Soluble Form of T Cell Ig Mucin 3 Is an Inhibitory Molecule in T Cell-Mediated Immune Response

Serum soluble Tim‑3 is elevated in patients with cervical cancer and is higher in advanced clinical stages

T-cell immunoglobulin and mucin domain-containing protein-3 (Tim-3) is an immune checkpoint molecule that is expressed generally on the cell membrane of immune and cancer cells and is implicated as a negative regulator of anti-tumour immune responses; this occurs through the interaction of Tim-3 with galectin-9. Although the function of membrane Tim-3 is well known, the role of soluble Tim-3 (sTim-3) has been poorly explored. The aim of the present study was to compare the serum levels of sTim-3 in the cervical cancer group of patients vs. the control group, to determine the association between the serum levels of sTim-3 with the clinicopathological characteristics of patients with cervical cancer and with serum galectin-9 levels. The concentrations of serum sTim-3 and galectin-9 were determined using ELISA. A receiver operating characteristic (ROC) curve was performed to determine the diagnostic value of sTim-3. The Mann-Whitney and Kruskall-Wallis tests were used to compare the serum sTim-3 concentrations between the control and cervical cancer groups and among the clinical subgroups. The association between the concentrations of sTim-3 and galectin-9 was determined using Spearman's rank correlation coefficient. sTim-3 expression was higher in patients with cervical cancer compared with control patients. The ROC curve revealed that sTim-3 has diagnostic potential, with a specificity of 95% and a sensitivity of 85.19%. sTim-3 was higher in patients with International Federation of Gynaecology and Obstetrics (FIGO) stage IV compared with those with FIGO stages I, II and III. A moderate positive correlation (ρ=0.41) was identified between sTim-3 and galectin-9. This was the first report of changes in the serum concentrations of sTim-3 in patients with cervical cancer and their diagnostic value. The association between sTim-3 with cervical cancer progression, and the positive correlation between the serum concentrations of sTim-3 and galectin-9 suggested that both proteins might be involved in the immune dysregulation in cervical cancer, but this requires further exploration.

Clinical Value of Serum sTim-3, CEA, CA15-3 for Postoperative Recurrence of Breast Cancer

Objective

To evaluate the clinical value of serum soluble T cell immunoglobulin 3 (sTim-3) on postoperative recurrence of breast cancer (BC).

Methods

A highly sensitive time-resolved fluorescence immunoassay (TRFIA) was employed to measure sTim-3. Quantification of serum sTim-3 in 172 BC patients more than one-year postoperative (96 patients with stage I + II, 76 patients with stage III + IV; 31 patients with postoperative recurrence, and 141 patients with postoperative non-recurrence) and 51 healthy controls (HC). To evaluate the difference of serum sTim-3 in different stages of BC and its clinical value for postoperative recurrence of BC.

Results

The serum sTim-3 level of BC patients with stage III + IV (21.62 (17.27, 29.78)) were significantly higher than HC (4.49 (3.30, 7.60)), patients with stage I + II (14.96 + 4.94) (P < 0.0001). Serum sTim-3 level of BC patients with postoperative recurrence (21.8(12.40,34.20) were significantly higher than those without recurrence (17.13 ± 6.44) (P = 0.0130). When the serum sTim-3 level was below 11.8 ng/mL, the negative predictive values of sTim-3, CEA and CA15-3 were 90.9%, 68.0% and 67.1%, respectively, and the negative likelihood ratios were 0.16, 0.77 and 0.81, respectively. The positive rate of combined detection of sTim-3, CEA and CA15-3 was 58.1%, higher than single detection of CEA (22.6%) and CA15-3 (19.4%).

Conclusion

Serum sTim-3 levels may assist in the staging of BC. Combined detection of sTim-3, CEA, and CA15-3 can be used to routinely monitor the progression of BC and indicate the risk of postoperative BC recurrence.

Features and prognostic significance of soluble TIM-3 and its ligands Gal-9 and CEACAM1 levels in the diagnostic bone marrow of adult acute myeloid leukemia patients

The prognostic significance of soluble immune checkpoint molecule TIM-3 and its ligands in the plasma has been illustrated in various solid tumors, but such study in newly diagnosed acute myeloid leukemia (AML) remains absent. Soluble TIM-3, Gal-9, and CEACAM1 levels in bone marrow plasma samples collected from 90 adult AML patients at diagnosis and 12 healthy donors were measured by enzyme-linked immunosorbent assays, and 16 AML patients were simultaneously tested cell membrane TIM-3 expression by multicolor flow cytometry. AML patients had significantly elevated soluble TIM-3 levels and similar soluble Gal-9 and CEACAM1 levels compared with healthy donors (P = 0.0003, 0.26, and 0.96, respectively). In the whole cohort, a high soluble TIM-3 level was the sole independent adverse prognostic factor for relapse-free survival (RFS) (P = 0.0060), and together with adverse European LeukemiaNet genetic risk they were independent poor prognostic factors for event-free survival (P = 0.0030 and 0.0040, respectively). A high soluble CEACAM1 level was significantly related to lower RFS (P = 0.028). In addition, a high soluble Gal-9 level had a significant association with lower RFS in patients receiving allogeneic hematopoietic stem cell transplantation at the first complete remission (P = 0.037). Furthermore, soluble TIM-3 level tended to have positive correlation with the percentage of nonblast myeloid TIM-3+ cells in nucleated cells in AML (r = 0.48, P = 0.073). Therefore, the high soluble TIM-3 level in the diagnostic BM plasma predicted poor outcome in adult AML patients, and a high sGal-9 level was associated with relapse after allogeneic hematopoietic stem cell transplantation.

Soluble Tim-3 serves as a tumor prognostic marker and therapeutic target for CD8+ T cell exhaustion and anti-PD-1 resistance

Resistance to PD-1 blockade in onco-immunotherapy greatly limits its clinical application. T cell immunoglobulin and mucin domain containing-3 (Tim-3), a promising immune checkpoint target, is cleaved by ADAM10/17 to produce its soluble form (sTim-3) in humans, potentially becoming involved in anti-PD-1 resistance. Herein, serum sTim-3 upregulation was observed in non-small cell lung cancer (NSCLC) and various digestive tumors. Notably, serum sTim-3 is further upregulated in non-responding patients undergoing anti-PD-1 therapy for NSCLC and anti-PD-1-resistant cholangiocarcinoma patients. Furthermore, sTim-3 overexpression facilitates tumor progression and confers anti-PD-1 resistance in multiple tumor mouse models. Mechanistically, sTim-3 induces terminal T cell exhaustion and attenuates CD8+ T cell response to PD-1 blockade through carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAM-1). Moreover, the ADAM10 inhibitor GI254023X, which blocks sTim-3 production, reduces tumor progression in Tim-3 humanized mice and reverses anti-PD-1 resistance in human tumor-infiltrating lymphocytes (TILs). Overall, human sTim-3 holds great predictive and therapeutic potential in onco-immunotherapy.

Soluble form of immune checkpoints in autoimmune diseases

Immune checkpoints are essential regulators of immune responses, either by activating or suppressing them. Consequently, they are regarded as pivotal elements in the management of infections, cancer, and autoimmune disorders. In recent years, researchers have identified numerous soluble immune checkpoints that are produced through various mechanisms and demonstrated biological activity. These soluble immune checkpoints can be produced and distributed in the bloodstream and various tissues, with their roles in immune response dysregulation and autoimmunity extensively documented. This review aims to provide a thorough overview of the generation of various soluble immune checkpoints, such as sPD-1, sCTLA-4, sTim-3, s4-1BB, sBTLA, sLAG-3, sCD200, and the B7 family, and their importance as indicators for the diagnosis and prediction of autoimmune conditions. Furthermore, the review will investigate the potential pathological mechanisms of soluble immune checkpoints in autoimmune diseases, emphasizing their association with autoimmune diseases development, prognosis, and treatment.

Soluble immune checkpoints: implications for cancer prognosis and response to immune checkpoint therapy and conventional therapies

Longitudinal sampling of tumor tissue from patients with solid cancers, aside from melanoma and a few other cases, is often unfeasible, and thus may not capture the plasticity of interactions between the tumor and immune system under selective pressure of a given therapy. Peripheral blood analyses provide salient information about the human peripheral immunome while offering technical and practical advantages over traditional tumor biopsies, and should be utilized where possible alongside interrogation of the tumor. Some common blood-based biomarkers used to study the immune response include immune cell subsets, circulating tumor DNA, and protein analytes such as cytokines. With the recent explosion of immune checkpoint inhibitors (ICI) as a modality of treatment in multiple cancer types, soluble immune checkpoints have become a relevant area of investigation for peripheral immune-based biomarkers. However, the exact functions of soluble immune checkpoints and their roles in cancer for the most part remain unclear. This review discusses current literature on the production, function, and expression of nine soluble immune checkpoints - sPD-L1, sPD-1, sCTLA4, sCD80, sTIM3, sLAG3, sB7-H3, sBTLA, and sHVEM - in patients with solid tumors, and explores their role as biomarkers of response to ICI as well as to conventional therapies (chemotherapy, radiotherapy, targeted therapy, and surgery) in cancer patients.

Deciphering the role of alternative splicing in neoplastic diseases for immune-oncological therapies

Alternative splicing (AS) is an important molecular biological mechanism regulated by complex mechanisms involving a plethora of cis and trans-acting elements. Furthermore, AS is tissue specific and altered in various pathologies, including infectious, inflammatory, and neoplastic diseases. Recently developed immuno-oncological therapies include monoclonal antibodies (mAbs) and chimeric antigen receptor (CAR) T cells targeting, among others, immune checkpoint (ICP) molecules. Despite therapeutic successes have been demonstrated, only a limited number of patients showed long-term benefit from these therapies with tumor entity-related differential response rates were observed. Interestingly, splice variants of common immunotherapeutic targets generated by AS are able to completely escape and/or reduce the efficacy of mAb- and/or CAR-based tumor immunotherapies. Therefore, the analyses of splicing patterns of targeted molecules in tumor specimens prior to therapy might help correct stratification, thereby increasing therapy success by antibody panel selection and antibody dosages. In addition, the expression of certain splicing factors has been linked with the patients' outcome, thereby highlighting their putative prognostic potential. Outstanding questions are addressed to translate the findings into clinical application. This review article provides an overview of the role of AS in (tumor) diseases, its molecular mechanisms, clinical relevance, and therapy response.

Loss of ADAR1 in macrophages in combination with interferon gamma suppresses tumor growth by remodeling the tumor microenvironment

BACKGROUND

ADAR1, the major enzyme for RNA editing, has emerged as a tumor-intrinsic key determinant for cancer immunotherapy efficacy through modulating interferon-mediated innate immunity. However, the role of ADAR1 in innate immune cells such as macrophages remains unknown.

METHODS

We first analyzed publicly accessible patient-derived single-cell RNA-sequencing and perturbed RNA sequencing data to elucidate the ADAR1 expression and function in macrophages. Subsequently, we evaluated the combined effects of ADAR1 conditional knockout in macrophages and interferon (IFN)-γ treatment on tumor growth in three distinct disease mouse models: LLC for lung cancer, B16-F10 for melanoma, and MC38 for colon cancer. To gain the mechanistic insights, we performed human cytokine arrays to identify differentially secreted cytokines in response to ADAR1 perturbations in THP-1 cells. Furthermore, we examined the effects of ADAR1 loss and IFN-γ treatment on vessel formation through immunohistochemical staining of mouse tumor sections and tube-forming experiments using HUVEC and SVEC4-10 cells. We also assessed the effects on CD8+ T cells using immunofluorescent and immunohistochemical staining and flow cytometry. To explore the translational potential, we examined the consequences of injecting ADAR1-deficient macrophages alongside IFN-γ treatment on tumor growth in LLC-tumor-bearing mice.

RESULTS

Our analysis on public data suggests that ADAR1 loss in macrophages promotes antitumor immunity as in cancer cells. Indeed, ADAR1 loss in macrophages combined with IFN-γ treatment results in tumor regression in diverse disease mouse models. Mechanistically, the loss of ADAR1 in macrophages leads to the differential secretion of key cytokines: it inhibits the translation of CCL20, GDF15, IL-18BP, and TIM-3 by activating PKR/EIF2α signaling but increases the secretion of IFN-γ through transcriptional upregulation and interleukin (IL)-18 due to the 5'UTR uORF. Consequently, decreased CCL20 and GDF15 and increased IFN-γ suppress angiogenesis, while decreased IL-18BP and TIM-3 and increased IL-18 induce antitumor immunity by enhancing cytotoxicity of CD8+ T cells. We further demonstrate that combination therapy of injecting ADAR1-deficient macrophages and IFN-γ effectively suppresses tumors in vivo.

CONCLUSION

This study provides a comprehensive elucidation of how ADAR1 loss within macrophages contributes to the establishment of an antitumor microenvironment, suggesting the therapeutic potential of targeting ADAR1 beyond the scope of cancer cells.

Tim-3 Is Differentially Expressed during Cell Activation and Interacts with the LSP-1 Protein in Human Macrophages

T-cell Immunoglobulin and Mucin Domain 3 (TIM-3) is an immune checkpoint receptor known to regulate T-cell activation and has been targeted for immunotherapy in cancer and other diseases. However, its expression and function in other cell types, such as macrophages, are poorly understood. This study investigated TIM-3 expression in human macrophages polarized to M1 (stimulated with IFN-γ and LPS) and M2 (stimulated with IL-4 and IL-13) phenotypes using an in vitro model. Our results show that M1 macrophages have a lower frequency of TIM-3+ cells compared to M2 macrophages at 48 and 72 hr poststimulation. Additionally, we observed differential levels of soluble ADAM 10, an enzyme responsible for TIM-3 release, in the supernatants of M1 and M2 macrophages at 72 hr. We also found that the TIM-3 intracellular tail might associate with lymphocyte-specific protein 1 (LSP-1), a protein implicated in cell motility and podosome formation. These findings enhance our understanding of TIM-3 function in myeloid cells such as macrophages and may inform the development of immunotherapies with reduced immune-related adverse effects.

Targeting LAG-3, TIM-3, and TIGIT for cancer immunotherapy

In one decade, immunotherapy based on immune checkpoint blockades (ICBs) has become a new pillar of cancer treatment following surgery, radiation, chemotherapy, and targeted therapies. However, not all cancer patients benefit from single or combination therapy with anti-CTLA-4 and anti-PD-1/PD-L1 monoclonal antibodies. Thus, an increasing number of immune checkpoint proteins (ICPs) have been screened and their effectiveness evaluated in preclinical and clinical trials. Lymphocyte activation gene-3 (LAG-3), T cell immunoglobulin and mucin-domain-containing-3 (TIM-3), and T cell immunoreceptor with immunoglobulin and tyrosine-based inhibitory motif (ITIM) domain (TIGIT) constitute the second wave of immunotherapy targets that show great promise for use in the treatment of solid tumors and leukemia. To promote the research and clinical application of ICBs directed at these targets, we summarize their discovery, immunotherapy mechanism, preclinical efficiency, and clinical trial results in this review.

Serum soluble immune checkpoint levels predict cervical lymph node metastasis of differentiated thyroid carcinoma patients

BACKGROUND

Cervical lymph node metastasis (CLNM) is common in patients with differentiated thyroid carcinoma (DTC); however, the efficiency to distinguish CLNM before surgery is limited. T cell exhaustion, characterized by the overexpression of immune checkpoints, plays a critical role in the immune evasion of tumors. The aim of this study is to analyze the association between serum levels of soluble immune checkpoints (sICs) and CLNM in DTC patients.

METHODS

Levels of sICs in serum of 71 DTC patients and 56 healthy volunteers were analyzed by ELISA. Peripheral blood mononuclear cells and cervical lymph nodes of DTC patients were isolated and their expression of sICs were analyzed. Lymphocytes in cervical lymph nodes were analyzed for immune checkpoints expression and transcription of exhaustion-associated factors. 30 out of 71 DTC patients were followed up from 3 to 9 months after the operation, and postoperative sTIM-3 were analyzed.

RESULTS

Four sICs, including LAG-3, PD-1, PD-L1, and TIM-3, were increased in DTC patients. All four sICs exhibited higher sensitivity at discriminating CLNM than cervical ultrasound. In the patient-matched comparison, higher sTIM-3 levels were observed in tumor-involved lymph nodes (TILNs) than in normal lymph nodes (nLNs). T lymphocytes in TILNs had higher TIM-3 surface expression and increased secretion of sTIM-3 than those in patient-matched nLNs. Finally, postoperative serum sTIM-3 levels were decreased in DTC patients with CLNM compared to their preoperative levels.

CONCLUSION

Serum levels of sICs, especially sTIM-3, could help to predict CLNM and provide evidence for surgical decision-making in DTC.

Soluble immune checkpoints as correlates for HIV persistence and T cell function in people with HIV on antiretroviral therapy

Introduction

In people with HIV (PWH) both off and on antiretroviral therapy (ART), the expression of immune checkpoint (IC) proteins is elevated on the surface of total and HIV-specific T-cells, indicating T-cell exhaustion. Soluble IC proteins and their ligands can also be detected in plasma, but have not been systematically examined in PWH. Since T-cell exhaustion is associated with HIV persistence on ART, we aimed to determine if soluble IC proteins and their ligands also correlated with the size of the HIV reservoir and HIV-specific T-cell function.

Methods

We used multiplex bead-based immunoassay to quantify soluble programmed cell death protein 1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), lymphocyte activation gene-3 (LAG-3), T cell immunoglobulin domain and mucin domain 3 (TIM-3), PD-1 Ligand 1 (PD-L1) and PD-1 Ligand 2 (PD-L2) in plasma from PWH off ART (n=20), on suppressive ART (n=75) and uninfected controls (n=20). We also quantified expression of membrane-bound IC and frequencies of functional T-cells to Gag and Nef peptide stimulation on CD4+ and CD8+ T-cells using flow cytometry. The HIV reservoir was quantified in circulating CD4+ T-cells using qPCR for total and integrated HIV DNA, cell-associated unspliced HIV RNA and 2LTR circles.

Results

Soluble (s) PD-L2 level was higher in PWH off and on ART compared to uninfected controls. Higher levels of sPD-L2 correlated with lower levels of HIV total DNA and higher frequencies of gag-specific CD8+ T-cells expressing CD107a, IFNγ or TNFα. In contrast, the concentration of sLAG-3 was similar in uninfected individuals and PWH on ART, but was significantly elevated in PWH off ART. Higher levels of sLAG-3 correlated with higher levels of HIV total and integrated DNA, and lower frequency of gag-specific CD4+ T cells expressing CD107a. Similar to sLAG-3, levels of sPD-1 were elevated in PWH off ART and normalized in PWH on ART. sPD-1 was positively correlated with the frequency of gag-specific CD4+ T cells expressing TNF-a and the expression of membrane-bound PD-1 on total CD8+ T-cells in PWH on ART.

Discussion

Plasma soluble IC proteins and their ligands correlate with markers of the HIV reservoir and HIV-specific T-cell function and should be investigated further in in large population-based studies of the HIV reservoir or cure interventions in PWH on ART.

Soluble TIM-3 as a biomarker of progression and therapeutic response in cancers and other of human diseases

Immune checkpoints inhibition is a privileged approach to combat cancers and other human diseases. The TIM-3 (T cell immunoglobulin and mucin-domain containing-3) inhibitory checkpoint expressed on different types of immune cells is actively investigated as an anticancer target, with a dozen of monoclonal antibodies in (pre)clinical development. A soluble form sTIM-3 can be found in the plasma of patients with cancer and other diseases. This active circulating protein originates from the proteolytic cleavage by two ADAM metalloproteases of the membrane receptor shared by tumor and non-tumor cells, and extracellular vesicles. In most cancers but not all, overexpression of mTIM-3 at the cell surface leads to high level of sTIM-3. Similarly, elevated levels of sTIM-3 have been reported in chronic autoimmune diseases, inflammatory gastro-intestinal diseases, certain viral and parasitic diseases, but also in cases of organ transplantation and in pregnancy-related pathologies. We have analyzed the origin of sTIM-3, its methods of dosage in blood or plasma, its presence in multiple diseases and its potential role as a biomarker to follow disease progression and/or the treatment response. In contrast to sPD-L1 generated by different classes of proteases and by alternative splicing, sTIM-3 is uniquely produced upon ADAM-dependent shedding, providing a more homogenous molecular entity and a possibly more reliable molecular marker. However, the biological functionality of sTIM-3 remains insufficiently characterized. The review shed light on pathologies associated with an altered expression of sTIM-3 in human plasma and the possibility to use sTIM-3 as a diagnostic or therapeutic marker.

The imbalance of liver resident macrophages polarization promotes chronic autoimmune hepatitis development in mice

Background

Autoimmune hepatitis (AIH) is a chronic immune-mediated inflammatory liver disease. At present, it is largely unknown how the innate immune cells influence AIH development.

Objective

To inquiry about mechanism of liver resident macrophages in AIH development, thus offering a new direction for AIH targeted treatment.

Methods

The liver resident macrophages were eliminated by clodronate liposomes in AIH liver tissues, followed by HE and Picrosirius assay to detect liver fibrosis and lymphocyte infiltration. The liver resident macrophages polarization was detected by Immunohistochemistry and qPCR. The collagenase digestion was used to isolate Kupffer cells from AIH mice liver tissues and pro-/anti-inflammatory cytokines were determined by qPCR.

Results

M2 macrophages were the dominant phenotype at early immune response stage and hepatic inflammation was progressively aggravated after depletion of liver resident macrophages. M2 macrophages could effectively delay the development of AIH and could be polarized to M1 macrophages at the disease progresses. TLR2 ligands could promote M2 macrophages producing anti-inflammatory cytokines, whereas TLR4 ligands could promote M1 macrophages producing proinflammatory cytokines. The change of TLR2 and TLR4 ligands could lead to continuous high expression of TLR4 and decreased expression of TLR2 in macrophages to further affect liver resident macrophages polarization state.

Conclusion

TLR2 and TLR4 ligands mediated liver resident macrophages polarization to favor chronic autoimmune hepatitis development.

Biomarkers for early complications post hematopoietic cell transplantation: Insights and challenges

Hematopoietic cell transplantation is an established curative treatment option for various hematological malignant, and non-malignant diseases. However, the success of HCT is still limited by life-threatening early complications post-HCT, such as Graft Versus Host Disease (GVHD), Sinusoidal Obstruction Syndrome (SOS), and transplant-associated microangiopathy, to name a few. A decade of research in the discovery and validation of novel blood-based biomarkers aims to manage these early complications by using them for diagnosis or prognosis. Advances in this field have also led to predictive biomarkers to identify patients' likelihood of response to therapy. Although biomarkers have been extensively evaluated for different complications, these are yet to be used in routine clinical practice. This review provides a detailed summary of various biomarkers for individual early complications post-HCT, their discovery, validation, ongoing clinical trials, and their limitations. Furthermore, this review also provides insights into the biology of biomarkers and the challenge of obtaining a universal cut-off value for biomarkers.

Prognostic Role of Serum Soluble Tim-3 in Severe Traumatic Brain Injury: A Prospective Observational Study

OBJECTIVE

T cell immunoglobulin and mucin domain-3 (Tim-3) may be implicated in neuroinflammation. Herein, we attempted to discern the role of serum soluble (s) Tim-3 as an inflammatory prognostic biomarker of severe traumatic brain injury (sTBI).

METHODS

In this prospective observational study of 112 sTBI patients and 112 controls, serum sTim-3 levels were determined, Rotterdam computed tomography (CT) classification and Glasgow coma scale (GCS) were selected as the two severity indicators, serum C-reactive protein (CRP) was regarded as an inflammatory biomarker, and poor prognosis was referred to as extended Glasgow outcome scale (GOSE) scores 1-4 at 180 days after trauma.

RESULTS

Serum sTim-3 levels were markedly higher in patients than in controls (median, 4.2 ng/mL versus 0.7 ng/mL; P<0.001). Serum sTim-3 levels of patients were independently related to Rotterdam CT scores (β=1.126), GCS scores (β=-0.589), serum CRP levels (β=0.155) and GOSE scores (β=-0.211). Serum sTim-3 appeared as an independent predictor of post-traumatic 180-day mortality (odds ratio=1.289), overall survival (hazard ratio=1.208) and poor prognosis (odds ratio=1.293). Serum sTim-3 levels discriminated patients at risk of post-injury 180-day mortality and poor prognosis with areas under curve (AUCs) at 0.753 and 0.782, respectively. Serum sTim-3 levels combined with GCS scores and Rotterdam CT scores (AUC=0.869) exhibited significantly higher AUC than Rotterdam CT scores (P=0.026), but not than GCS scores (P=0.181) for death prediction and their combination (AUC=0.895) had significantly higher AUC than GCS scores (P=0.036) or Rotterdam CT scores (P=0.005) for outcome prediction.

CONCLUSION

Elevated serum sTim-3 levels, in close correlation with traumatic severity and inflammation, are substantially associated with long-term death and poor outcome, indicating that serum sTim-3, as an inflammatory biomarker, may be of clinical significance in severity assessment and prediction of prognosis following sTBI.

Immune system-related soluble mediators and COVID-19: basic mechanisms and clinical perspectives

During SARS-CoV-2 infection, an effective immune response provides the first line of defense; however, excessive inflammatory innate immunity and impaired adaptive immunity may harm tissues. Soluble immune mediators are involved in the dynamic interaction of ligands with membrane-bound receptors to maintain and restore health after pathological events. In some cases, the dysregulation of their expression can lead to disease pathology. In this literature review, we described current knowledge of the basic features of soluble immune mediators and their dysregulation during SARS-CoV-2 infections and highlighted their contribution to disease severity and mortality.

Increase in Serum Soluble Tim-3 Level Is Related to the Progression of Diseases After Hepatitis Virus Infection

Background

Viral hepatitis is a widespread and serious infectious disease, and most patients with liver cirrhosis and hepatocellular carcinoma are prone to viral infections. T cell immunoglobulin-and mucin-domain-containing molecule-3 (Tim-3) is an immune checkpoint molecule that negatively regulates T cell responses, playing an extremely important role in controlling infectious diseases. However, reports about the role of serum soluble Tim-3 (sTim-3) in hepatitis virus infection are limited. Therefore, this study explored changes in sTim-3 levels in patients infected with hepatitis B virus (HBV), hepatitis C virus (HCV), and hepatitis E virus (HEV).

Methods

This study applied high-sensitivity time-resolved fluorescence immunoassay for the detection of sTim-3 levels. A total of 205 cases of viral hepatitis infection (68 cases of HBV infection, 60 cases of HCV infection, and 77 cases of HEV virus infection) and 88 healthy controls were quantitatively determined. The changes in serum sTim-3 level and its clinical value in hepatitis virus infection were analyzed.

Results

Patients with HBV infection (14.00, 10.78–20.45 ng/mL), HCV infection (15.99, 11.83–27.00 ng/mL), or HEV infection (19.09, 10.85–33.93 ng/mL) had significantly higher sTim-3 levels than that in the healthy control group (7.69, 6.14–10.22 ng/mL, P &lt; 0.0001). Patients with hepatitis and fibrosis infected with HBV (22.76, 12.82–37.53 ng/mL), HCV (33.06, 16.36–39.30 ng/mL), and HEV (28.90, 17.95–35.94 ng/mL) had significantly higher sTim-3 levels than patients with hepatitis without fibrosis (13.29, 7.75–17.28; 13.86, 11.48–18.64; 14.77, 9.79–29.79 ng/mL; P &lt; 0.05).

Conclusion

sTim-3 level was elevated in patients infected with HBV, HCV, or HEV and gradually increased in patients with either hepatitis or hepatitis with hepatic fibrosis. It has a certain role in the evaluation of the course of a disease after hepatitis virus infection.

Moscatilin suppresses the inflammation from macrophages and T cells

In this study, we aim to investigate moscatilin in alleviating symptoms of autoimmune liver disease (ALD) in a concanavalin A (ConA)-induced liver injury mouse model and elucidate the underlying mechanisms. ALD mouse models were constructed by intravenous injection of ConA (20 mg/kg) and the serum level of alanine aminotransferase (ALT) was measured using an enzyme-linked immunosorbent assay. Moscatilin in various doses was administered for two days starting from a day before the ConA injection. We showed that moscatilin dose-dependently decreased ALT levels in liver tissue of ALD mouse models. Ifng and Tnfa also showed significant downregulation in liver tissues. Macrophages only showed significant Tnfa downregulation and CD4⁺ T cells only showed significant Ifng downregulation at high moscatilin doses. In vivo administration of moscatilin induced interleukin-37 upregulation in hepatic tissues. In vitro, moscatilin also induced IL-37 upregulation in hepatic stellate cell line JS-1 rather than immune cells represented by RAW264.7 and CTLL-2 cell lines, suggesting that the hepatic stellate cell is majorly responsive to moscatilin treatment in terms of interleukin (IL)-37 upregulation. Our data indicate that moscatilin could alleviate liver injury in ConA-induced ALD mouse models through anti-inflammatory activities, warranting further development of moscatilin as a new drug in treating ALD.

Potential diagnostic and prognostic of efferocytosis-related unwanted soluble receptors/ligands as new non-invasive biomarkers in disorders: a review

Efferocytosis is the process by which apoptotic cells are removed without inflammation to maintain tissue homeostasis, prevent unwanted inflammatory responses, and inhibit autoimmune responses. Coordination of efferocytosis occurs via many surfaces and chemotactic molecules and adaptors. Recently, soluble positive or negative mediators of efferocytosis, have been more noticeable as non-invasive valuable biomarkers in prognosis and targeted therapy. These soluble factors can be detected in different bodily fluids, such as serum, plasma, and urine as a non-invasive method. There are lots of studies that have tried to show the importance of receptors and ligands in disorders; while a few studies tried to indicate the importance of soluble forms of receptors/ligands and their clinical aspects as a systemic compound and shedding of targets related to efferocytosis. Some of these soluble forms also can be as sensitive as specific biomarkers for certain diseases compared with routine biomarkers, such as soluble circulatory Lectin-like oxidized low-density lipoprotein receptor-1 vs. troponin T in the acute coronary syndrome. Thus, this review tried to gain more understanding about efferocytosis-related unwanted soluble receptors/ligands, their roles, the clinical significance, and potential for diagnosis, and prognosis related to different diseases.

The role of A Disintegrin and Metalloproteinase (ADAM)-10 in T helper cell biology

A Disintegrin and Metalloproteinases (ADAM)-10 is a member of a family of membrane-anchored proteinases that regulate a broad range of cellular functions with central roles within the immune system. This has spurred the interest to modulate ADAM activity therapeutically in immunological diseases. CD4 T helper (Th) cells are the key regulators of adaptive immune responses. Their development and function is strongly dependent on Notch, a key ADAM-10 substrate. However, Th cells rely on a variety of additional ADAM-10 substrates regulating their functional activity at multiple levels. The complexity of both, the ADAM substrate expression as well as the functional consequences of ADAM-mediated cleavage of the various substrates complicates the analysis of cell type specific effects. Here we provide an overview on the major ADAM-10 substrates relevant for CD4 T cell biology and discuss the potential effects of ADAM-mediated cleavage exemplified for a selection of important substrates.

TIM-3 shuttled by MV3 cells-secreted exosomes inhibits CD4+ T cell immune function and induces macrophage M2 polarization to promote the growth and metastasis of melanoma cells

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MV3-Exo inhibits CD4⁺ t cell immune function and induces M2-polarized macrophages.

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TIM-3 is upregulated in MV3 cells-secreted exosomes.

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TIM-3 inhibits CD4⁺ t cell immune function and induces M2-polarized macrophages.

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TIM-3 shuttled by MV3-Exo promotes growth and metastasis of melanoma.

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The study unveiled a protective target against metastasis of melanoma.

This study is sought to determine the physiological mechanisms by which exosomes-encapsulated TIM-3 derived from melanoma cells might mediate CD4⁺ T cell immune function and macrophage M2 polarization in melanoma. Initially, exosomes were isolated from the human skin-derived melanoma cell line MV3for analysis of TIM-3 expression pattern. Next, the exosomes sourced from MV3 cells manipulated with sh-TIM-3 were co-incubated with CD4⁺ T cells to detect CD4⁺ T cell proliferation and MV3 cell migration and invasion, to observe the macrophage M2 polarization, and to determine levels of several EMT-related factors. Finally, melanoma nude mouse models were established to study the in vivo modulatory effects of TIM-3 from MV3 cells-derived exosomes. MV3 cells-derived exosomes inhibited CD4⁺ T cell immune function and promoted macrophage M2 polarization in melanoma. Our results revealed the abundance of TIM-3 in MV3 cells-derived exosomes. Of importance, silencing of TIM-3 shuttled by MV3 cells-derived exosomes improved CD4⁺ T cell immune function and inhibited macrophage M2 polarization to attenuate the growth and metastasis of melanoma cells. Collectively, MV3 cells-derived exosomes-loaded TIM-3 suppressed CD4⁺ T cell immune function and induced macrophage M2 polarization to improve occurrence and development of melanoma, therefore providing us with a potential therapeutic target for effectively combating melanoma.

A comprehensive profiling of soluble immune checkpoints from the sera of patients with non-small cell lung cancer

BACKGROUND

Immunotherapy was widely used for the treatment of non-small cell lung cancer (NSCLC). However, whether inhibition of immune checkpoints individually or simultaneously could improve the therapeutic efficacy of NSCLC remains to be investigated. Here, we explored the aberrant levels of several checkpoints and evaluated their potential diagnostic values for NSCLC.

METHODS

Serum samples of 89 NSCLC patients and 57 healthy donors were collected from Nanjing Drum Tower Hospital between November 2019 and July 2020. Fourteen human immune checkpoints were quantified by Procarta-Plex Human Immuno-Oncology Checkpoint Panel.

RESULTS

The expression levels of sTIM-3, sCD137, sCD27, sLAG-3, sIDO, sPD-L2, sCD152, sCD80, and sPD-1 were all significantly increased in serum of NSCLC patients. Especially, sLAG-3 was significantly elevated in serum of NSCLC patients at early-stage (stages I and II), TIM-3, CD137, and CD27 were significantly higher in the advanced NSCLC patients (stages III and IV) than in the early-stage groups. Receiver operating characteristics (ROC) results showed that except for PD-1, all the other immune checkpoint proteins had potential diagnostic values for NSCLC. sTIM-3 had the highest diagnostic accuracy, followed by sLAG-3. Combining sTIM-3, sLAG-3, and sCD137 could increase the accuracy to a higher level. Moreover, sCD27 was correlated with NSCLC cancer type, age, sex, and disease stage, while sCD137 was correlated with age and disease stage. sTIM-3 and sIDO were correlated with stage and age, respectively.

CONCLUSIONS

TIM-3 and LAG-3 were independent biomarkers for the early diagnosis of NSCLC. The combination of TIM-3, LAG-3, and CD137 could increase the diagnostic accuracy.

Soluble T cell immunoglobulin and mucin-domain containing protein 3 in children hospitalized with pneumonia in resource-limited settings

In a prospective cohort study of 77 children with severe pneumonia from two hospitals in Uganda, we assessed soluble T cell immunoglobulin and mucin-domain containing protein 3 (sTIM-3) levels at hospital admission and their association with pneumonia severity and subsequent mortality. sTIM-3 levels were positively correlated with the Respiratory Index of Severity in Children (RISC) (ρ = 0.35, p = 0.0017), sTIM-3 levels were higher in children who required transfer to a tertiary hospital (p = 0.014) and in fatal cases (p = 0.011). In summary, sTIM-3 is associated with disease severity and predictive of mortality in childhood pneumonia in resource-limited settings.

Soluble Tim-3/Gal-9 as predictors of adverse outcomes after kidney transplantation: a cohort study

BACKGROUND

In our previous study, serum soluble T-cell immunoglobulin and mucin structure-3 (stim-3) and galactosin-9 (sGal-9) were found to be associated with renal function after kidney transplantation. However, it is unclear whether these two indicators can predict adverse outcomes after transplantation.

METHODS

Ninety-one recipients of kidney transplantation were enrolled and divided into a stable group and an adverse outcome group (consisting of biopsy-proven rejection, graft loss, death and clinically diagnosed rejection). The expression levels of sTim-3 and sGal-9 before (pre-Tim-3 and pre-Gal-9) and one month after transplantation (post-Tim-3 and post-Gal-9) were measured by ELISA.

RESULTS

The level of pre-Tim-3 was significantly higher in the stable group than in the adverse outcome group [median (range), 2275 (840-4236) pg/mL vs. 1589 (353-3094) pg/mL, P=0.002]. The level of post-Gal-9 was significantly lower in the stable group than in the adverse outcome group [median (range), 4869 (1418-13080) pg/mL vs. 6852: (4128-10760) pg/mL, P=0.003]. The areas under the curve (AUCs) for pre-Tim-3 and post-Gal-9 were 0.737 (P=0.002) and 0.751 (P=0.003), respectively, better than AUC of post-eGFR (0.633) (P=0.071), according to the receiver operating characteristic (ROC) curve. Through Cox regression analysis, including pre-Tim-3, post-Gal-9, post-eGFR, sex, age, BMI of recipients and donors, pre-Tim-3 and post-Gal-9 were independent risk factors for adverse outcomes after kidney transplantation (P=0.016, P=0.033, respectively).

CONCLUSION

Serum sTim-3 and sGal-9 can predict adverse outcomes within two years after kidney transplantation.

G-CSF and IL-6 may be involved in formation of endometriosis lesions by increasing the expression of angiogenic factors in neutrophils

Evidence accumulated in recent years has revealed that neutrophils are involved in the initial establishment of endometriosis, which is well-known as a chronic inflammatory disease. So far, why and how neutrophils promote the formation of early endometriosis are still unclear. In this study, using a mouse model of endometriosis, we demonstrated that endometriosis mice (EMs mice) had a significantly increased number of neutrophils in peritoneal fluids and lesions, and increased levels of granulocyte colony-stimulating factor (G-CSF) and IL-6 in serum and peritoneal fluids compared to the control group. In the neutrophils and uterine fragments co-injection experiment, neutrophils regulated by G-CSF and IL-6 had a similar effect to neutrophils from EMs mice, increasing the number, area, weight and microvessel density (MVD) of endometriotic lesions. Blocking the effect of G-CSF and IL-6 in EMs mice resulted in a decrease in the number, area and weight of endometriotic lesions. Following the depletion of neutrophils in vivo using a anti-Ly6G antibody, the MVD in the lesions of mice treated with neutrophils from EMs mice and neutrophils from pG/pI6 mice were significantly reduced. Neutrophils from EMs mice and neutrophils from pG/pI6 mice altered the expression levels of Mmp9, Bv8 and Trail genes compared to the neutrophils from PBS-treated mice. IL-6 together with G-CSF induced a higher expression of phospho-STAT3 and STAT3 in neutrophils. These findings suggest that neutrophils modulated by G-CSF and IL-6 through the STAT3 pathway alter the expression levels of the angiogenesis-related genes Mmp9, Bv8 and Trail, and may promote the establishment of early endometriosis.

Clinical Value of Combined Detection of Serum sTim-3 and Pepsinogen for Gastric Cancer Diagnosis

Purpose

The present study aimed to evaluate the clinical value of the combined detection of soluble T cell immunoglobulinand mucin domain molecule 3 (sTim-3) and pepsinogen (PG) in sera for gastric cancer (GC) diagnosis.

Patients and Methods

The double antibody sandwich method was used to establish a highly sensitive time-resolved fluorescence immunoassay for the detection of sTim-3. Serum sTim-3, PGI, and PGII levels in 149 GC patients (123 first-diagnosis GC patients and 26 post-GC patients), 81 patients with benign gastric disease (BGD), and 73 healthy controls were quantitatively detected. The clinical diagnostic value of the combined detection of sTim-3 and PG in GC was analyzed.

Results

Serum sTim-3 levels in GC (20.41 ± 9.55 ng/mL) and BGD (16.50 ± 9.76 ng/mL) patients were significantly higher (P < 0.001) than those in healthy controls (9.22 ± 3.40 ng/mL). Combined detection of sTim-3 and PGI/PGII (AUC: 0.9330, sensitivity: 86.44%, and specificity: 91.78%) showed a high diagnostic value for GC. When the level of PGI/PGII was less than 12.11 and that of sTim-3 was greater than 14.30 ng/mL, the positive rate of the control group was reduced to 0%, and the positive detection rate of GC was 54.47%. In addition, in post-operative patients, serum sTim-3 levels in the recurrence group (33.56 ± 4.91 ng/mL) were significantly higher than those in the no recurrence group (11.95 ± 5.16 ng/mL).

Conclusion

sTim-3 levels in BGD and GC sera were significantly higher than those in the control group sera. Additionally, sTim-3 serum levels can predict recurrence in post-operative patients. Compared with PG alone, the combined detection of serum PG and sTim-3 can significantly improve the detection sensitivity and specificity of BGD and GC.

Patients With Microscopic Colitis Have Altered Levels of Inhibitory and Stimulatory Biomarkers in Colon Biopsies and Sera Compared to Non-inflamed Controls

Introduction: Microscopic colitis (MC) is an inflammatory bowel condition with two subtypes, lymphocytic colitis (LC) and collagenous colitis (CC). Unlike patients with ulcerative colitis (UC) and non-inflamed individuals, MC patients have reduced risk of developing colorectal cancer, possibly due to increased immune surveillance in MC patients. Aim: To examine differences in levels of immunomodulatory molecules, including those involved in immune checkpoint mechanisms, in sera from patients with MC and in colonic biopsies from patients with MC and UC compared with controls. Methods: Using Luminex, 23 analytes (4-1BB, 4-1BBL, APRIL, BAFF, BTLA, CD27, CD28, CD80, CTLA-4, E-cadherin, Galectin-3, GITR, HVEM, IDO, IL-2Rα, LAG-3, MICA, MICB, PD-1, PD-L1, PD-L2, sCD40L and TIM-3) were studied in serum from patients with active MC (n = 35) and controls (n = 23), and in colonic biopsies from patients with active LC (n = 9), active CC (n = 16) and MC in histological remission (LC n = 6, CC n = 6), active UC (n = 15) and UC in remission (n = 12) and controls (n = 58). Results: In serum, IDO, PD-1, TIM-3, 4-1BB, CD27, and CD80 were decreased whereas 4-1BBL and IL-2Rα were increased in MC patients compared with controls. In contrast, in biopsies, levels of PD-L2 and 4-1BB were increased in MC and UC patients with active disease. Furthermore, in biopsies from CC and UC but not LC patients with active disease, CTLA-4, PD-1, APRIL, BAFF, and IL-2Rα were increased compared with controls. PD-L1 was increased in CC but not UC or LC patients. CD27 and TIM-3 were decreased in biopsies from MC patients in comparison to controls whereas levels of MICB were decreased in patients with active UC compared with controls. Conclusions: Compared with non-inflamed controls, levels of soluble and membrane-bound immunomodulatory molecules were systemically and locally altered in MC and UC patients, with most analytes being decreased in serum but enhanced in colonic biopsies. These findings contribute to knowledge about checkpoint molecules and their role as biomarkers in MC and may also contribute to knowledge about possible mechanisms behind the seemingly protective effects of MC against colorectal cancer.

The HIV-1 accessory protein Nef increases surface expression of the checkpoint receptor Tim-3 in infected CD4+ T cells

Prolonged immune activation drives the upregulation of multiple checkpoint receptors on the surface of virus-specific T cells, inducing their exhaustion. Reversing HIV-1-induced T cell exhaustion is imperative for efficient virus clearance; however, viral mediators of checkpoint receptor upregulation remain largely unknown. The enrichment of checkpoint receptors on T cells upon HIV-1 infection severely constrains the generation of an efficient immune response. Herein, we examined the role of HIV-1 Nef in mediating the upregulation of checkpoint receptors on peripheral blood mononuclear cells. We demonstrate that the HIV-1 accessory protein Nef upregulates cell surface levels of the checkpoint receptor T-cell immunoglobulin mucin domain-3 (Tim-3) and that this is dependent on Nef's dileucine motif LL_164/165. Furthermore, we used a bimolecular fluorescence complementation assay to demonstrate that Nef and Tim-3 form a complex within cells that is abrogated upon mutation of the Nef dileucine motif. We also provide evidence that Nef moderately promotes Tim-3 shedding from the cell surface in a dileucine motif–dependent manner. Treating HIV-1-infected CD4⁺ T cells with a matrix metalloprotease inhibitor enhanced cell surface Tim-3 levels and reduced Tim-3 shedding. Finally, Tim-3-expressing CD4⁺ T cells displayed a higher propensity to release the proinflammatory cytokine interferon-gamma. Collectively, our findings uncover a novel mechanism by which HIV-1 directly increases the levels of a checkpoint receptor on the surface of infected CD4⁺ T cells.

Elevated soluble Tim-3 correlates with disease activity of systemic lupus erythematosus

T cell immunoglobulin and mucin domain-containing molecule-3(Tim-3) has been found to play important roles in systemic lupus erythematosus (SLE), but whether sTim-3 is involved in the development of SLE remains unknown. In this study, we firstly observed an increased expression of plasma sTim-3 in SLE patients, especially active SLE patients. The plasma sTim-3 levels were positively correlated with anti-dsDNA, SLEDAI score, ESR, and urine albumin. The plasma sTim-3 levels were negatively correlated with C3 and C4. The area under the ROC curve (AUC) values indicated that the plasma sTim-3 level was significantly discriminative of early active SLE from stable SLE and HC with high sensitivity and specificity. The present results suggest that sTim-3 might serve as a potential biomarker for promising the disease activity of SLE.

TIM-3 pathway dysregulation and targeting in cancer

INTRODUCTION

Dysfunction of the immune system is a hallmark of cancer. Through increased understanding of the complex interactions between immunity and cancer, immunotherapy has emerged as a treatment modality for different types of cancer. Promising activity with immunotherapy has been reported in numerous malignancies, but challenges such as limited response rates and treatment resistance remain. Furthermore, outcomes with this therapeutic approach in hematologic malignancies are even more limited than in solid tumors. T-cell immunoglobulin domain and mucin domain 3 (TIM-3) has emerged as a potential immune checkpoint target in both solid tumors and hematologic malignancies. TIM-3 has been shown to promote immune tolerance, and overexpression of TIM-3 is associated with more aggressive or advanced disease and poor prognosis.

AREAS COVERED

This review examines what is currently known regarding the biology of TIM-3 and clinical implications of targeting TIM-3 in cancer. Particular focus is given to myeloid malignancies.

EXPERT OPINION

The targeting of TIM-3 is a promising therapeutic approach in cancers, including hematologic cancers such as myeloid malignancies which have not benefited much from current immunotherapeutic treatment approaches. We anticipate that with further clinical evaluation, TIM-3 blockade will emerge as an important treatment strategy in myeloid malignancies.

Association of soluble T cell immunoglobulin domain and mucin-3 (sTIM-3) and mac-2 binding protein glycosylation isomer (M2BPGi) in patients with autoimmune hepatitis

Background

Autoimmune hepatitis (AIH) is a disorder of unknown etiology in which immune-mediated liver injury progress to cirrhosis or hepatocellular carcinoma (HCC). The aim of the present study was to determine whether circulating soluble TIM3 (sTIM3) is elevated in patients with AIH patients and whether sTIM-3 levels are associated with clinical parameters of AIH.

Methods

We enrolled 123 Japanese patients with AIH who were identified from the National Hospital Organization–AIH-liver–network database, as well as 32 patients with chronic hepatitis C (CHC), 30 patients with primary biliary cholangitis (PBC) and healthy control subjects. Serum sTIM-3 concentrations were quantified by ELISA.

Results

Serum levels of sTIM-3 were significantly higher in AIH patients (median 4865 pg/ml; [interquartile range (IQR); 3122–7471]) compared to those in CHC (1026 pg/ml [IQR: 806–1283] p<0.001), PBC (2395 pg/ml [IQR: 2012–3422] p<0.001) or healthy controls (1285 pg/ml [IQR: 1098–1812] p<0.001). In AIH group, serum sTIM-3 were correlated with alanine aminotransferase (ALT), or total bilirubin (TB) and negatively correlated with serum levels of albumin (Alb). Serum levels of sTIM-3 were also strongly correlated with Mac-2 binding protein glycosylation isomer (M2BPGi) levels, but did not correlate with the histological grade of liver fibrosis. Steroid treatment of AIH patients significantly reduced serum sTIM-3 levels (2147±623pg/ml versus 1321±378pg/ml, p<0.001).

Conclusions

Circulating sTIM-3 levels were elevated in AIH patients and are associated with AIH disease activity and AIH-related liver damage. These findings indicate that serum sTIM-3 correlated with disease status of AIH and could be useful biomarkers to detect autoimmune-mediated liver injury. Our data suggest a possible link between the TIM-3/GAL-9 pathway and AIH severity or phenotype, and further investigations of the TIM-3 pathway and AIH pathophysiology is warranted.

Targeting novel inhibitory receptors in cancer immunotherapy

T cells play a critical role in promoting tumor regression in both experimental models and humans. Yet, T cells that are chronically exposed to tumor antigen during cancer progression can become dysfunctional/exhausted and fail to induce tumor destruction. Such tumor-induced T cell dysfunction may occur via multiple mechanisms. In particular, immune checkpoint inhibitory receptors that are upregulated by tumor-infiltrating lymphocytes in many cancers limit T cell survival and function. Overcoming this inhibitory receptor-mediated T cell dysfunction has been a central focus of recent developments in cancer immunotherapy. Immunotherapies targeting inhibitory receptor pathways such as programmed cell death 1 (PD-1)/programmed death ligand 1 and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), alone or in combination, confer significant clinical benefits in multiple tumor types. However, many patients with cancer do not respond to immune checkpoint blockade, and dual PD-1/CTLA-4 blockade may cause serious adverse events, which limits its indications. Targeting novel non-redundant inhibitory receptor pathways contributing to tumor-induced T cell dysfunction in the tumor microenvironment may prove efficacious and non-toxic. This review presents preclinical and clinical findings supporting the roles of two key pathways-T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) and T cell immunoreceptor with Ig and ITIM domain (TIGIT)/CD226/CD96/CD112R-in cancer immunotherapy.

Tim-3 Promotes Listeria monocytogenes Immune Evasion by Suppressing Major Histocompatibility Complex Class I

BACKGROUND

T-cell immunoglobulin and mucin protein 3 (Tim-3) is an immune checkpoint inhibitor that has therapeutic implications for many tumors and infectious diseases. However, the mechanisms by which Tim-3 promotes immune evasion remain unclear.

METHODS

In this study, we demonstrated that Tim-3 inhibits the expression of major histocompatibility complex class I (MHC-I) in macrophages at both the messenger ribonucleic acid and protein levels by inhibiting the STAT1-NLRC5 signaling pathway.

RESULTS

As a result, MHC-I-restricted antigen presentation by macrophages was inhibited by Tim-3 both in vitro and in a Listeria monocytogenes infection model in vivo. Systemic overexpression of Tim-3 or specific knockout of Tim-3 in macrophages significantly attenuated or enhanced CD8+ T-cell activation and infection damage in L monocytogenes-infected mice, respectively.

CONCLUSIONS

Thus, we identified a new mechanism by which Tim-3 promotes L monocytogenes immune evasion. Further studies on this pathway might shed new light on the physio-pathological roles of Tim-3 and suggest new approaches for intervention.

Serum Levels of T Cell Immunoglobulin and Mucin-Domain Containing Molecule 3 in Patients with Systemic Lupus Erythematosus

Objective: T cell immunoglobulin and mucin-domain-containing molecule 3 (TIM-3) is implicated in the development of various autoimmune diseases. We aimed to investigate the levels of soluble TIM-3 (sTIM-3) and their associations between clinical parameters in patients with systemic lupus erythematosus (SLE). Methods: Serum samples were collected from 65 patients with SLE and 35 age-matched healthy controls (HCs). The SLE Disease Activity Index 2000 (SLEDAI-2K) and the Systemic Lupus International Collaborating Clinics (SLICC) damage index (SDI) were used to assess SLE disease activity and SLE-related organ damage. British Isles Lupus Assessment Group (BILAG)-2004 index was also used to assess SLE disease activity. Soluble TIM-3 (sTIM-3) in sera from patients with SLE and HCs were evaluated by enzyme-linked immunosorbent assay (ELISA). The results were compared with the clinical parameters of SLE including SLE disease activity. Results: Serum sTIM-3 levels in patients with SLE (median 2123 pg/mL (interquartile range (IQR), 229–7235)) were significantly higher than those in HCs (1363 pg/mL; IQR, 1097–1673; p = 0.0015). Serum levels of sTIM-3 were correlated with disease activity of SLE using the SLEDAI-2K score (p < 0.001, r = 0.53). The serum sTIM-3 levels in SLE patients with active renal disease (BILAG renal index A-B) were significantly higher than those without the active renal disease (BILAG renal index C–E). However, no significant difference was observed in serum sTIM-3 levels between SLE patients with and without active involvement in other organs (BILAG index). Serum sTIM-3 levels were significantly elevated in SLE patients with organ damage (2710 pg/mL; IQR, 256–7235) compared to those without organ damage (1532 pg/mL; IQR, 228–5274), as assessed by the SDI (p = 0.0102). Conclusions: Circulating sTIM-3 levels are elevated in SLE patients, and serum sTIM-3 levels are associated with SLE disease activity and SLE-related organ damage. The data indicate a possible link between the TIM-3/Gal-9 pathway and SLE clinical phenotypes, and further investigation of the TIM-3 pathway in SLE pathophysiology is warranted.

sTim-3 alleviates liver injury via regulation of the immunity microenvironment and autophagy

Liver failure (LF) is a monocyte/macrophage-mediated liver injury that has been associated with inflammatory mediators. However, the mechanism through which monocytes/macrophages regulate LF has not been fully elucidated. In this study, we investigated the role of soluble T-cell immunoglobulin domain and mucin domain-containing molecule-3 (sTim-3) in inhibition of release of inflammatory mediators. We further assess this role in protection against D-galactosamine (D-GalN)/lipopolysaccharide (LPS)-induced acute liver failure (ALF), via monocyte/macrophage regulation and autophagy induction in mice. Our findings indicate significantly higher plasma sTim-3 in acute-on-chronic liver failure (ACLF) group relative to other groups, with this trend associated with disease progression. Furthermore, infiltrated recombinant sTim-3 inhibited release of various inflammatory mediators, including cytokines and human high-mobility group box-1 (HMGB1), potentially via autophagy induction. Furthermore, H&E staining and the low levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in ALF mice, supported that recombinant sTim-3 effectively alleviated liver injury. Moreover, sTim-3 induced changes in monocyte/macrophage population in mice's liver or blood, which consequently caused a reduction in proinflammatory CD11bhiF4/80lo monocyte-derived macrophages and Ly-6C(+)CD11b(+) monocytes. Conversely, sTim-3 increased autophagy levels of hepatic CD11b(+) monocyte-derived macrophages and decreased apoptosis rate of CD11b (+) monocytes in the blood. Collectively, our findings demonstrated that sTim-3 alleviated inflammatory response and liver injury by promoting autophagy and regulating monocyte/macrophage function. This indicates its potential for future development of novel therapeutic strategies against LF.

Tumor-associated neutrophils suppress antitumor immunity of NK cells through the PD-L1/PD-1 axis

Studies have begun to emerge showing the protumor effects of tumor-associated neutrophils (TANs) in tumorigenesis, which may involve dysfunction of NK cells. However, the mechanism through which these rebellious neutrophils modulate NK cell immunity in tumor-bearing state remains unclear. In the present study, we demonstrate that neutrophils can impair the cytotoxicity and infiltration capability of NK cells, and downregulate CCR1 resulting in the weakened infiltration capability of NK cells. Moreover, neutrophils can decrease the responsiveness of NK-activating receptors, NKp46 and NKG2D. Mechanistically, enhanced PD-L1 on neutrophils and PD-1 on NK cells, and subsequent PD-L1/PD-1 interactions were the main mechanisms determining the suppression of neutrophils in NK cell immunity. G-CSF/STAT3 pathway was responsible for PD-L1 upregulation on neutrophils, while IL-18 was essential for PD-1 enhancement on NK cells. The crosstalk between neutrophils and NK cells was cell-cell interaction-dependent. These findings suggest that neutrophils can suppress the antitumor immunity of NK cells in tumor-bearing status through the PD-L1/PD-1 axis, highlighting the importance of PD-L1/PD-1 in the inhibitory effect of neutrophils on NK cells. Targeting G-CSF/STAT3 and IL-18 signaling pathway may be potential strategies to inhibit residual tumor in tumor therapy.

Hepatocytes paradoxically affect intrahepatic IFN-γ production in autoimmune hepatitis due to Gal-9 expression and TLR2/4 ligand release

Hepatocytes are the targets in autoimmune hepatitis (AIH) that results in T cell-dependent liver injury. However, hepatocytes may also affect the hepatic T cells in AIH, but the underlying mechanisms are not fully understood. Here we report that hepatocytes could secrete galectin-9 (Gal-9) to suppress the intrahepatic production of Th1 cytokine IFN-γ and restrict AIH development, but hepatocyte damage resulted in opposite effects due to release of TLR2/4 ligands that promoted the intrahepatic production of IL-1β, IL-6, and IL-12. Through Tim-3, Gal-9 could efficiently suppress the intrahepatic T cell activation despite presence of TLR2/4 ligands, thus attenuating Th1 response in AIH. Intriguingly, intrahepatic IL-6/IL-12 suppressed the effect of TGF-β on Treg cells. Therefore, in AIH, Gal-9 promoted Foxp3 expression and function of hepatic Treg cells through TL1A signaling, although Treg function was still impaired, compared with that in naive state. Due to its promoting effect on Treg function, together with its effect on T effector cells in a Tim-3-independent way, Gal-9 could attenuate intrahepatic IFN-γ production by hindering the increase of hepatic CD4⁺CD43⁺ T cells resulting from extrahepatic T cell activation. TLR2/4 ligands attenuated the effects of Gal-9 on Treg cells and CD4⁺CD43⁺ T cells by increasing intrahepatic IL-6 and IL-12. Blocking TLR2/4 ligands could efficiently suppress intrahepatic IFN-γ production, liver injury, and hepatic fibrosis. These findings suggest that hepatocytes paradoxically affect Th1 response in AIH due to Gal-9 expression and TLR2/4 ligands release, and that targeting TLR2/4 signaling may provide an important approach in the therapeutic strategy for AIH.

Tim-3: A co-receptor with diverse roles in T cell exhaustion and tolerance

T cell inhibitory co-receptors play a crucial role in maintaining the balance between physiologic immune responses and maladaptive ones. T cell immunoglobulin and mucin domain-containing-3 (Tim-3) is a unique inhibitory co-receptor in that its expression is chiefly restricted to interferon (IFN)γ-producing CD4⁺ and CD8⁺ T cells. Early reports firmly established its importance in maintaining peripheral tolerance in transplantation and autoimmunity. However, it has become increasingly clear that Tim-3 expression on T cells, together with other check-point molecules, in chronic infections and cancers can hinder productive immune responses. In this review, we outline what is currently known about the regulation of Tim-3 expression, its ligands and signaling. We discuss both its salutary and deleterious function in immune disorders, as well as the T cell-extrinsic and -intrinsic factors that regulate its function.

Soluble Tim3 detection by time-resolved fluorescence immunoassay and its application in membranous nephropathy

Background

We aimed to develop a time‐resolved fluorescence immunoassay (TRFIA) for detecting soluble T‐cell immunoglobulin and mucin domain 3 (sTim3) in serum samples and to demonstrate a preliminary application of this method in membranous nephropathy (MN).

Methods

sTim3 TRFIA was developed, and the sTim3 concentration in the serum of patients with MN and healthy individuals was detected using a sandwich method.

Results

The sensitivity of the developed sTim3 TRFIA was 0.66 ng/mL, higher than that of an enzyme‐linked immunosorbent assay (ELISA) (1.11 ng/mL). The detection range was 0.66‐40 ng/mL. The intra‐assay coefficient of variation (CV) for sTim3 was 1.64%‐4.68%, and the inter‐assay CV was 5.72%‐9.32%. The cross‐reactivity to interleukin 6 (IL‐6) and kidney injury molecule 1 (KIM‐1) was 0.25% and 0.04%, respectively. The average recovery was 105.26%. The sTim3 concentration in patients with MN was considerably higher than that in healthy individuals (P < .001). The sTim3 concentration in the serum of patients with MN was significantly increased from G1 to G4 based on the Jonckheere‐Terpstra test (P < .001). Thus, we used sTim3 as a diagnostic indicator for distinguishing between healthy individuals and patients with MN as well as between different stages of MN.

Conclusion

We successfully established TRFIA to detect sTim3 in serum. We then applied this method to patients with MN, demonstrating for the first time that TRFIA is a valid diagnostic tool to detect sTim3 in serum.

TIM-3: An emerging target in the liver diseases

T cell immunoglobulin domain and mucin domain-containing molecule 3 (TIM-3) is found expression in the surface of terminally differentiated T cells and belongs to the TIM family of type Ⅰ transmembrane proteins. It binds to the ligand Galectin-9 and mediates T cell apoptosis. As the research progresses, TIM-3 is also expressed in Th17, NK, monocyte, which binds to ligand and induce immune peripheral tolerance in both mice and man. Numerous researches have demonstrated that TIM-3 influences liver diseases, including liver-associated chronic viral infection, liver fibrosis, liver cancer et al and suggest new approaches to intervention. Currently, targeted therapy of TIM-3 is a new treatment in the field of immunization. Although many studies have proven that TIM-3 has an inhibitory effect in vivo, the specific mechanism is not clear. Herein, we summarize the important role of TIM-3 in the regulation of liver disease and prospects for future clinical research. TIM-3 will provide new targets for improving clinical liver disease.

Soluble T cell immunoglobulin mucin domain 3 (sTim-3) in maternal sera: a potential contributor to immune regulation during pregnancy

Objective: The immune checkpoint inhibitor, membrane-bound T cell immunoglobulin mucin domain 3 (Tim-3), binds to galectin-9 (gal-9) and promotes immune tolerance during pregnancy. Soluble Tim-3 (sTim-3) competes with Tim-3 for binding to gal-9 and modulates its activity. Our objective was to evaluate the influence of sTim-3 on immune responses and outcome in pregnant women.Study design: Peripheral blood from 71 pregnant women was separated into mononuclear cell (PBMC) and plasma fractions. The PBMCs were lysed and tested for Tim-3 by ELISA. Plasma was assayed for sTim-3, gal-9, tumor necrosis factor-α (TNF-α), interleukin-10 (IL-10) and the stress-inducible 70 kDa heat shock protein (hsp70) by enzyme-linked immunosorbent assay (ELISA). Correlations were analyzed by the Spearman rank correlation test.Results: The higher the sTim-3 level in plasma the lower was the PBMC Tim-3 concentration (p = .0135), suggesting that sTim-3 results from the release of membrane-bound Tim-3. Plasma sTim3 levels were positively correlated with levels of gal-9 (p < .0001), TNF-α (p = .0071) and hsp70 (p = .0144), but not with IL-10. The sTim-3 level was positively associated (p = .0276) with gestational age at delivery. There was no association between sTim-3 and gestational age at sample collection, maternal age, gravidity, parity or body mass index.Conclusion: The release of Tim-3 from membranes and sTim-3 reacting with gal-9 may increase proinflammatory immunity and the stress response. The release of sTim-3 from lymphoid cells into the circulation and its binding to gal-9 may modulate Tim-3-mediated activity and help optimize immune regulation during pregnancy.

Chemical induced inflammation of the liver breaks tolerance and results in autoimmune hepatitis in Balb/c mice

Autoimmune hepatitis (AIH) is a chronic liver disease mediated by immunity, and could lead to liver fibrosis and hepatocellular carcinoma. However, the mechanisms for breaking hepatic tolerance and driving AIH still remain elusive. We herein reported that the non-specific liver inflammation triggered by carbon tetrachloride (CCl₄) recruited high numbers of CD4+T, CD8+T and B cells, and elevated the expression of proinflammaitory cytokines in Balb/c mice, further breaking liver tolerance and inducing autoimmune response, AIH inflammation and liver fibrosis in the presence of CYP2D6 antigen mimicry. In contrast, adenovirus infection could not break liver tolerance and induce AIH in Balb/c mice even in the presence of CYP2D6 antigen mimicry. These results suggested that genetic predisposition could determine liver tolerance in Balb/c mice. The chemical induced inflammation in the liver breaks tolerance and might be considered important for the initiation and development of AIH in Balb/c mice.

Level of serum soluble Tim-3 expression in early-phase acute pancreatitis

BACKGROUND/AIMS

T-cell immunoglobulin and mucin domain 3 (Tim-3) assumedly play a crucial immunomodulatory role in inflammatory response. Data on the potential role of soluble Tim-3 (sTim-3) in acute pancreatitis (AP) are scarce. We conducted a prospective clinical study to characterize its role in the early-phase AP.

METHODS

In total, 44 patients with AP (16 mild and 28 none-mild) who presented within 24 hours on admission and 20 healthy volunteers (NC) were included in our study. Serum interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-α, and sTim-3 levels were detected using enzyme-linked immunosorbent assay (ELISA).

RESULTS

Levels of the pro-inflammatory cytokines IL-6 and TNF-α and the anti-inflammatory cytokine IL-10 in the none-mild and mild groups were significantly elevated compared with those of the NC group. The sTim-3 levels of the none-mild and mild group were significantly increased compared with the NC. The sTim-3 level positively correlated with the IL-6 and TNF-α but showed no obvious correlations with the IL-10 level. The sTim-3 level positively correlated with the APACHE II score.

CONCLUSION

The results indicate that sTim-3 participates in the early progression of AP by positively regulating the pro-inflammatory cytokines and that the measurement of serum sTim-3 is an early marker for predicting AP.

Effect of soluble cleavage products of important receptors/ligands on efferocytosis: Their role in inflammatory, autoimmune and cardiovascular disease

Efferocytosis, the clearance of apoptotic cells (ACs), is a physiologic, multifaceted and dynamic process and a fundamental mechanism for the preservation of tissue homeostasis by avoiding unwanted inflammation and autoimmune responses through special phagocytic receptors. Defective efferocytosis is associated with several disease states, including cardiovascular disease and impaired immune surveillance, as occurs in cancer and autoimmune disease. A major cause of defective efferocytosis is non-functionality of surface receptors on either the phagocytic cells or the ACs, such as TAM family tyrosine kinase, which turns to a soluble form by cleavage/shedding or alternative splicing. Recently, soluble forms have featured prominently as potential biomarkers, indicative of prognosis and enabling targeted therapy using several commonly employed drugs and inhibitors, such as bleomycin, dexamethasone, statins and some matrix metalloproteinase inhibitors such as TAPI-1 and BB3103. Importantly, to design drug carriers with enhanced circulatory durability, the adaptation of soluble forms of physiological receptors/ligands has been purported. Research has shown that soluble forms are more effective than antibody forms in enabling targeted treatment of certain conditions, such as autoimmune diseases. In this review, we sought to summarize the current knowledge of these soluble products, how they are generated, their interactions, roles, and their potential use as biomarkers in prognosis and treatment related to inflammatory, cardiovascular, and autoimmune diseases.

Biochemical mechanisms implemented by human acute myeloid leukemia cells to suppress host immune surveillance

Acute myeloid leukaemia (AML) is a blood/bone marrow cancer originating from myeloid cell precusors capable of self-renewing. AML cells implement biochemical mechanisms which allow them not only to survive, but also to successfully escape immune surveillance. ln this work, we discuss crucial molecular mechanisms used by human AML cells in order to evade immune attack.

TLR2/4 ligand-amplified liver inflammation promotes initiation of autoimmune hepatitis due to sustained IL-6/IL-12/IL-4/IL-25 expression

Autoimmune hepatitis (AIH), a serious autoimmune liver disease, can be a lifelong illness, leading to fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). So far the mechanisms for disease initiation are largely unknown. Here we report that the amplified non-AIH liver inflammation could promote the initiation of AIH due to the sustained increase of IL-6, IL-12, IL-4, and IL-25 in the liver. The liver injury resulting from virus (adenovirus) or chemicals (CCl₄) could induce an amplified (stronger/long-lasting) hepatic inflammation by releasing the ligands for TLR2/TLR4. The amplified inflammation resulted in the increase of multiple cytokines and chemokines in the liver. Among them, the sustained increase of IL-6/IL-12 resulted in the activation of STAT3 and STAT4 in hepatic CD4⁺CD25⁺ Treg cells, thus suppressing Foxp3 gene expression to reduce the suppressive function of Treg cells in the liver, but not those in the spleen. The increase of IL-12 and the impairment of Treg function promoted Th1 response in presence of self-mimicking antigen (human CYP2D6). Intriguingly, the amplified inflammation resulted in the increase of IL-4 and IL-25 in the liver. The moderate increase of IL-4 was sufficient for cooperating with IL-25 to initiate Th2 response, but inefficient in suppressing Th1 response, favoring the initiation of autoimmune response. Consequently, either adenovirus/CYP2D6 or CCl₄/CYP2D6 could induce the autoimmune response and AIH in the mice, leading to hepatic fibrosis. The findings in this study suggest that the amplified non-AIH inflammation in the liver could be a driving force for the initiation of autoimmune response and AIH.