Soluble Lymphocyte Activation Gene-3 Research Articles

Soluble lymphocyte activation gene-3 (sLAG3) and CD4/CD8 ratio dynamics as predictive biomarkers in patients undergoing immune checkpoint blockade for solid malignancies

BackgroundThe search for biomarkers to identify suitable candidates for immune checkpoint inhibitor (ICI) therapy remains ongoing. We evaluate how soluble levels of the next generation immune checkpoint Lymphocyte Activation Gene-3 (sLAG-3) and its association with circulating T lymphocyte subsets could pose as a novel biomarker to predict outcome to ICI therapy.MethodsCirculating levels of sLAG3 were analyzed using multiplex immunoassay in n = 84 patients undergoing ICI therapy for advanced solid cancer, accompanied by flow cytometry analyses of peripheral blood mononuclear cells (PBMCs).ResultsUni- and multivariate analysis shows that patients with higher sLAG3 concentrations before ICI therapy had a significantly impaired progression-free (PFS) and overall survival (OS) (HRPFS: 1.005 [95%CI: 1.000–1.009], p = 0.039; HROS: 1.006 [95%CI: 1.001–1.011], p = 0.015). The CD4/CD8 cell ratio and its dynamics during therapy were strong predictors of PFS and OS with patients with a decreasing ratio between baseline and after 1–2 cycles having an improved median OS compared to patients with increasing values (p = 0.012, HR: 3.32). An immunological score combining sLAG3 and the CD4/CD8 ratio showed the highest predictive potential (HROS: 10.3).ConclusionPending prospective validation, sLAG3 and correlating circulating T-cell subsets can be used as a non-invasive predictive marker to predict outcome to ICI therapy to help identifying ideal ICI candidates in the future.

LAG-3 expression in microglia regulated by IFN-γ/STAT1 pathway and metalloproteases.

Microglia are resident innate immune cells in the central nervous system (CNS) and play important roles in the development of CNS homeostasis. Excessive activation and neurotoxicity of microglia are observed in several CNS disorders, but the mechanisms regulating their activation remain unclear. Immune checkpoint molecules are expressed on activated immune cells and regulate their activation in peripheral immunity. However, the expression mechanism of immune checkpoint molecules in activated microglia is still unknown. Here, we analyzed the expression of immune checkpoint molecules in activated microglia using the mouse microglial cell line BV2 and primary cultured microglia. The expression of lymphocyte activation gene-3 (LAG-3), a type of immune checkpoint molecule, was increased in microglia activated by IFN-γ. IFN-γ-induced LAG-3 expression in microglia was suppressed by transfection of siRNA targeting STAT1. LAG-3 has two forms, membrane and soluble, and both forms were upregulated in microglia activated by IFN-γ. The production of soluble LAG-3 was suppressed by treatment with inhibitors of metalloproteinases such as ADAM10 and ADAM17. IFN-γ administration into cisterna magna of mice increased LAG-3 expression in spinal microglia. Furthermore, LAG-3 knockdown in microglia promoted nitric oxide production by IFN-γ. Our results demonstrate that LAG-3 expression in microglia is induced by the IFN-γ-STAT1 pathway and soluble LAG-3 production is regulated via cleavage of membranous LAG-3 by metalloproteinases including ADAM10 and ADAM17.

A soluble LAG-3 protein (eftilagimod alpha) and an anti-PD-L1 antibody (avelumab) tested in a phase I trial: a new combination in immuno-oncology

Eftilagimod alpha (efti) is a major histocompatibility complex class II agonist activating antigen-presenting cells which leads to greater systemic type 1 T helper response and more cytotoxic CD8+ T-cell activation. This phase I trial evaluated the administration of efti, a soluble lymphocyte activation gene-3 (LAG-3) protein, combined with the anti-programmed death-ligand 1 (PD-L1) antibody avelumab in advanced solid tumors. Patients with heavily pretreated metastatic solid tumors received intravenous avelumab (800 mg) combined with subcutaneously administered efti (6 or 30 mg) for up to 12 cycles, followed by avelumab monotherapy. The primary endpoint was the assessment of the recommended phase II dose (RP2D) of efti in combination with avelumab. Twelve patients with different tumor entities were enrolled (six patients in each cohort). During treatment, no dose-limiting toxicities occurred, and the severity of most adverse events was grade 1 or 2. In total, nine serious adverse events were documented, resulting in a fatal outcome in two cases, but none of them were assessed to be treatment related. Five patients (42%) achieved partial response. The median progression-free survival was 1.96 months and the median overall survival was not reached, with a 12-month survival rate of 75%. Subcutaneously administered efti plus avelumab was well tolerated, and efti of 30 mg was determined to be RP2D. The activity is promising and warrants further investigation in future phase II trials.

Phase I, multicenter, open-label study of intravenous VCN-01 oncolytic adenovirus with or without nab-paclitaxel plus gemcitabine in patients with advanced solid tumors

BackgroundVCN-01 is an oncolytic adenovirus (Ad5 based) designed to replicate in cancer cells with dysfunctional RB1 pathway, express hyaluronidase to enhance virus intratumoral spread and facilitate chemotherapy and immune cells...

Serum Inflammation Markers in Tuberculosis

Abstract Tuberculosis remains one of the leading infectious cause of death in the world. The goals of screening are to detect active tuberculosis early enough and to identify individuals eligible for preventive therapy to reduce a po tential co-infection by tuberculosis. Plasma/serum screening for selected potential biomarkers could represent a suitable method of tuberculosis diagnosis and treatment outcome. Furthermore, monitoring of tuberculosis treatment is crucial to clinical decision-making and besides the plasmatic concentration of administered antituberculosis drugs, the biomarkers appear to play a significant role in the estimation of the real therapeutical impact. The current standard remains focused on culture conversion, especially two-month culture status, which has a relatively low sensitivity. Identification of non-sputum-based biomarkers of the treatment respond would be beneficial for individual monitoring of tuberculosis patients. This mini-review describes several serological/plasmatic markers that can be analyzed by simple immunoassays as ELISA method, e.g. C-reactive protein, soluble intercellular adhesion molecule-1, soluble urokinase plasminogen activator receptor, soluble lymphocyte activation gene-3, granzyme B and soluble tumor necrosis factor receptor one and two as reliable enough as an indicator of successful treatment of tuberculosis.

Eftilagimod alpha, a soluble lymphocyte activation gene-3 (LAG-3) protein plus pembrolizumab in patients with metastatic melanoma

BackgroundTo evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of eftilagimod alpha (efti), a soluble lymphocyte activation gene-3 protein, in combination with the programmed cell death-1 (PD-1) antagonist pembrolizumab.MethodsThe study was...

Decreased LAG3 expression on T effector cells and regulatory T cells in SAA.

To investigate the expression of lymphocyte activation gene 3(LAG3) on CD8+T effector cells (Teffs), CD4+ Teffs and regulatory T cells (Tregs) in patients with severe aplastic anemia (SAA). We detected the expression of LAG3 on CD8+ Teffs, CD4+ Teffs and Tregs in SAA patients and healthy controls (HC) by flow cytometry, and analyzed its correlation with the immune status and severity of the disease. ELISA was used to detect soluble LAG3(sLAG3). The expression of LAG3 on CD8+ Teffs, CD4+ Teffs and Tregs in untreated SAA patients were significantly lower than those in HC group (P < 0.05). After IST, the LAG3 expression of target cells increased to a level even higher than that in HC group (P < 0.05). LAG3 on T cell subsets was closely related toimmune status and severity of the disease. The concentration of sLAG3 in these groups showed similar trends. LAG3 was not a prognostic factor of response. The decreased expression of LAG3 on CD8+ Teffs, CD4+ Teffs and Tregs may be involved in the pathogenesis of SAA. LAG3 intervention may have therapeutic potential in treating SAA.

Lymphocyte-Activation Gene 3 (LAG3) Protein as a Possible Therapeutic Target for Parkinson's Disease: Molecular Mechanisms Connecting Neuroinflammation to α-Synuclein Spreading Pathology.

Parkinson’s disease (PD) is the most common neurodegenerative movement disorder without any objective biomarker available to date. Increasing evidence highlights the critical role of neuroinflammation, including T cell responses, and spreading of aggregated α-synuclein in PD progression. Lymphocyte-activation gene 3 (LAG3) belongs to the immunoglobulin (Ig) superfamily expressed by peripheral immune cells, microglia and neurons and plays a key role in T cell regulation. The role of LAG3 has been extensively investigated in several human cancers, whereas until recently, the role of LAG3 in the central nervous system (CNS) has been largely unknown. Accumulating evidence highlights the potential role of LAG3 in PD pathogenesis, mainly by binding to α-synuclein fibrils and affecting its endocytosis and intercellular transmission, which sheds more light on the connection between immune dysregulation and α-synuclein spreading pathology. Serum and cerebrospinal fluid (CSF) soluble LAG3 (sLAG3) levels have been demonstrated to be potentially associated with PD development and clinical phenotype, suggesting that sLAG3 could represent an emerging PD biomarker. Specific single nucleotide polymorphisms (SNPs) of the LAG3 gene have been also related to PD occurrence especially in the female population, enlightening the pathophysiological background of gender-related PD clinical differences. Given also the ongoing clinical trials investigating various LAG3-targeting strategies in human diseases, new opportunities are being developed for PD treatment research. In this review, we discuss recent preclinical and clinical evidence on the role of LAG3 in PD pathogenesis and biomarker potential, aiming to elucidate its underlying molecular mechanisms.

Association of LAG3 genetic variation with an increased risk of PD in Chinese female population

BackgroundEmerging evidence suggests that α-synuclein (α-syn) aggregation and intercellular transmission contributes to pathogenesis of Parkinson’s disease (PD) and the toxic fibrillary α-syn binds lymphocyte-activation gene 3 (LAG3) receptor that mediates α-syn transmission. The deletion of LAG3 in animal models was shown to limit α-syn spreading and alleviate the pathological changes of dopaminergic neurons and animal behavioral deficits induced by α-syn aggregation. However, little is known about the genetic association of LAG3 variation with human PD development.ObjectiveHere we investigated LAG3 single nucleotide polymorphisms (SNPs) and examined the levels of soluble LAG3 (sLAG3) of CSF and serum from Chinese PD patients.MethodsWe enrolled 646 PD patients and 536 healthy controls to conduct a case-control study. All the participants were genotyped using Sequenom iPLEX Assay and the partial cerebrospinal fluid (CSF) and serum samples were assessed by Meso Scale Discovery electrochemiluminescence (MSD-ECL) immunoassay to measure sLAG3 concentration.ResultsAs a result, distributions of rs1922452-AA (1.975, 95% confidence interval (CI) 1.311–2.888, p = 0.001) and rs951818-CC (OR = 2.03, 95% CI 1.369–3.010, p = 0.001) genotype frequencies were found higher in the female PD patients than controls, respectively, and a strong linkage disequilibrium (LD) was calculated on the variants. The level of sLAG3 in CSF of PD patients was found to significantly differ from that of controls (51.56 ± 15.05 pg/ml vs 88.49 ± 62.96 pg/ml, p < 0.0001). Meanwhile, the concentration of α-synuclein in CSF of patients was significantly lower than that of controls (939.9 ± 2900 pg/ml vs 2476 ± 4403 pg/ml, p < 0.0001) and the level of sLAG3 was detected to be positive correlation with that of α-synuclein in the control group (r = 0.597, p = 0.0042), but not in PD group (r = 0.111, p = 0.408).ConclusionIn summary, our data suggested that LAG3 SNPs increase the PD risk of Chinese female population and the sLAG3 may be a potential biomarker predicted for PD development.

LAG3: The Biological Processes That Motivate Targeting This Immune Checkpoint Molecule in Human Cancer.

The programmed cell death 1 (PD-1) pathway is an important regulator of immune responses in peripheral tissues, including abnormal situations such as the tumor microenvironment. This pathway is currently the principal target for immunotherapeutic compounds designed to block immune checkpoint pathways, with these drugs improving clinical outcomes in a number of solid and hematological tumors. Medical oncology is experiencing an immune revolution that has scientists and clinicians looking at alternative, non-redundant inhibitory pathways also involved in regulating immune responses in cancer. A variety of targets have emerged for combinatorial approaches in immune checkpoint blockade. The main purpose of this narrative review is to summarize the biological role of lymphocyte activation gene 3 (LAG3), an emerging targetable inhibitory immune checkpoint molecule. We briefly discuss its role in infection, autoimmune disease and cancer, with a more detailed analysis of current data on LAG3 expression in breast cancer. Current clinical trials testing soluble LAG3 immunoglobulin and LAG3 antagonists are also presented in this work.

Abstract 2399: LAG-3/PD-L1 mAb2 can overcome PD-L1-mediated compensatory upregulation of LAG-3 induced by single-agent checkpoint blockade

Abstract FS118, currently tested in Phase I clinical trial in patients with advanced malignancies (NCT03440437), is a first-in-class bispecific antagonistic antibody (known as mAb2) targeting LAG-3 (Lymphocyte-Activation Gene 3) and PD-L1 (Programmed Death-Ligand 1), two immune checkpoint molecules that promote tumour escape from immune surveillance. Resistance to anti-PD-1 treatment is associated with upregulation of other checkpoint inhibitor receptors such as LAG-3. Dual targeting in immune checkpoint blockade (ICB) using bispecific monoclonal antibodies could potentially overcome this resistance, further increase the clinical benefit of ICB therapy and prevent relapse or resistance after immunotherapy. In a syngeneic model we used a surrogate mAb2 of FS118 (blocking both mPD-L1 and mLAG-3 binding to their receptors) to determine the effect of dual checkpoint blockade on tumour growth and to elucidate the modulation of the underlying immune mechanisms following treatment with the mAb2. Dual blockade of LAG-3 and PD-L1 with the surrogate mAb2 in the MC38 tumour-bearing mice model resulted in an increased anti-tumour activity comparable to a combination of the single agents targeting LAG-3 and PD-L1. Moreover, the mAb2 and single agent combination resulted in distinct modulations of LAG-3 and PD-L1 cell surface expression within the spleen and tumour microenvironment (TME). While both the mAb2 and combination therapy significantly reduced the number of free PD-L1 binding sites on CD4+ and CD8+ T cells in spleen and TME, total LAG-3 cell surface expression increased following treatment with the combination, whereas it reduced with mAb2 treatment. In addition, analysis of serum samples collected at various timepoints confirmed evidence of drug target engagement with increasing levels of both soluble LAG-3 (sLAG-3) and soluble PD-L1 (sPD-L1) in the mAb2 treated animals. Modulation of sPD-L1 levels in the serum of treated animals was also observed in cynomolgus monkeys treated with FS118. These data provide a strong rationale for investigating both cell surface and soluble LAG-3 and PD-L1 levels as potential pharmacodynamic biomarkers in further clinical development. Citation Format: Mustapha Faroudi, Matthew Kraman, Natalie Fosh, Claire Reader, Daniel Gliddon, Claire Seal, Christa Lucas, Alexander Koers, Mateusz Wydro, Michelle Morrow, Neil Brewis. LAG-3/PD-L1 mAb2 can overcome PD-L1-mediated compensatory upregulation of LAG-3 induced by single-agent checkpoint blockade [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2399.

Soluble LAG3 acts as a potential prognostic marker of gastric cancer and its positive correlation with CD8+T cell frequency and secretion of IL-12 and INF-γ in peripheral blood.

Gastric cancer (GC) is the second most common lethal cancer worldwide and lymphocyte-activation gene 3 (LAG3) as a therapeutic target for cancers has been investigated. Herein, our study is to clarify the value of peripheral blood (PB) soluble LAG-3 (sLAG3) in GC. Peripheral serum samples of GC patients and healthy people were collected for the measurement of serum levels of sLAG3, carcinoembryonic antigen (CEA), IL-12 and IFN-γ. Additionally, ROC and Kaplan-Meier curves were adopted to identify the diagnostic and prognostic values of sLAG-3 in patients with GC. Then, GC-bearing mice were treated with recombinant sLAG3. The tumor volume was measured, and CD8+T cell frequency was detected in PB and tumor-ininfiltrating area. Additionally, the expression of IL-12 and IFN-γ in T cells was assayed and the overall survival of mice was analyzed. sLAG3 in PB was poorly expressed and its expression was positively correlated with IL-12 and IFN-γ expression in GC patients. sLAG3 was proved to have a higher diagnostic value than CEA in GC. Moreover, high sLAG-3 expression is found in relation to a better prognosis in GC. The in vivo experiments indicated that sLAG-3 might inhibit the tumor growth, and promote the secretion of CD8+T cells, IL-12 and IFN-γ. Furthermore, sLAG-3 was able to prolong overall survival and increase survival rate of GC-bearing mice. Based on these findings, we conclude that sLAG3 positively regulates CD8+T cells, IL-12 and IFN-γ, and function as a prognostic marker for GC, which might be a potential target in the treatment of GC.

A Critical Role for Intratumoral and Circulating LAG3 in Classical Hodgkin Lymphoma: Analysis from the Rathl Prospective Phase III International Clinical Trial

A Critical Role for Intratumoral and Circulating LAG3 in Classical Hodgkin Lymphoma: Analysis from the Rathl Prospective Phase III International Clinical Trial

Serum soluble lymphocyte activation gene-3 as a diagnostic biomarker in Parkinson's disease: A pilot multicenter study.

Lymphocyte activation gene-3 (LAG-3) could mediate pathological α-synuclein transmission in neurodegeneration and may be involved in the pathogenesis of Parkinson's disease (PD). The aim of the present study was to explore soluble LAG-3 (sLAG-3) as a potential diagnostic biomarker for PD. Serum sLAG-3 concentrations were measured by a quantitative ELISA for patients with PD, essential tremor (ET) and age- and sex-matched controls. The relationships between sLAG-3 and clinical phenotype were assessed via correlation analysis and logistic regression. Serum sLAG-3 levels in patients with PD were significantly higher than those in ET patients and age- and sex-matched controls. The area under the curve of serum sLAG-3 in differentiating PD from age- and sex-matched controls was 0.82. Serum sLAG-3 was associated with non-motor symptoms and excessive daytime sleep. sLAG-3 is a candidate novel biomarker for PD. © 2018 International Parkinson and Movement Disorder Society.

SLAG-3 in non-small-cell lung cancer patients' serum.

BackgroundAnti-programmed cell death-1/programmed cell death ligand-1 monoclonal antibodies have been widely used in non-small-cell lung cancer (NSCLC), but not every patient can get benefits from them. Whether other molecular markers can predict the results of programmed cell death-1/programmed cell death ligand-1 inhibitors need to be explored. Lymphocyte-activation gene-3 (LAG-3) is another important immune checkpoint, which can inhibit tumor immunity. Soluble LAG-3 (sLAG-3) plays different functions from LAG-3. In this study, we detected the serum sLAG-3 level in NSCLC patients.MethodssLAG-3 was detected in 247 hospitalized patients by enzyme-linked immunosorbent assay. Every sample was repeated three times.ResultsTwo-hundred forty-seven hospitalized patients were enrolled in this study. Of them, 71 had benign diseases and 176 were NSCLC patients. sLAG-3 in NSCLC serum was correlated with NSCLC stage. The sLAG-3 levels were significantly higher in stage I–II NSCLC than in stage III–IV (p<0.001).ConclusionThe advanced NSCLC had the lower sLAG-3 expression. This might be related to the poor cancer immune response. Increasing sLAG-3 level might be a promising treatment in advanced NSCLC patients.

Lymphocyte activation gene 3: a novel therapeutic target in chronic lymphocytic leukemia

A novel therapeutic approach in cancer, attempting to stimulate host anti-tumor immunity, involves blocking of immune checkpoints. Lymphocyte activation gene 3 (LAG3) is an immune checkpoint receptor expressed on activated/exhausted T cells. When engaged by the major histocompatibility complex (MHC) class II molecules, LAG3 negatively regulates T-cell function, thereby contributing to tumor escape. Intriguingly, a soluble LAG3 variant activates both immune and malignant MHC class II-presenting cells. In the study herein, we examined the role of LAG3 in the pathogenesis of chronic lymphocytic leukemia, an MHC class II-presenting malignancy, and show that chronic lymphocytic leukemia cells express and secrete LAG3. High levels of surface and soluble LAG3 were associated with the unmutated immunoglobulin variable heavy chain leukemic subtype and a shorter median time from diagnosis to first treatment. Utilizing a mechanism mediated through MHC class II engagement, recombinant soluble LAG3-Ig fusion protein, LAG3-Fc, activated chronic lymphocytic leukemia cells, induced anti-apoptotic pathways and protected the cells from spontaneous apoptosis, effects mediated by SYK, BTK and MAPK signaling. Moreover, LAG3 blocking antibody enhanced in vitro T-cell activation. Our data suggest that soluble LAG3 promotes leukemic cell activation and anti-apoptotic effects through its engagement with MHC class II. Furthermore, MHC class II-presenting chronic lymphocytic leukemia cells may affect LAG3-presenting T cells and impose immune exhaustion on their microenvironment; hence, blocking LAG3-MHC class II interactions is a potential therapeutic target in chronic lymphocytic leukemia.

Lymphocyte Activation Gene 3-a Novel Therapeutic Target in Chronic Lymphocytic Leukemia

A novel therapeutic approach in cancer attempting to stimulate host anti-tumor immunity involves blocking of immune checkpoints. Lymphocyte-activation gene 3 (LAG3) is an immune checkpoint receptor expressed on activated/exhausted T-cells. When engaged by MHC Class II (MHCII) molecules, LAG3 negatively regulates T-cell function thereby contributing to tumor escape. Intriguingly, a soluble LAG3 variant was reported to activate both immune and malignant MHCII-presenting cells. In this study, we examined the role of LAG3 in the pathogenesis of CLL and show that CLL cells express and secrete LAG3. High levels of surface and soluble LAG3 were associated with the unmutated immunoglobulin variable heavy chain CLL and a more aggressive disease. It was evident that recombinant soluble LAG3-Ig fusion protein activated CLL cells, induced increased levels of Bcl-2 and Mcl-1 and protected the cells from spontaneous apoptosis, utilizing a mechanism mediated through MHCII engagement. Our data suggest that autocrine secretion of soluble LAG3 from CLL cells and its subsequent interaction with MHCII on their surface, promotes CLL cell activation and anti-apoptotic effects. Moreover, CLL cells may impose immune exhaustion on their microenvironment by expressing MHCII, thus affecting the surrounding, LAG3-presenting immune cells. Hence, blocking LAG3-MHCII interactions is a potential therapeutic target in CLL. DisclosuresAvivi:Tel Aviv Sourasky Medical center: Consultancy, Other: consultancy to :BMS Roche. Wiestner:Pharmacyclics: Research Funding; Acerta Pharma: Research Funding.

Emerging immunotherapies for renal cell carcinoma

In recent years, an improved understanding of renal cell carcinoma (RCC) tumour biology has resulted in major advances in the treatment of patients with metastatic RCC (mRCC). Although immunotherapy with interleukin-2 and interferon-α was once the standard of care for mRCC, the introduction of novel agents targeting angiogenesis and signal transduction pathways has markedly improved patient outcomes. However, targeted agents rarely induce complete responses, and patients eventually develop resistance to therapy, prompting consideration of novel therapeutic approaches and a resurgence of interest in immunotherapy for RCC. Phase I/II trials of vaccination with allogeneic dendritic cell/tumour fusions in patients with mRCC have demonstrated immunological and clinical responses in some patients, and T-cell modulating agents (e.g. antibodies against programmed death 1 and cytotoxic T lymphocyte-associated antigen-4, or soluble lymphocyte activation gene-3) and dendritic cell-activating toll-like receptor agonists have also shown encouraging evidence of efficacy in early-phase clinical trials. These early studies suggest that immunotherapy may continue to be an effective approach for patients with mRCC. As such, a number of other strategies are currently under investigation, including adoptive cell transfer (ACT) with T cells modified to target proteins expressed by renal tumours such as MAGE-A3/12, DR4 and TRAIL, and ACT with autologous natural killer cells. Results from trials of novel immunotherapies are encouraging, with data from other indications helping to facilitate development. To realise the full benefit for patients, it is likely that immunotherapy will need to be combined with targeted agents or other agents. Novel therapies used in combination or sequentially have the potential to improve outcomes in mRCC, and results from ongoing/planned trials will shape future therapy.

Modulation of Redox Balance Leaves Murine Diabetogenic TH1 T Cells “LAG-3-ing” Behind

Preventing activation of diabetogenic T cells is critical for delaying type 1 diabetes onset. The inhibitory molecule lymphocyte activation gene 3 (LAG-3) and metalloprotease tumor necrosis factor-α converting enzyme (TACE) work together to regulate TH1 responses. The aim of this study was to determine if regulating redox using a catalytic antioxidant (CA) could modulate TACE-mediated LAG-3 shedding to impede diabetogenic T-cell activation and progression to disease. A combination of in vitro experiments and in vivo analyses using NOD mouse strains was conducted to test the effect of redox modulation on LAG-3 shedding, TACE enzymatic function, and disease onset. Systemic treatment of NOD mice significantly delayed type 1 diabetes onset. Disease prevention correlated with decreased activation, proliferation, and effector function of diabetogenic T cells; reduced insulin-specific T-cell frequency; and enhanced LAG-3+ cells. Redox modulation also affected TACE activation, diminishing LAG-3 cleavage. Furthermore, disease progression was monitored by measuring serum soluble LAG-3, which decreased in CA-treated mice. Therefore, affecting redox balance by CA treatment reduces the activation of diabetogenic T cells and impedes type 1 diabetes onset via decreasing T-cell effector function and LAG-3 cleavage. Moreover, soluble LAG-3 can serve as an early T-cell–specific biomarker for type 1 diabetes onset and immunomodulation.

MHC Class II Engagement by Its Ligand LAG-3 (CD223) Contributes to Melanoma Resistance to Apoptosis

Melanoma is the most aggressive skin cancer in humans that often expresses MHC class II (MHC II) molecules, which could make these tumors eliminable by the immune system. However, this MHC II expression has been associated with poor prognosis, and there is a lack of immune-mediated eradication. The lymphocyte activation gene-3 (LAG-3) is a natural ligand for MHC II that is substantially expressed on melanoma-infiltrating T cells including those endowed with potent immune-suppressive activity. Based on our previous data showing the signaling capacity of MHC II in melanoma cells, we hypothesized that LAG-3 could contribute to melanoma survival through its MHC II signaling capacity in melanoma cells. In this study, we demonstrate that both soluble LAG-3 and LAG-3-transfected cells can protect MHC II-positive melanoma cells, but not MHC II-negative cells, from FAS-mediated and drug-induced apoptosis. Interaction of LAG-3 with MHC II expressed on melanoma cells upregulates both MAPK/Erk and PI3K/Akt pathways, albeit with different kinetics. Inhibition studies using specific inhibitors of both pathways provided evidence of their involvement in the LAG-3-induced protection from apoptosis. Altogether, our data suggest that the LAG-3-MHC II interaction could be viewed as a bidirectional immune escape pathway in melanoma, with direct consequences shared by both melanoma and immune cells. In the future, compounds that efficiently hinder LAG-3-MHC II interaction might be used as an adjuvant to current therapy for MHC II-positive melanoma.