation, expression of activation markers, and cytokine release in the co-culture supernatants.

RESULTS

Patients with active CeD and gluten-immunized DR3-DQ2.5 mice demonstrated epithelial MHCII expression. Organoid monolayers derived from gluten-immunized DR3-DQ2.5 mice expressed MHCII, which was upregulated by IFN-γ. In organoid monolayer T-cell co-cultures, gluten increased the proliferation of CD4+ T cells, expression of T-cell activation markers, and the release of interleukin-2, IFN-γ, and interleukin-15 in co-culture supernatants. Gluten metabolized by P aeruginosa, but not the lasB mutant, enhanced CD4+ T-cell proliferation and activation.

CONCLUSIONS

Gluten antigens are efficiently presented by MHCII-expressing IECs, resulting in the activation of gluten-specific CD4+ T cells, which is enhanced by gluten predigestion with microbial elastase. Therapeutics directed at IECs may offer a novel approach for modulating both adaptive and innate immunity in patients with CeD.

Integrating chemokines and machine learning algorithms for diagnosis and bleeding assessment in primary immune thrombocytopenia: A prospective cohort study

Primary immune thrombocytopenia (ITP) is an autoimmune bleeding disorder, and chemokines have been shown to be dysregulated in autoimmune disorders. We conducted a prospective analysis to identify potential chemokines that could enhance the diagnostic accuracy and bleeding evaluation in ITP patients. In the discovery cohort, a Luminex-based assay was employed to quantify concentrations of plasma multiple chemokines. These levels were subjected to comparative analysis using a cohort of 60 ITP patients and 17 patients with thrombocytopenia other than ITP (non-ITP). Additionally, comparative evaluation was conducted between a subgroup of 12 ITP patients characterised by bleeding episodes (ITP-B, as defined by an ITP-2016 bleeding grade ≥2) and 33 ITP patients without bleeding episodes (ITP-NB, as defined by an ITP-2016 bleeding grade ≤1). Machine learning algorithms further identified CCL20, interleukin-2, CCL26, CCL25, and CXCL1 as promising indicators for accurate diagnosis of ITP and CCL21, CXCL8, CXCL10, CCL8, CCL3, and CCL15 as biomarkers for assessing bleeding risk in ITP patients. The results were confirmed using enzyme-linked immunosorbent assays in a validation cohort (43 ITP patients and 19 non-ITP patients). Overall, the findings suggest that specific chemokines show promise as potential biomarkers for diagnosis and bleeding evaluation in ITP patients.

In vitro modulation of T cells in myasthenia gravis by low-dose IL-2

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.

Analysis of Inflammatory and Regulatory Cytokines in the Milk of Dairy Cows with Mastitis: A Comparative Study with Healthy Animals

Bovine mastitis remains a major problem in the global dairy cattle industry. The acute invasion of udder by pathogens induces innate immune response as the first defence mechanism in subclinical and clinical mastitis. The aim of the study was to determine inflammatory and regulatory cytokines IL-2, IL-4, TGF-β1, IL-17A, beta-defensin 3 and IL-10 and their potential changes in milk of dairy cows with subclinical and clinical mastitis, and to compare the findings with healthy animals. Milk samples from 15 holstein Friesian breed cows were used in the study. Cows were divided into three groups based on their health status (5 healthy, 5 subclinical and 5 clinical animals). All samples were tested using immunohistochemistry to evaluate IL-2, IL-4, IL-10, IL17A, TGF-β1 and β-Def 3 proteins. Expression of all proteins was detected in all milk samples. High expression of IL-2, IL-4, IL17A, TGF-β1 was detected in healthy cows' milk and in milk of cows with subclinical and clinical mastitis. However, expression of IL-10 and β-Def 3 in milk samples of healthy cows was significantly higher compared to the milk of cows with subclinical and clinical mastitis (p < .001). IL-10 and β-Def 3 can be considered as informative biomarkers in diagnosis of subclinical and clinical mastitis.

Targeting CD25+ lymphoma cells with the antibody-drug conjugate camidanlumab tesirine as a single agent or in combination with targeted agents

Camidanlumab tesirine (ADCT-301) is a CD25-specific antibody-drug conjugate (ADC) employing SG3199, a highly cytotoxic DNA minor groove cross-linking pyrrolobenzodiazepine dimer. The ADC has shown early clinical antitumour activity in various cancers, including B- and T-cell lymphomas. We assessed its preclinical activity as a single agent in 57 lymphoma cell lines and in combination with selected drugs in T-cell lymphoma-derived cell lines. Cells were exposed to increasing concentrations of the ADC or SG3199 for 96 h, followed by an MTT proliferation assay. CD25 expression was measured at cell surface and RNA levels. Experiments with PDX-derived cell lines were used for validation studies. Camidanlumab tesirine presented more potent single agent in vitro cytotoxic activity in T- than B-cell lymphomas. In vitro activity was correlated with CD25 cell surface and RNA expression. In vitro activity was correlated with CD25 cell surface and RNA expression. When camidanlumab tesirine-containing combinations were evaluated in four T-cell lymphoma models, the most active partners were everolimus, copanlisib, venetoclax, vorinostat, and pralatrexate, followed by bortezomib, romidepsin, bendamustine, and 5-azacytidine. The strong camidanlumab tesirine single-agent anti-lymphoma activity and the in vitro synergisms with targeted agents identify potential combination partners for future clinical studies.

The role of interleukin-2 in graft-versus-host disease pathogenesis, prevention and therapy

Graft-versus-host disease (GVHD) is a significant complication following allogeneic hematopoietic cell transplantation (allo-HCT), posing substantial risks to patient survival. In the late follow-up phase of transplanted patients, GVHD is also a major cause of morbidity and disability, mostly due to low response to first-line steroids and the lack of effective standard therapies in the second line. This review provides a description of GVHD pathogenesis, with a focus on the central role of Interleukin-2 (IL-2). IL-2 is one of the critical mediators in the complex pathogenesis of GVHD, contributing to the intricate balance between regulatory T cells (Tregs) and effector T cells (Teffs). Due to this pivotal role, several studies investigate the potential of IL-2 as a therapeutic option for GVHD management. We discuss the outcomes of low-dose IL-2 therapies and their impact on Treg proliferation and steroid dependency reduction. Additionally, the effects of combining IL-2 with other treatments, such as extracorporeal photopheresis (ECP) and Treg-enriched lymphocyte infusions, are highlighted. Novel approaches, including modified IL-2 complexes and IL-2 receptor blockade, are explored for their potential in selectively enhancing Treg function and limiting Teff activation. The evolving understanding of IL-2's pivotal role in immune regulation presents promising prospects for applying treatment and prevention strategies for GVHD.

Evaluating Interleukin-2 and Its Receptors As Indicators of Acute Renal Graft Rejection

Introduction Interleukin-2 (IL-2) is a cytokine that exerts its actions via binding to a variety of interleukin-2 receptors (IL-2R), thereby stimulating T-cell response. Acute renal graft rejection (AR) is known to be mediated by CD8+ T-cells, through the IL-2 pathway. The aim of this study was to determine whether IL-2 and IL-2R could work as prognostic biomarkers of AR. Methods IL-2, IL-2R and Cystatin-C levels were measured in the serum of 50 patients who underwent a kidney transplant, once pre-operatively and at four different time points post-operatively (second, sixth, 14th day and third month). Of the total number of patients, ultimately 10 (20%) had an episode of AR. Results No statistically significant difference in IL-2 levels was found between those who experienced AR and those who did not, at any of the studied time points. On the other hand, measurement of IL-2R levels on the sixth and 14th day post-operatively showed that people with AR had a statistically significant increase in its value compared to patients who did not have an AR episode (p=0.027 and p=0.019, respectively). In addition, comparing the values ​​of IL-2R with that of Cystatin-C in different time periods, it was found that there is a significant positive linear correlation on the second and sixth postoperative day between the values ​​of the associated parameters (r=0.280, p=0.049 and r=0.372, p=0.008 respectively). Conclusion The measurement of IL-2R from the sixth to 14th postoperative day could be used as a reliable prognostic biomarker of AR, however additional studies and standardised diagnostic thresholds are required before the routine clinical application is feasible.

Development of novel humanized CD19/BAFFR bicistronic chimeric antigen receptor T cells with potent antitumor activity against B-cell lineage neoplasms

Chimeric antigen receptor T cell (CAR-T) therapy has shown remarkable efficacy in treating advanced B-cell malignancies by targeting CD19, but antigen-negative relapses and immune responses triggered by murine-derived antibodies remain significant challenges, necessitating the development of novel humanized multitarget CAR-T therapies. Here, we engineered a second-generation 4-1BB-CD3ζ-based CAR construct incorporating humanized CD19 single-chain variable fragments (scFvs) and BAFFR single-variable domains on heavy chains (VHHs), also known as nanobodies. The resultant CAR-T cells, with different constructs, were functionally compared both in vitro and in vivo. We found that the optimal tandem and bicistronic (BI) structures retained respective antigen-binding abilities, and both demonstrated specific activation when stimulated with target cells. At the same time, BI CAR-T cells (BI CARs) exhibited stronger tumour-killing ability and better secretion of interleukin-2 and tumour necrosis factor-alpha than single-target CAR-T cells. Additionally, BI CARs showed less exhaustion phenotype upon repeated antigen stimulation and demonstrated more potent and persistent antitumor effects in mouse xenograft models. Overall, we developed a novel humanized CD19/BAFFR bicistronic CAR (BI CAR) based on a combination of scFv and VHH, which showed potent and sustained antitumor ability both in vitro and in vivo, including against tumours with CD19 or BAFFR deficiencies.

CD122 is an activation marker ensuring proper proliferation of T cells in teleost

As one of subunits for interleukin-2 receptor (IL-2R), CD122 can bind to IL-2 and then activate downstream signal transduction to participate in adaptive immune response. Although CD122 has been identified and investigated from several teleost species, studies on its function at T-cell level are still scarce for lack of specific antibodies. In this study, a typical CD122 in Nile tilapia (Oreochromis niloticus) was characterized by bioinformatics analysis, cloned to produce retrovirus infected NIH/3T3 cells for mouse immunization. After cell fusion and screening, we successfully developed a mouse anti-tilapia CD122 monoclonal antibody (mAb), which could specifically recognize CD122 and identify CD122-producing T cells of tilapia. Using the mAb to detect, CD122 was found to widely distribute in immune-related tissues, and significantly elevate post Edwardsiella piscicida infection or T-cell activation. More importantly, the expansion of CD122+ T cells and up-regulation of CD122 occurred both in total T cells and T-cell subsets during T-cell activation upon in vitro stimulation or in vivo infection. These results indicate that CD122 can be used as a T-cell activation marker in tilapia. Notably, CD122 mAb blocking blunted the activation of MAPK/Erk and mTORC1 pathways, and inhibited T-cell proliferation, suggesting a critical role of CD122 in ensuring proper proliferation of tilapia T cells. Therefore, this study enriches the knowledge of T-cell responses in fish and provides new evidence for understanding the evolution of lymphocyte-mediated adaptive immunity.

Effects of adding antibiotics to an inactivated oil-adjuvant avian influenza vaccine on vaccine characteristics and chick health

During poultry immunization, antibiotics are typically added to inactivated oil-adjuvant avian influenza (AI) vaccines. Here, we evaluated the effects of adding ceftiofur, a third-generation cephalosporin, to an AI vaccine on vaccine stability and structure and on chick growth, immune efficacy, blood concentrations, biochemical and immunological indices, and gut microbiota. The results demonstrated that neither aqueous ceftiofur sodium nor ceftiofur hydrochloride oil emulsion formed a stable mixture with the vaccine. Adding ceftiofur formulations, particularly ceftiofur hydrochloride, at >4% significantly destabilized the vaccine's water-in-oil structures. Adding ceftiofur also increased vaccine malabsorption at the injection site; specifically, adding ceftiofur hydrochloride reduced H5N8 and H7N9 antibody titers after the first immunization (P < 0.05) and H7N9 antibody titers after the second immunization (P < 0.01). Serum drug concentrations did not differ significantly between the groups with ceftiofur sodium and hydrochloride addition. Ceftiofur addition increased postvaccination chick weight loss; compared with the vaccine alone, ceftiofur sodium-vaccine mixture increased chick weight significantly (P < 0.05). Ceftiofur addition also increased stress indices and reduced antioxidant capacity significantly (P < 0.05 or P < 0.01). Vaccination-related immune stress reduced gut microbiota diversity in chicks; ceftiofur addition reversed this change. AI vaccine immunization significantly reduced the relative abundance of Lactobacillus and Muribaculaceae but significantly increased that of Bacteroides and Eubacterium coprostanoligenes group. Ceftiofur addition restored the gut microbiota structure; in particular, ceftiofur hydrochloride addition significantly increased the abundance of the harmful gut microbes Escherichia-Shigella and Enterococcus, whereas ceftiofur sodium addition significantly reduced it. The changes in gut microbiota led to alterations in metabolic pathways related to membrane transport, amino acids, and carbohydrates. In conclusion, adding ceftiofur to the AI vaccine had positive effects on chick growth and gut microbiota modulation; however, different antibiotic concentrations and formulations may disrupt vaccine structure, possibly affecting vaccine safety and immunization efficacy. Thus, the addition of antibiotics to oil-adjuvant vaccines is associated with a risk of immunization failure and should be applied to poultry with caution.

Engineered cytokine/antibody fusion proteins improve IL-2 delivery to pro-inflammatory cells and promote antitumor activity

Progress in cytokine engineering is driving therapeutic translation by overcoming these proteins' limitations as drugs. The IL-2 cytokine is a promising immune stimulant for cancer treatment but is limited by its concurrent activation of both pro-inflammatory immune effector cells and antiinflammatory regulatory T cells, toxicity at high doses, and short serum half-life. One approach to improve the selectivity, safety, and longevity of IL-2 is complexing with anti-IL-2 antibodies that bias the cytokine toward immune effector cell activation. Although this strategy shows potential in preclinical models, clinical translation of a cytokine/antibody complex is complicated by challenges in formulating a multiprotein drug and concerns regarding complex stability. Here, we introduced a versatile approach to designing intramolecularly assembled single-agent fusion proteins (immunocytokines, ICs) comprising IL-2 and a biasing anti-IL-2 antibody that directs the cytokine toward immune effector cells. We optimized IC construction and engineered the cytokine/antibody affinity to improve immune bias. We demonstrated that our IC preferentially activates and expands immune effector cells, leading to superior antitumor activity compared with natural IL-2, both alone and combined with immune checkpoint inhibitors. Moreover, therapeutic efficacy was observed without inducing toxicity. This work presents a roadmap for the design and translation of cytokine/antibody fusion proteins.

Regulatory T cells: masterminds of immune equilibrium and future therapeutic innovations

Regulatory T cells (Tregs), a subset of CD4+T cells marked by the expression of the transcription factor forkhead box protein 3 (Foxp3), are pivotal in maintaining immune equilibrium and preventing autoimmunity. In our review, we addressed the functional distinctions between Foxp3+Tregs and other T cells, highlighting their roles in autoimmune diseases and cancer. We uncovered the dual nature of Tregs: they prevented autoimmune diseases by maintaining self-tolerance while contributing to tumor evasion by suppressing anti-tumor immunity. This study underscored the potential for targeted therapeutic strategies, such as enhancing Treg activity to restore balance in autoimmune diseases or depleting Foxp3+Tregs to augment anti-tumor immune responses in cancer. These insights laid the groundwork for future research and clinical applications, emphasizing the critical role of Foxp3+Tregs in immune regulation and the advancement of next-generation immunotherapies.

Coinhibitory Molecule VISTA Play an Important Negative Regulatory Role in the Immunopathology of Bronchial Asthma

Objective

To investigate the significance of VISTA in bronchial asthma and its impact on the disease.

Methods

Human peripheral blood of asthma children was gathered. The expression concentrations of VISTA, IL-4, IL-6, CD25, CD40L, and PD-L2 in peripheral blood plasma were detected by ELISA. We established the mouse model of asthma and intervened with agonistic anti-VISTA mAb (4C11) and VISTA fusion protein. ELISA, flow cytometry, and Western blotting were performed to detect the expression levels of Th1, Th2, and Th17 cell subsets and related characteristic cytokines, as well as the protein levels of MAPKs, NF-κB, and TRAF6 in lung tissues. In addition, the infiltration of eosinophils and inflammatory cells, airway mucus secretion, and VISTA protein expression in lung histopathological sections of different groups of mice were analyzed.

Results

The concentration of VISTA in human asthma group decreased significantly (p < 0.05); A positive correlation was observed between VISTA and CD40L. The intervention of 4C11 mAb and fusion protein respectively during the induction period increase the differentiation of Th1 cells and the secretion of IFN-γ, and inhibit the differentiation of Th2 and Th17 cells, as well as the secretion of IL-4, IL-5, IL-13 and IL-17, partially reduce the pathological changes of asthma in mouse lungs and correct the progress of asthma. The MAPK, NF-κB, and TRAF6 protein levels were the middle range in the 4C11 mAb and fusion protein groups (p < 0.05).

Conclusion

The findings suggest VISTA may play a negative regulatory role in the occurrence and development of bronchial asthma.

T cell exhaustion in human cancers

T cell exhaustion refers to a progressive state in which T cells become functionally impaired due to sustained antigenic stimulation, which is characterized by increased expression of immune inhibitory receptors, but weakened effector functions, reduced self-renewal capacity, altered epigenetics, transcriptional programme and metabolism. T cell exhaustion is one of the major causes leading to immune escape of cancer, creating an environment that supports tumor development and metastatic spread. In addition, T cell exhaustion plays a pivotal role to the efficacy of current immunotherapies for cancer. This review aims to provide a comprehensive view of roles of T cell exhaustion in cancer development and progression. We summerized the regulatory mechanisms that involved in T cell exhaustion, including transcription factors, epigenetic and metabolic reprogramming events, and various microenvironmental factors such as cytokines, microorganisms, and tumor autocrine substances. The paper also discussed the challenges posed by T cell exhaustion to cancer immunotherapies, including immune checkpoint blockade (ICB) therapies and chimeric antigen receptor T cell (CAR-T) therapy, highlightsing the obstacles encountered in ICB therapies and CAR-T therapies due to T cell exhaustion. Finally, the article provides an overview of current therapeutic options aimed to reversing or alleviating T cell exhaustion in ICB and CAR-T therapies. These therapeutic approaches seek to overcome T cell exhaustion and enhance the effectiveness of immunotherapies in treating tumors.

Harnessing IL-2 for immunotherapy against cancer and chronic infection: a historical perspective and emerging trends

IL-2 therapy, which enhances the function of CD8 + T cells, was initially employed as the cornerstone of immunotherapy against cancer. However, the impact of this therapy extends beyond CD8 + T cells to cells expressing IL-2R, such as endothelial cells and regulatory T cells (Tregs), resulting in various side effects. Consequently, IL-2 therapy has taken a step back from the forefront of treatment. Immune checkpoint inhibitors (ICIs), such as anti-PD-1/PD-L1 antibodies and CTLA-4 antibodies, are used because of their durable therapeutic responses and the reduced incidence of side effects. Nevertheless, only a small fraction of cancer patients respond to ICIs, and research on IL-2 as a combination treatment to improve the efficacy of these ICIs is ongoing. To mitigate side effects, efforts have focused on developing IL-2 variants that do not strongly bind to cells expressing IL-2Rα and favor signaling through IL-2Rβγ. However, recent studies have suggested that, in the context of persistent antigen stimulation models, effective stimulation of antigen-specific exhausted CD8 + T cells in combination with PD-1 inhibitors requires either 1) binding to IL-2Rα or 2) delivery via a fusion with PD-1. This review explores the historical context of IL-2 as an immunotherapeutic agent and discusses future directions for its use in cancer immunotherapy.

MicroRNA classification and discovery for major depressive disorder diagnosis: Towards a robust and interpretable machine learning approach

BACKGROUND

Major depressive disorder (MDD) is notably underdiagnosed and undertreated due to its complex nature and subjective diagnostic methods. Biomarker identification would help provide a clearer understanding of MDD aetiology. Although machine learning (ML) has been implemented in previous studies to study the alteration of microRNA (miRNA) levels in MDD cases, clinical translation has not been feasible due to the lack of interpretability (i.e. too many miRNAs for consideration) and stability.

METHODS

This study applied logistic regression (LR) model to the blood miRNA expression profile to differentiate patients with MDD (n = 60) from healthy controls (HCs, n = 60). Embedded (L1-regularised logistic regression) feature selector was utilised to extract clinically relevant miRNAs, and optimized for clinical application.

RESULTS

Patients with MDD could be differentiated from HCs with the area under the receiver operating characteristic curve (AUC) of 0.81 on testing data when all available miRNAs were considered (which served as a benchmark). Our LR model selected miRNAs up to 5 (known as LR-5 model) emerged as the best model because it achieved a moderate classification ability (AUC = 0.75), relatively high interpretability (feature number = 5) and stability (ϕ̂Z=0.55) compared to the benchmark. The top-ranking miRNAs identified by our model have demonstrated associations with MDD pathways involving cytokine signalling in the immune system, the reelin signalling pathway, programmed cell death and cellular responses to stress.

CONCLUSION

The LR-5 model, which is optimised based on ML design factors, may lead to a robust and clinically usable MDD diagnostic tool.

Tyrosine phosphorylation of both STAT5A and STAT5B is necessary for maximal IL-2 signaling and T cell proliferation

Cytokine-mediated STAT5 protein activation is vital for lymphocyte development and function. In vitro tyrosine phosphorylation of a C-terminal tyrosine is critical for activation of STAT5A and STAT5B; however, the importance of STAT5 tyrosine phosphorylation in vivo has not been assessed. Here we generate Stat5a and Stat5b tyrosine-to-phenylalanine mutant knockin mice and find they have greatly reduced CD8+ T-cell numbers and profoundly diminished IL-2-induced proliferation of these cells, and this correlates with reduced induction of Myc, pRB, a range of cyclins and CDKs, and a partial G1→S phase-transition block. These mutant CD8+ T cells also exhibit decreased IL-2-mediated activation of pERK and pAKT, which we attribute in part to diminished expression of IL-2Rβ and IL-2Rγ. Our findings thus demonstrate that tyrosine phosphorylation of both STAT5A and STAT5B is essential for maximal IL-2 signaling. Moreover, our transcriptomic and proteomic analyses elucidate the molecular basis of the IL-2-induced proliferation of CD8+ T cells.

IFNγ Production by Functionally Reprogrammed Tregs Promotes Antitumor Efficacy of OX40/CD137 Bispecific Agonist Therapy

Regulatory T cells (Treg) are highly enriched within many tumors and suppress immune responses to cancer. There is intense interest in reprogramming Tregs to contribute to antitumor immunity. OX40 and CD137 are expressed highly on Tregs, activated and memory T cells, and NK cells. In this study, using a novel bispecific antibody targeting mouse OX40 and CD137 (FS120m), we show that OX40/CD137 bispecific agonism induces potent antitumor immunity partially dependent upon IFNγ production by functionally reprogrammed Tregs. Treatment of tumor-bearing animals with OX40/CD137 bispecific agonists reprograms Tregs into both fragile Foxp3+ IFNγ+ Tregs with decreased suppressive function and lineage-instable Foxp3- IFNγ+ ex-Tregs. Treg fragility is partially driven by IFNγ signaling, whereas Treg instability is associated with reduced IL2 responsiveness upon treatment with OX40/CD137 bispecific agonists. Importantly, conditional deletion of Ifng in Foxp3+ Tregs and their progeny partially reverses the antitumor efficacy of OX40/CD137 bispecific agonist therapy, revealing that reprogramming of Tregs into IFNγ-producing cells contributes to the anti-tumor efficacy of OX40/CD137 bispecific agonists. These findings provide insights into mechanisms by which bispecific agonist therapies targeting costimulatory receptors highly expressed by Tregs potentiate antitumor immunity in mouse models.

SIGNIFICANCE

The bispecific antibody FS120, an immunotherapy currently being tested in the clinic, partially functions by inducing anti-tumor activity of Tregs, which results in tumor rejection.

Immunomodulatory properties of chicken cathelicidin-2 investigated on an ileal explant culture

As the threat posed by antimicrobial resistance grows more crucial, the development of compounds that can replace antibiotics becomes increasingly vital. Chicken cathelicidin-2 (Cath-2) belongs to the group of Host Defense Peptides (HDPs), which could provide a feasible solution for the treatment of gastrointestinal infections in poultry. It is a small peptide produced by the heterophil granulocytes of chickens as part of the innate immune response, and its immunomodulatory activity has already been demonstrated in several cell types. In this study, the effects of Cath-2 on the intestinal immune response were examined using ileal explant cultures isolated from chicken. Regarding our results, Cath-2 displayed a potent anti-inflammatory effect as it alleviated the LTA-caused elevation of interleukin (IL)-6 and IL-2 concentrations, and that of the IFN-γ/IL-10 ratio, furthermore, it increased the concentration of IL-10, alleviating the LTA-evoked decreased level of the anti-inflammatory cytokine. Moreover, when applied alone, it elevated the concentrations of IL-6, CXCLi2, and IL-2, providing evidence of its complex immunomodulatory mechanisms. In summary, Cath-2 was able to modulate the immune response of the intestinal wall not only by reducing pro-inflammatory cytokine release, but also through immune stimulation, demonstrating that it has the ability to improve innate immunity via a complex mechanism that may make it a suitable candidate for the control of intestinal infections.

The differences in cytokine signatures between severe fever with thrombocytopenia syndrome (SFTS) and hemorrhagic fever with renal syndrome (HFRS)

Severe fever with thrombocytopenia syndrome (SFTS) virus and hantavirus are categorized under the Bunyavirales order. The severe disease progression in both SFTS and hemorrhagic fever with renal syndrome (HFRS) is associated with cytokine storms. This study aimed to explore the differences in cytokine profiles and immune responses between the two diseases. A cross-sectional, single-center study involved 100 participants, comprising 46 SFTS patients, 48 HFRS patients, and 6 healthy controls. The study employed the Luminex cytokine detection platform to measure 48 cytokines. The differences in cytokine profiles and immune characteristics between the two diseases were further analyzed using multiple linear regression, principal component analysis, and random forest method. Among the 48 cytokines tested, 30 showed elevated levels in SFTS and/or HFRS compared to the healthy control group. Furthermore, there were 19 cytokines that exhibited significant differences between SFTS and HFRS. Random forest analysis suggested that TRAIL and CTACK were predictive of SFTS, while IL2Ralpha, MIG, IL-8, IFNalpha2, HGF, SCF, MCP-3, and PDGFBB were more common with HFRS. It was further verified by the receiver operating characteristic with area under the curve >0.8 and P-values <0.05, except for TRAIL. Significant differences were observed in the cytokine profiles of SFTS and HFRS, with TRAIL, IL2Ralpha, MIG, and IL-8 being the top 4 cytokines that most clearly distinguished the two diseases.

IMPORTANCE

SFTS and HFRS differ in terms of cytokine immune characteristics. TRAIL, IL-2Ralpha, MIG, and IL-8 were the top 4 that differed markedly between SFTS and HFRS.

Cantharidin overcomes IL-2Rα signaling-mediated vorinostat resistance in cutaneous T-cell lymphoma through reactive oxygen species

BACKGROUND

Vorinostat (SAHA) is a histone deacetylase inhibitor that has shown clinical efficacy against advanced cutaneous T-cell lymphoma (CTCL). However, only a subset of patients with CTCL (30-35%) respond to SAHA and the response is not always sustainable. Thus, understanding the mechanisms underlying evasive resistance in this cancer is an unmet medical need to improve the efficacy of current therapies.

PURPOSE

This study aims to identify factors contributing to resistance against SAHA in CTCL and ways to mitigate it.

METHODS AND RESULTS

In this study, we demonstrated that attenuated reactive oxygen species (ROS) induces the expression of interleukin (IL)-2Rα, one of the IL-2 receptors, which drives resistance to SAHA in CTCL. We also determined that cantharidin could overcome SAHA resistance to CTCL by blocking IL-2Rα-related signaling via ROS-dependent manner. Mechanistically, accelerated translation of IL-2Rα contributes to excessive IL-2Rα protein formation as a result of reduced ROS levels in SAHA-resistant CTCL. At the same time, amplified IL-2R signals are evidenced by strengthened interaction of IL-2Rβ with IL-2Rγ and Janus kinase/signal transducer and activator of transcription molecules, and by increased expression of protein kinase B (AKT)/mTOR and mitogen-activated protein kinase signaling. Moreover, cantharidin, an active constituent of Mylabris used in traditional Chinese medicine, markedly increased ROS levels, and thereby restrained IL-2Rα translation, resulting in suppression of downstream pathways in SAHA-resistant cells. Cantharidin is also found to synergize with SAHA and triggers SAHA-resistant cell death via IL-2R signaling both in vitro and in vivo.

CONCLUSION

Our study uncovers a novel molecular mechanism of acquired SAHA resistance and also suggests that using cantharidin is a potential approach to overcome CTCL therapy resistance. Our findings underlie the therapeutic potential of cantharidin in treating CTCL.

The Novel Fusion Protein Melittin-MIL-2 Exhibits Strong Antitumor Immune Effect in Lung Adenocarcinoma Cell A549

In previous studies, we developed a novel fusion protein named "melittin-MIL-2" which exhibited more anti-tumor activity. However, it remains unclear whether melittin-MIL-2 possesses antitumor immune effect on lung adenocarcinoma. In this study, the immune effect and mechanism of melittin-MIL-2 inhibiting the growth and invasion of lung adenocarcinoma will be investigated, in order to provide novel perspectives for the immunotherapy of lung cancer. The results indicated that melittin-MIL-2 promoted T cell proliferation, enhanced NK cell cytotoxicity, and boosted IFN-γ secretion in PBMCs. After melittin-MIL-2 stimulation, perforin expression and LAK/NK-like killing activities of human PBMCs and NK cells were significantly enhanced. Melittin-MIL-2 is capable of hampering the development and proliferation of lung adenocarcinoma cell A549. ICAM-1 and Fas expression in A549 cells exposed to melittin-MIL-2 rose significantly. The expression levels of TLR8 and VEGF in A549 cells decreased significantly after melittin-MIL-2 stimulation. In vivo, melittin-MIL-2 substantially impeded the growth of lung adenocarcinoma and formed an immune-stimulating microenvironment locally in tumor tissues. In conclusion, the novel fusion protein melittin-MIL-2 exhibits strong anti-tumor immune effect in lung adenocarcinoma cell A549 via activating the LFA-1/ICAM-1 and Fas/FasL pathways to enhance cytolytic activity, upregulating the secretion of IFN-γ and perforin, and boosting LAK/NK-like killing activities. Immuno-effector cells and their secreted cytokines can form immune stimulation microenvironment locally in lung adenocarcinoma Lewis mice tissue.

Effect of IL-2 polymorphism rs2069762 on single-unit cord blood transplant outcomes

BACKGROUND

Interleukin-2 (IL-2) is one of the most important cytokines that regulate the activation and proliferation of T cells and natural killer cells. The production of IL-2 may be affected by polymorphisms in the promoter region of the IL-2 gene (rs2069762). In allogeneic hematopoietic cell transplantation (HCT) from adult donors, rs2069762 has been associated with the incidence of acute and chronic graft-versus-host disease (GVHD). However, the impacts of IL-2 polymorphism on cord blood transplantation (CBT) outcomes remain unclear.

OBJECTIVE

The objective of this study was to assess the impact of IL-2 polymorphism rs2069762 on transplant outcomes, such as hematopoietic recovery, GVHD, overall survival, relapse, and non-relapse mortality (NRM) after CBT.

STUDY DESIGN

We conducted a retrospective analysis of data from adult patients who underwent single-unit CBT at our institution from November 2005 to March 2023 for whom DNA samples from recipients and donors were available. IL-2 genotyping was performed using real-time polymerase chain reaction with the TaqMan® SNP genotyping assay for rs2069762.

RESULTS

A total of 143 recipient and donor pairs were included in this study. The proportion of recipient IL-2 polymorphism rs2069762 was 48 % (n = 69) for AA, 42 % (n = 60) for CA, and 10 % (n = 14) for CC. The proportion of donor IL-2 polymorphism rs2069762 was 43 % (n = 61) for AA, 48 % (n = 69) for CA, and 9 % (n = 13) for CC. In the multivariate analysis, the use of an rs2069762 CA + CC donor was associated with lower neutrophil recovery compared to an rs2069762 AA donor (hazard ratio [HR], 0.66; 95 % confidence interval [CI], 0.50-0.88; P = 0.004). Furthermore, recipients of rs2069762 CA + CC were associated with higher NRM compared to recipients of rs2069762 AA (HR, 2.32; 95 % CI, 1.01-5.34; P = 0.047). Serum IL-2 levels at 8 weeks were significantly higher in rs2069762 CA + CC recipients compared to those with rs2069762 AA recipients (P = 0.014).

CONCLUSION

Our data showed that donor IL-2 polymorphism affects neutrophil recovery and recipient IL-2 polymorphism affects NRM in adults undergoing single-unit CBT. The polymorphism of IL-2 rs2069762 in recipients and donors might be associated with the clinical outcomes of single-unit CBT.

Interleukin-2 mediated associations between gut microbiota and acute myeloid leukemia: A population-based mediation Mendelian randomization study

The relationship between the gut microbiota and acute myeloid leukemia (AML) has been established, but the exact role of interleukin (IL) in mediating this relationship has remained unclear. This study aimed to utilize whether interleukins mediate the relationships between gut microbiota and AML, thereby identifying potential novel targets for future AML treatment. Mendelian randomization (MR) is a method for finding the causality of exposure and outcome. Final instrumental variables were selected based on MR assumptions, and used to judge validity of the results. Our study identified risk and protective factors for AML, and interleukin-related gut microbiota. Finally, mediation MR analyses resulted in Interleukin-2 (IL-2) mediated associations between Clostridiaceae 1, Clostridium sensu stricto 1 and AML, with IL-2 respectively explaining 13.96 % and 12.11 % of the total effect of the aforementioned gut microbiota on AML. Our results successfully identified causal effects between specific gut microbiota, AML, and interleukins, while also elucidating the mediating role of IL-2 in these associations using MR analysis. These findings provide valuable insights into potential therapeutic targets for AML treatment.

Regulatory T Cell Dysfunction in Autoimmune Diseases

Regulatory T cells (Tregs), a suppressive subpopulation of T cells, are potent mediators of peripheral tolerance, responsible for immune homeostasis. Many autoimmune diseases exhibit disruptions in Treg function or quantity, resulting in an imbalance between protective and pathogenic immune cells. Selective expansion or manipulation of Tregs is a promising therapeutic approach for autoimmune diseases. However, the extensive diversity of Treg subpopulations and the multiple approaches used for Treg identification leads to high complexity, making it difficult to develop a successful treatment capable of modulating Tregs. In this review, we describe the suppressive mechanisms, subpopulations, classification, and identification methodology for Tregs, and their role in the pathogenesis of autoimmune diseases.

Chemokines and Cytokines in Immunotherapy of Melanoma and Other Tumors: From Biomarkers to Therapeutic Targets

Chemokines and cytokines represent an emerging field of immunotherapy research. They are responsible for the crosstalk and chemoattraction of immune cells and tumor cells. For instance, CXCL9/10/11 chemoattract effector CD8+ T cells to the tumor microenvironment, making an argument for their promising role as biomarkers for a favorable outcome. The cytokine Interleukin-15 (IL-15) can promote the chemokine expression of CXCR3 ligands but also XCL1, contributing to an important DC-T cell interaction. Recruited cytotoxic T cells can be clonally expanded by IL-2. Delivering or inducing these chemokines and cytokines can result in tumor shrinkage and might synergize with immune checkpoint inhibition. In addition, blocking specific chemokine and cytokine receptors such as CCR2, CCR4 or Il-6R can reduce the recruitment of tumor-associated macrophages (TAMs), myeloid-derived suppressor cells (MDSCs) or regulatory T cells (Tregs). Efforts to target these chemokines and cytokines have the potential to personalize cancer immunotherapy further and address patients that are not yet responsive because of immune cell exclusion. Targeting cytokines such as IL-6 and IL-15 is currently being evaluated in clinical trials in combination with immune checkpoint-blocking antibodies for the treatment of metastatic melanoma. The improved overall survival of melanoma patients might outweigh potential risks such as autoimmunity. However, off-target toxicity needs to be elucidated.

Raffinose Ameliorates DSS-Induced Colitis in Mice by Modulating Gut Microbiota and Targeting the Inflammatory TLR4-MyD88-NF-κB Signaling Pathway

This study aimed to explore the protective effects of raffinose (Raf) against inflammatory bowel disease in mice with colitis. Mice were administered 100, 200, or 400 mg/kg Raf for 21 d, followed by drinking-water containing 3% dextran sulfate sodium salt (DSS) for 3 d. Thereafter, the phenotype, pathological lesions in the colon, cytokines levels, and gut microbiota were evaluated. Treatment with Raf reduced the severity of the pathological changes in the colon, mitigating the reduction in colon length. Following Raf intervention, serum levels of inflammatory cytokines (IL-2, IL-6, IL-1β, and TNF-α) tended to return to normal. These results suggest that the anti-inflammatory effects of Raf are associated with a reduction in TLR4-MyD88-NF-κB pathway expression in mouse colonic tissues. Analysis of gut microbiota abundance and its correlation with colitis parameters revealed that DSS-induced dysbiosis was partially mitigated by Raf. In conclusion, Raf exerts a protective effect in colitis by modulating the gut microbiota and TLR4-MyD88-NF-κB pathway.

MB2033, an anti-PD-L1 × IL-2 variant fusion protein, demonstrates robust anti-tumor efficacy with minimal peripheral toxicity

Interleukin-2 (IL-2), a cytokine with pleiotropic immune effects, was the first approved cancer immunotherapy agent. However, IL-2 is associated with systemic toxicity due to binding with its ligand IL-2Rα, such as vascular leakage syndrome, limiting its clinical applications. Despite efforts to extend the half-life of IL-2 and abolish IL-2Rα interactions, the risk of toxicity remains unresolved. In this study, we developed the bispecific fusion protein MB2033, comprising a novel IL-2 variant (IL-2v) connected to anti-programmed death ligand 1 (PD-L1) via a silenced Fc domain. The IL-2v of MB2033 exhibits attenuated affinity for IL-2Rβγ without binding to IL-2Rα. The binding affinity of MB2033 for PD-L1 is greater than that for IL-2Rβγ, indicating its preferential targeting of PD-L1+ tumor cells to induce tumor-specific immune activation. Accordingly, MB2033 exhibited significantly reduced regulatory T cell activation, while inducing comparable CD8+ T cell activation to recombinant human IL-2 (rhIL-2). MB2033 induced lower immune cell expansion and reduced cytokine levels compared with rhIL-2 in human peripheral blood mononuclear cells, indicating a decreased risk of peripheral toxicity. MB2033 exhibited superior anti-tumor efficacy, including tumor growth inhibition and complete responses, compared with avelumab monotherapy in an MC38 syngeneic mouse model. In normal mice, MB2033 was safer than non-α IL-2v and tolerable up to 30 mg/kg. These preclinical results provide evidence of the dual advantages of MB2033 with an enhanced safety and potent clinical efficacy for cancer treatment.