T-cell Immunoglobulin Mucin Research Articles

Abstract PR03: Combinatorial blockade of PD-1, CTLA-4, and LAG-3 pathways inhibits murine ovarian tumor growth.

Abstract We have previously shown that tumor-associated or infiltrating T cells (TALs or TILs) often co-express immune inhibitory receptors lymphocyte activation gene-3 (LAG-3) and programmed cell death 1 (PD-1) in human and murine ovarian tumor microenvironment (TME). Dual antibody blockade or genetic knockout of LAG3 and PD1 significantly enhanced T effector function and delayed ovarian tumor growth. The relative contribution of other immune inhibitory receptors to immune suppression in the ovarian TME, and whether they co-regulate each other are currently unknown. To address this, we analyzed the expression of multiple immune checkpoint proteins and their cognate ligands in ovarian tumor-bearing wild-type (WT), LAG3KO and PD1KO mice. We found that PD-1, cytotoxic T lymphocyte antigen 4 (CTLA-4), LAG-3, T-cell immunoglobulin domain and mucin domain 3 (TIM-3) and CD160 were elevated in TILs from the WT mice. Interestingly, compared with TILs of WT mice, the levels of LAG-3, TIM-3, and CTLA-4 were further significantly elevated in TILs from the tumor-bearing PD1KO mice; while the levels of PD-1, CTLA-4, and CD160 were further increased in the tumor-bearing LAG3KO mice. These results suggest that PD-1 and LAG-3 regulate the expression of multiple inhibitory receptors in the ovarian TME. Furthermore, combinatorial blockade with anti-LAG3 and anti-CTLA4 antibodies in the tumor-bearing PD1KO mice resulted in 30% tumor-rejection as compared to 10% by anti-CTLA4 alone or only delayed tumor growth by anti-LAG3. These data provide a strong basis for rational clinical testing of combinatorial blockade of the PD-1, LAG-3 and CTLA-4 immune inhibitory pathways for ovarian cancer immunotherapy. This abstract is also presented as Poster A51. Citation Format: Ruea-Yea Huang, AJ McGray, Kunle Odunsi. Combinatorial blockade of PD-1, CTLA-4, and LAG-3 pathways inhibits murine ovarian tumor growth. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr PR03.

Characterization of age-associated exhausted CD8⁺ T cells defined by increased expression of Tim-3 and PD-1.

Aging is accompanied by altered T-cell responses that result in susceptibility to various diseases. Previous findings on the increased expression of inhibitory receptors, such as programmed cell death protein 1 (PD-1), in the T cells of aged mice emphasize the importance of investigations into the relationship between T-cell exhaustion and aging-associated immune dysfunction. In this study, we demonstrate that T-cell immunoglobulin mucin domain-3 (Tim-3), another exhaustion marker, is up-regulated on aged T cells, especially CD8(+) T cells. Tim-3-expressing cells also produced PD-1, but Tim-3(+) PD-1(+) CD8(+) T cells had a distinct phenotype that included the expression of CD44 and CD62L, from Tim-3(-) PD-1(+) cells. Tim-3(+) PD-1(+) CD8(+) T cells showed more evident properties associated with exhaustion than Tim-3(-) PD-1(+) CD8(+) T cells: an exhaustion-related marker expression profile, proliferative defects following homeostatic or TCR stimulation, and altered production of cytokines. Interestingly, these cells produced a high level of IL-10 and induced normal CD8(+) T cells to produce IL-10, which might contribute to immune dysregulation in aged mice. The generation of Tim-3-expressing CD8(+) T cells in aged mice seems to be mediated by encounters with antigens but not by specific infection, based on their high expression of CD49d and their unbiased TCR Vβ usage. In conclusion, we found that a CD8(+) T-cell population with age-associated exhaustion was distinguishable by its expression of Tim-3. These results provide clues for understanding the alterations that occur in T-cell populations with age and for improving dysfunctions related to the aging of the immune system.

T Cell Immunoglobulin Mucin-3 (TIM-3) Expression on Peripheral Blood Lymphocytes in Chronic Hepatitis Virus C Infection

Introduction: T cell Immunoglobulin Mucin-3 (TIM-3) TIM-3 acts as a negative regulator of (T helper-1)Th1/ (T Cytotoxic-1)Tc1 cell function by triggering cell death upon interaction with its ligand Galectin-9, a feature observed in chronic viral diseases. Objective: To demonstrate the level of expression of TIM-3 on Peripheral Blood Mononuclear cells (PBCs) in cases of chronic HCV as a number of emerging molecules and pathways have been implicated in mediating the Tcell exhaustion characteristic of chronic viral infection. Patients and Methods: This study included 90 subjects, divided up as follows: Group 1 (35 patients) included HCV antibody positive with normal liver functions (Compensated), Group 2 (35 patients) comprised HCV antibody positive patients with abnormal liver functions (decompensated), and controls (Group 3) involved 20 apparently healthy persons (HCV antibody negative persons). The following laboratory investigations were performed for all participants in the 3 groups: Complete Blood Count (CBC), Blood Chemistry (liver functions), Special investigations (Flowcytometric study, and PCR for HCV RNA). Results: Comparing the control, compensated and decompensated groups regarding lymphocytic counts, ratios of TIM-3 positive cells within CD4, CD8, CD14 and CD56 cells in the three groups. Ratio of CD4 cells was higher in the compensated and control groups, than in the decompensated group, with non-significant difference. CD8 cells were maximum in the decompensated groups and minimum in the compensated group, with a significant p value. CD14 cells were maximum in the compensated group, followed by decompensated and minimum in the control group, again with a significant difference. CD56 showed non-significant differences between the three groups. A steady increase in the percentage of TIM +ve CD4, CD8, CD14 and CD 56 cells, with maximum percentages among the decompensated liver disease group, and least percentage among the control group was seen. The differences were significant regarding CD8 and CD56 and highly significant regarding CD4 and CD14 cells. Conclusions: Accumulation of TIM-3+ T cells is associated with functional impairment, and consequently with development of persistent HCV. The present study provides a basis for improving current therapies by simultaneous blockade of multiple inhibitory pathways that could result in additive efficacy without excessive toxicity. These findings have implications for the development of novel immunotherapeutic approaches to this common viral infection.

Tim-3 facilitates osteosarcoma proliferation and metastasis through the NF-κB pathway and epithelial-mesenchymal transition.

The aim of this study was to investigate the expression of T-cell immunoglobulin mucin domain molecule-3 (Tim-3) in osteosarcoma tissues, and analyze its effect on cell proliferation and metastasis in an osteosarcoma cell line. Tim-3 mRNA and protein expression in osteosarcoma tissue was detected by reverse transcriptase-polymerase chain reaction and immunohistochemistry, respectively. Additionally, the cell viability, apoptosis rate, and invasive ability of the osteosarcoma cell line MG-63 were tested using the methyl thiazolyl tetrazolium assay, Annexin V-propidium iodide flow cytometry, and a Transwell assay, respectively, following Tim-3 interference using small interfering RNA (siRNA). We also analyzed the expression of Snail, E-cadherin, vimentin, and nuclear factor (NF)-kB in the cells by western blot. We observed that Tim-3 mRNA and protein was significantly overexpressed in osteosarcoma tissues, compared to the adjacent normal tissue (P < 0.01). Moreover, MG-63 cells transfected with the Tim-3 siRNA presented lower cell viability, a greater number of apoptotic cells, and decreased invasive ability (P < 0.01), compared to control cells. Additionally, we observed a decrease in Snail and vimentin expression, an increase in the E-cadherin level, and an increase in NF-kB p65 phosphorylation (P < 0.01) in Tim-3 siRNA-transfected MG-63 cells. Based on these results, we concluded that Tim-3 is highly expressed in osteosarcoma tissue. Moreover, we speculated that interfering in Tim-3 expression could significantly suppress osteosarcoma cell (MG-63) proliferation and metastasis via the NF-kB/Snail signaling pathway and epithelial-mesenchymal transition.

Development of a Stable Cell Line, Overexpressing Human T-cell Immunoglobulin Mucin 1.

Recent researches have demonstrated that human T-cell immunoglobulin mucin 1 (TIM-1) glycoprotein plays important roles in regulation of autoimmune and allergic diseases, as well as in tumor immunity and response to viral infections. Therefore, targeting TIM-1 could be a potential therapeutic approach against such diseases. In this study, we aimed to express TIM-1 protein on Human Embryonic kidney (HEK) 293T cell line in order to have an available source of the TIM-1 antigen. The cDNA was synthesized after RNA extraction from peripheral blood mononuclear cells (PBMC) and TIM-1 cDNA was amplified by PCR with specific primers. The PCR product was cloned in pcDNA™3.1/Hygro (+) and transformed in Escherichia coli TOP 10 F'. After cloning, authenticity of DNA sequence was checked and expressed in HEK 293T cells. Finally, expression of TIM-1 was analyzed by flow cytometry and real-time PCR. The result of DNA sequencing demonstrated correctness of TIM-1 DNA sequence. The flow cytometry results indicated that TIM-1 was expressed in about 90% of transfected HEK 293T cells. The real-time PCR analysis showed TIM-1 mRNA expression increased 195-fold in transfected cells compared with un-transfected cells. Findings of present study demonstrated the successful cloning and expression of TIM-1 on HEK 293T cells. These cells could be used as an immunogenic source for production of specific monoclonal antibodies, nanobodies and aptamers against human TIM-1.

IMPS-20COMBINATION THERAPY WITH ANTI-PD-1, ANTI-TIM-3, AND FOCAL RADIATION RESULTS IN REGRESSION OF MURINE GLIOMAS

INTRODUCTION: Checkpoint molecules like programmed death-1 (PD-1) and T cell immunoglobulin mucin-3 (TIM-3) act as negative regulators of the immune system and can be upregulated in the setting of glioblastoma multiforme (GBM). Combined PD-1 blockade and stereotactic radiosurgery (SRS) have been shown to improve antitumor immunity and produces long-term survivors in a murine glioma model.1 However, tumor infiltrating lymphocytes can express multiple checkpoints (including TIM-3), and expression of ≥2 checkpoints corresponds to a more exhausted T cell phenotype.2 It was therefore hypothesized that the addition of a second checkpoint-blocking antibody could achieve additive or synergistic antitumor effects. METHODS: C57BL/6 mice were implanted with mouse glioma cell line GL261 transfected with luciferase and randomized into 8 treatment arms: (1) control, (2) SRS, (3) anti-PD-1 antibody, (4) anti-TIM-3 antibody, (5) anti-PD-1 + SRS, (6) anti-TIM-3 + SRS, (7) anti-PD-1 + anti-TIM-3, and (8) anti-PD-1 + anti-TIM-3 + SRS. Overall survival was measured. Brain, cervical lymph nodes, and peripheral blood were harvested on day 21 to assess immune activation. RESULTS: Survival benefits were observed with combined anti-TIM-3 antibody + SRS compared to anti-TIM-3 antibody alone with a median survival (MS) of 69 vs. 25 days and overall survival (OS) of 50% vs. 0%, respectively (p < 0.001 by log-rank Mantel-Cox). Dual blockade with anti-TIM-3 + anti-PD-1 antibody also improved survival compared to TIM-3 blockade alone, (MS of 100 vs. 25 days, OS 60% vs. 0%, respectively, p < 0.05). Notably, OS in the triple therapy group (anti-PD-1 + anti-TIM-3 + SRS) was 100% by day 100 (p < 0.05), a significant improvement compared to all other treatment arms. Flow cytometry of organs harvested on day 21 showed that compared to the dual therapy groups, mice treated with triple therapy had increased tumor infiltration by interferon-gamma+ (IFNg) and tumor necrosis factor-alpha+ (TNFa)-producing CD4+ T cells, as well as IFNg+ CD8+ lymphocytes. CONCLUSIONS: Combining anti-TIM-3 with anti-PD-1 and radiation was synergistic and conferred a significant survival benefit.

TIM-4 promotes the growth of non-small-cell lung cancer in a RGD motif-dependent manner.

Background:T-cell immunoglobulin domain and mucin domain 4 (TIM-4) is exclusively expressed in antigen-presenting cells and involved in immune regulation. However, the role of TIM-4 expressed in tumour cells remains completely unknown.Methods:Immunohistochemistry staining was used to examine TIM-4 or Ki-67 expression in tumour tissues. Real-time PCR or RT-PCR was performed to detect TIM-4 mRNA expression. Lung cancer cell growth and proliferation were conducted by CCK-8 assay and EdU staining. Cell cycle progression was analysed by flow cytometry. The PCNA and cell cycle-related proteins were verified by western blot. Co-IP assay was used to identify the interaction of TIM-4 and integrin αvβ3. The efficacy of TIM-4 in vivo was evaluated using xenograft tumour model.Results:The expression of TIM-4 in non-small-cell lung cancer (NSCLC) tissues was significantly higher than that of the adjacent tissues. Enhanced TIM-4 expression was negatively correlated with histological differentiation of lung carcinoma and lifespan of patients. Overexpression of TIM-4 promoted lung cancer cell growth and proliferation, and upregulated the expression of PCNA, cyclin A, cyclin B1 and cyclin D1, accompanied by accumulation of lung cancer cells in S phase. Interestingly, Arg-Gly-Asp (RGD) motif mutation abolished the effect of TIM-4 on lung cancer cells, which was further verified by tumour xenografts in mice. Furthermore, we found that TIM-4 interacted with αvβ3 integrin through RGD motif.Conclusions:This finding suggests that TIM-4 might be a potential biomarker for NSCLC that promotes lung cancer progression by RGD motif.

Ovarian carcinoma-infiltrating regulatory T cells were more potent suppressors of CD8(+) T cell inflammation than their peripheral counterparts, a function dependent on TIM3 expression.

Ovarian carcinoma is one of the most severe cancers in women, with a high relapse rate and limited secondary treatment options. To assist research in novel treatment technologies, including CD8(+) T cell-base immunotherapy, we examined the effect of tumor-infiltrating regulatory T cells (Tregs) in inhibiting CD8(+) T cell inflammation. We found that compared to their peripheral blood counterparts, tumor-infiltrating Tregs exhibited more potent inhibitory function, which was associated with higher interleukin 10 (IL-10) production in tumor-infiltrating Tregs. Blockade of T cell immunoglobulin mucin 3 (TIM3), a regulatory molecule overrepresented on tumor-infiltrating Tregs, had significantly reverted Treg-mediated suppression. Moreover, expression of TIM3 on tumor-infiltrating Tregs was directly correlated with tumor size. Together, our results demonstrated that ovarian tumor-infiltrating Treg cells were more immunosuppressive than their peripheral blood counterparts in a TIM3-dependent fashion.

Molecular characterization of T-cell immunoglobulin mucin domain-3 and Galectin-9 genes of swamp- and riverine-type water buffaloes.

Molecular characterization of T-cell immunoglobulin mucin domain-3 (TIM-3) and Galectin-9 (GAL-9) genes of swamp- and riverine-type water buffaloes was conducted to compare these genes with other species; determine the unique characteristic specific in water buffalo; and provide baseline information for the assessment of disease progression in buffalo species. TIM-3 and GAL-9 genes were amplified, purified, sequenced and characterized. The sequence result of TIM-3 in both types of water buffaloes contained 843 nucleotides encoding to 280 amino acids while GAL-9 of swamp-type and riverine-type water buffaloes contained 1023 and 972 nucleotides encoding to 340 and 323 amino acids, respectively. Meanwhile, the nucleotide and amino sequence of TIM-3 in water buffalo were 83-98% and 94-97% identical with other artiodactyl species, respectively. On the other hand, GAL-9 nucleotide and amino acid sequence in water buffalo were 85-98% and 76-96% identical with other artiodactyl species. The tyrosine-kinase phosphorylation motif and potential glycosylation sites were conserved within the tribe Bovinae. It is imperative to have further studies in the assessment of the role of these genes in disease progression in water buffalo during chronic infection. The study is the first report that describes the genetic characteristic of TIM-3 and GAL-9 genes in water buffalo.

Abstract A41: Galectin-9 has tumor promoting properties that may be targetable in metastatic melanoma

Abstract Introduction: Galectin-9 (Gal-9) is a carbohydrate-binding protein that interacts with T-cell immunoglobulin mucin 3 (TIM3) to modulate immune homeostasis. The Gal-9/TIM3 interaction down regulates activated T cells which promotes tumor growth, much like program death 1 (PD-1) and its ligand (PD-L1). Still, the effect Gal-9 has on the immune environment of melanoma patients is weakly understood. This study focuses on the role of Gal-9 in immunoregulation of healthy persons and metastatic melanoma patients. Methods: Soluble Gal-9 levels were determined from plasma collected from patients and healthy persons using standard ELISA methods. Proliferation and apoptosis of cells in the presence and absence of Gal-9 was determined by mixed lymphocyte reactions and Tunnel staining. Supernatants from these reactions were collected and run using a cytokine bead assay to determine changes in immune parameters with and without Gal-9. Results: Soluble Gal-9 was significantly higher in metastatic melanoma patients compared to healthy controls (3929 vs. 877 pg/mL, p=0.0003 respectively). In the presence of Gal-9, the proliferative effect of an allostimulus could be overridden until the level of responder cells to stimulator cells was 4:1. Using an apoptosis assay, Gal-9 was found to increase the level of cellular apoptosis; however, apoptosis was decreased as the allostimulus increased. Healthy cells incubated with Gal-9 were found to increase secretion of growth factors (EGF and FGF-2), chemokines (CXCL1, CXCL8, CCL2 and CCL3), T helper 1 cytokines (IFN-g and IL-7) which have shown tumor promoting affects and T helper 2 cytokines (IL-13 and IL-4). Conclusions: Gal-9 may potentially play a role in suppressing anti-tumor immunity. This suggests the use of a Gal-9 neutralizing antibody for therapeutic benefit in melanoma. Citation Format: Elizabeth Ann L. Enninga, Wendy K. Nevala, Svetomir N. Markovic. Galectin-9 has tumor promoting properties that may be targetable in metastatic melanoma. [abstract]. In: Proceedings of the AACR Special Conference: Tumor Immunology and Immunotherapy: A New Chapter; December 1-4, 2014; Orlando, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2015;3(10 Suppl):Abstract nr A41.

T cells Exhibit Reduced Signal Transducer and Activator of Transcription 5 Phosphorylation and Upregulated Coinhibitory Molecule Expression After Kidney Transplantation.

T-cell depletion therapy is associated with diminished interleukin (IL)-7/IL-15-dependent homeostatic proliferation resulting in incomplete T-cell repopulation. Furthermore, it is associated with impaired T-cell functions. We hypothesized that this is the result of impaired cytokine responsiveness of T cells, through affected signal transducer and activator of transcription (STAT)5 phosphorylation and upregulation of coinhibitory molecules. Patients were treated with T cell-depleting rabbit antithymocyte globulin (rATG) (6 mg/kg, n = 17) or nondepleting, anti-CD25 antibody (basiliximab, 2 × 40 mg, n = 25) induction therapy, in combination with tacrolimus, mycophenolate mofetil, and steroids. Before and the first year after transplantation, IL-7 and IL-2 induced STAT5 phosphorylation, and the expression of the coinhibitory molecules programmed cell death protein 1 (PD-1), T cell immunoglobulin mucin-3 (TIM-3), lymphocyte activation gene-3 (LAG-3), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), cluster of differentiation (CD) 160, and CD244 was measured by flow cytometry. The first year after rATG, CD4+, and CD8+ T cells were affected in their IL-7-dependent phosphorylation of STAT5 (pSTAT5) which was most outspoken in the CD8+ memory population. The capacity of CD4+ and CD8+ T cells to pSTAT5 in response to IL-2 decreased after both rATG and basiliximab therapy. After kidney transplantation, the percentage of TIM-3+, PD-1+, and CD160+CD4+ T cells and the percentage of CD160+ and CD244+CD8+ T cells increased, with no differences in expression between rATG- and basiliximab-treated patients. The decrease in pSTAT5 capacity CD8+ T cells and the increase in coinhibitory molecules were correlated. We show that memory T cells in kidney transplant patients, in particular after rATG treatment, have decreased cytokine responsiveness by impaired phosphorylation of STAT5 and have increased expression of coinhibitory molecules, processes which were correlated in CD8+ T cells.

TIM-3 and its ligand, galectin-9 constitute an autocrine loop to maintain stem cells in most human myeloid malignancies

Acute myeloid leukemia (AML) originates from self-renewing leukemic stem cells (LSCs), an ultimate therapeutic target for AML. We have reported that the T-cell immunoglobulin mucin-3 (TIM-3) is expressed on the surface of LSCs in most types of AML, and that TIM-3-targeted therapy could eradicate AML LSCs, based on in vivo xenograft experiments using patients’ AML samples (Kikushige et al., Cell Stem Cell, 2010). Since only the TIM-3+ but not the TIM-3- fraction of human AML cells can reconstitute human AML in immunodeficient mice, we hypothesized that the TIM-3 plays indispensable function to maintain AML LSCs.

PD-1(hi)TIM-3(+) T cells associate with and predict leukemia relapse in AML patients post allogeneic stem cell transplantation.

Prognosis of leukemia relapse post allogeneic stem cell transplantation (alloSCT) is poor and effective new treatments are urgently needed. T cells are pivotal in eradicating leukemia through a graft versus leukemia (GVL) effect and leukemia relapse is considered a failure of GVL. T-cell exhaustion is a state of T-cell dysfunction mediated by inhibitory molecules including programmed cell death protein 1 (PD-1) and T-cell immunoglobulin domain and mucin domain 3 (TIM-3). To evaluate whether T-cell exhaustion and inhibitory pathways are involved in leukemia relapse post alloSCT, we performed phenotypic and functional studies on T cells from peripheral blood of acute myeloid leukemia patients receiving alloSCT. Here we report that PD-1hiTIM-3+ cells are strongly associated with leukemia relapse post transplantation. Consistent with exhaustion, PD-1hiTIM-3+ T cells are functionally deficient manifested by reduced production of interleukin 2 (IL-2), tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ). In addition, these cells demonstrate a phenotype consistent with exhausted antigen-experienced T cells by losing TN and TEMRA subsets. Importantly, increase of PD-1hiTIM-3+ cells occurs before clinical diagnosis of leukemia relapse, suggesting their predictive value. Results of our study provide an early diagnostic approach and a therapeutic target for leukemia relapse post transplantation.

PD-1 and Tim-3 pathways are associated with regulatory CD8+ T-cell function in decidua and maintenance of normal pregnancy

CD8+ T cells are critical in the balance between fetal tolerance and antiviral immunity. T-cell immunoglobulin mucin-3 (Tim-3) and programmed cell death-1 (PD-1) are important negative immune regulatory molecules involved in viral persistence and tumor metastasis. Here, we demonstrate that Tim-3+PD-1+CD8+ T cells from decidua greatly outnumbered those from peripheral blood during human early pregnancy. Co-culture of trophoblasts with CD8+ T cells upregulated PD-1+ and/or Tim-3+ immune cells. Furthermore, the population of CD8+ T cells co-expressing PD-1 and Tim-3 was enriched within the intermediate memory subset in decidua. This population exhibited high proliferative activity and Th2-type cytokine producing capacity. Blockade of Tim-3 and PD-1 resulted in decreased in vitro proliferation and Th2-type cytokine production while increased trophoblast killing and IFN-γ producing capacities of CD8+ T cells. Pregnant CBA/J females challenged with Tim-3 and/or PD-1 blocking antibodies were more susceptible to fetal loss, which was associated with CD8+ T-cell dysfunction. Importantly, the number and function of Tim-3+PD-1+CD8+ T cells in decidua were significantly impaired in miscarriage. These findings underline the important roles of Tim-3 and PD-1 pathways in regulating decidual CD8+ T-cell function and maintaining normal pregnancy.

T-cell immunoglobulin domain and mucin domain 3 polymorphism affects cytokine expression in different cells and is associated with increased susceptibility to knee osteoarthritis

Osteoarthritis (OA) is a group of mechanical abnormalities involving degradation of joints, including articular cartilage and subchondral bone. In China, knee OA accounts for the majority of the OA cases. Elevated immune responses and proinflammatory cytokine expressions have been identified in OA patients. Tim-3 plays critical roles in down-regulating T cell responses. Here, we first examined the correlation between Tim-3 polymorphisms and the risk of knee OA. Data showed that the percentage of rs200181745TG (-1622G/T) genotype was significantly higher in knee OA patients compared to the controls (odds ratio [OR]=2.23, 95% confidence interval [CI]: 1.19–4.89, P<0.001). We further investigated the effects of the two Tim-3 polymorphisms on cytokine expressions in different cells. Results showed that subjects with rs200181745TG genotype presented increased mRNA and protein levels of interferon gamma (IFN-γ) from CD4+ T cells (P<0.001), and elevated mRNA level of IFN-γ from CD8+ T cells (P<0.001). However, the Tim-3 polymorphisms did not affect the expression of tumor necrosis factor alpha (TNF-α) in CD4+ and CD8+ T cells. These findings indicate that Tim-3 polymorphism can affect cytokine expression in different cells and is associated with increased susceptibility to knee OA.

Incomplete clearance of apoptotic cells in systemic lupus erythematosus: pathogenic role and potential biomarker.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with repeated inflammation against multiple organs. Although its pathophysiology is not yet unveiled, uncleared apoptotic cells and their accumulation in tissue contribute to the autoimmune disturbance in SLE. Apoptosis is a programmed cell death process, which maintains tissue homeostasis and inhibits the development of any further immune response against apoptotic remnants. Earlier studies revealed that various 'eat-me' signals on apoptotic cells, bridging molecules and their receptors on phagocytes play a role in such a complicated process. Tyro3-Axl-Mer receptors, their bridging molecules, milk fat globulin epidermal growth factor-8, T-cell immunoglobulin mucin domain protein family, scavenger receptors, C1q, and pentraxins were found to be abnormal in SLE. In this review, apoptosis and clearance of its remnants are summarized, and the molecules involved in the incomplete clearance of apoptotic cells in SLE are discussed.

Decreased Tim-3 expression is associated with functional abnormalities of monocytes in decompensated cirrhosis without overt bacterial infection

Patients with advanced cirrhosis usually exhibit altered monocyte function. However, the molecular mechanisms underlying the functional changes of monocytes are poorly understood. We investigated the role of T-cell immunoglobulin domain and mucin domain-containing molecule-3 (Tim-3) in regulating monocyte function in 94 patients with decompensated liver cirrhosis (DC-LC) (decompensation was defined by ascites, hepatic encephalopathy or upper gastrointestinal bleeding), 58 with compensated liver cirrhosis (C-LC) and 52 healthy controls (HC) by characterizing the frequency of Tim-3(+) monocytes, their phagocytosis capacity, HLA-DR expression, cytokine secretion and MAP kinase activation induced by lipopolysaccharide (LPS). Tim-3 expression on CD14(+) monocytes in DC-LC group were significantly lower than that in C-LC and HC and were associated with increased levels of plasma endotoxin, enhanced cytokine production, decreased phagocytic capacity, and reduced HLA-DR expression. Tim-3 expression on monocytes and monocyte function did not differ between C-LC and HC group. Tim-3(+)CD14(+) cells had more potent phagocytic capacity, higher levels of HLA-DR, CD86, CD80, CD163, and CD206 expression, but lower levels of CD1a and CD83, related to that of Tim-3(-)CD14(+) monocytes. In addition, Tim-3(+)CD14(+) cells produced less TNF-α but higher levels of IL-10 in response to LPS. Treatment with anti-Tim-3 antibody significantly reduced phagocytic capacity, but enhanced LPS-stimulated TNF-α, IL-6, and IL-10 secretion. Furthermore, blocking Tim-3 signaling increased p38 MAP kinase phosphorylation in monocytes upon LPS stimulation. Downregulation of Tim-3 expression was associated with endotoxemia and functional alterations of monocytes in patients with decompensated cirrhosis.

The Galectin-9/Tim-3 pathway is involved in the regulation of NK cell function at the maternal-fetal interface in early pregnancy.

Decidual natural killer (dNK) cells actively participate in the establishment and maintenance of maternal-fetal immune tolerance and act as local guardians against infection. However, how dNK cells maintain the immune balance between tolerance and anti-infection immune responses during pregnancy remains unknown. Here, we demonstrated that the inhibitory molecule T-cell immunoglobulin domain and mucin domain-containing molecule-3 (Tim-3) are expressed on over 60% of dNK cells. Tim-3(+) dNK cells display higher interleukin (IL)-4 and lower tumor necrosis factor (TNF)-α and perforin production. Human trophoblast cells can induce the transformation of peripheral NK cells into a dNK-like phenotype via the secretion of galectin-9 (Gal-9) and the interaction between Gal-9 and Tim-3. In addition, trophoblasts inhibit lipopolysaccharide (LPS)-induced pro-inflammatory cytokine and perforin production by dNK cells, which can be attenuated by Tim-3 neutralizing antibodies. Interestingly, a decreased percentage of Tim-3-expressing dNK cells were observed in human miscarriages and murine abortion-prone models. Moreover, T helper (Th)2-type cytokines were decreased and Th1-type cytokines were increased in Tim-3(+) but not Tim-3(-) dNK cells from human and mouse miscarriages. Therefore, our results suggest that the Gal-9/Tim-3 signal is important for the regulation of dNK cell function, which is beneficial for the maintenance of a normal pregnancy.

TIM-3 and Its Ligand, Galectin-9 Constitute a Pan-Myeloid Autocrine Loop to Develop and Maintain Malignant Stem Cells in Most Human Myeloid Leukemia

Acute myeloid leukemia (AML) originates from self-renewing leukemic stem cells (LSCs), an ultimate therapeutic target for AML. We have reported that the T-cell immunoglobulin mucin-3 (TIM-3) is expressed on the surface of LSCs in most types of AML, and that TIM-3-targeted therapy could eradicate AML LSCs, based on in vivo xenograft experiments using patients’ AML samples (Kikushige et al, Cell Stem Cell, 2010). Since only the TIM-3+ but not the TIM-3- fraction of human AML cells can reconstitute human AML in immunodeficient mice, we hypothesized that the TIM-3 plays indispensable function to maintain AML LSCs. Galectin-9 is a ligand for TIM-3, and ligation of TIM-3 by galectin-9 has been shown to phosphorylate tyrosine residues of TIM-3 and activate Src family kinases through its SH2 domain in T cells and monocytes.We found that serum galectin-9 concentration was significantly elevated in AML patients (431.1+58.6pg/ml, n=13) but not in the healthy individuals (25.2+6.8pg/ml, n=7) or patients with B cell malignancies (36.1+15.5pg/ml, n=10). Primitive CD34+ AML cells had abundant galectin-9 protein in their cytoplasms. We then transplanted human CD34+ primitive AML cells into irradiated immunodeficient mice. Strikingly, only in mice reconstituted with human AML, but not in those with normal cord blood or human ALL cells had elevated serum levels of human galectin-9: Serum galectin-9 levels were 234.7+69.0pg/ml (n=8) in mice reconstituted with primary human AML cells, whereas 4.64+4.64pg/ml (n=12) in mice with normal human hematopoiesis. These results collectively suggested that AML cells secreted galectin-9 in vivo in an autocrine manner. We then performed transcriptome analyses of primary CD34+TIM-3+ AML cells after galectin-9 ligation. Results were further evaluated by a pathway enrichment analysis, which demonstrated that both NF-κB and β-catenin pathways were activated. In fact, galectin-9 ligation of TIM-3+ human AML cells induced activation of the NF-κB pathway via ERK and AKT phosphorylation. Activation of ERK and AKT pathways are known to inhibit the GSK3β activity, and to promote the nucleus translocation of β-catenin in several cancers. To demonstrate significant nucleus translocation of β-catenin of primary AML cells, we established a quantitation system by utilizing the Array Scan VTI system. By this system, we could formally prove that TIM-3 ligation by galectin-9 significantly promoted the nucleus translocation of β-catenin in primary AML cells.We also have extensively analyzed TIM-3 and galectin-9 interaction in cells from patients with myeloid malignancies including myelodysplastic syndromes, myeloproliferative neoplasms and chronic myelogeneous leukemia. Strikingly, in all cases, frequencies of CD34+CD38-TIM-3+ cells dramatically increased along with disease progression from early/chronic phase to overt leukemias. Furthermore, serum levels of galectin-9 were also dramatically elevated after leukemic transformation. Significant nucleus translocation of β-catenin by galectin-9 ligation was also found in these diseases after leukemic transformation. A recent study has shown that NF-κB and β-catenin pathways could play a cooperative role in conferring the cancer-stem-cell properties to non stem cells in intestinal cancer model. These data collectively suggest that TIM-3 and galectin-9 constitutes a pan-myeloid autocrine loop to develop malignant stem cells in the vast majority of human myeloid malignancies. Thus, signaling molecules downstream of TIM-3 and galectin-9 ligation, as well as surface TIM-3 itself might be good candidates for cancer stem cell-target therapy common to most myeloid malignancies. DisclosuresNo relevant conflicts of interest to declare.

CEACAM1 regulates TIM-3-mediated tolerance and exhaustion.

T-cell immunoglobulin domain and mucin domain-3 (TIM-3, also known as HAVCR2) is an activation-induced inhibitory molecule involved in tolerance and shown to induce T-cell exhaustion in chronic viral infection and cancers. Under some conditions, TIM-3 expression has also been shown to be stimulatory. Considering that TIM-3, like cytotoxic T lymphocyte antigen 4 (CTLA-4) and programmed death 1 (PD-1), is being targeted for cancer immunotherapy, it is important to identify the circumstances under which TIM-3 can inhibit and activate T-cell responses. Here we show that TIM-3 is co-expressed and forms a heterodimer with carcinoembryonic antigen cell adhesion molecule 1 (CEACAM1), another well-known molecule expressed on activated T cells and involved in T-cell inhibition. Biochemical, biophysical and X-ray crystallography studies show that the membrane-distal immunoglobulin-variable (IgV)-like amino-terminal domain of each is crucial to these interactions. The presence of CEACAM1 endows TIM-3 with inhibitory function. CEACAM1 facilitates the maturation and cell surface expression of TIM-3 by forming a heterodimeric interaction in cis through the highly related membrane-distal N-terminal domains of each molecule. CEACAM1 and TIM-3 also bind in trans through their N-terminal domains. Both cis and trans interactions between CEACAM1 and TIM-3 determine the tolerance-inducing function of TIM-3. In a mouse adoptive transfer colitis model, CEACAM1-deficient T cells are hyper-inflammatory with reduced cell surface expression of TIM-3 and regulatory cytokines, and this is restored by T-cell-specific CEACAM1 expression. During chronic viral infection and in a tumour environment, CEACAM1 and TIM-3 mark exhausted T cells. Co-blockade of CEACAM1 and TIM-3 leads to enhancement of anti-tumour immune responses with improved elimination of tumours in mouse colorectal cancer models. Thus, CEACAM1 serves as a heterophilic ligand for TIM-3 that is required for its ability to mediate T-cell inhibition, and this interaction has a crucial role in regulating autoimmunity and anti-tumour immunity.