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T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) is a new immune checkpoint protein. Studies have shown that TIGIT can cause dysfunction of immune cells, weaken the anti-tumor effect, thus leading to tumor immune tolerance and immune escape. Blocking TIGIT can reverse immune cell failure and exert anti-tumor effect, which is expected to become a new therapeutic target for multiple myeloma.
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@#[摘 要] 目前，针对抑制性受体或配体、PD-1/PD-L1及CTLA-4的靶向免疫治疗已经取得了显著的临床成果，然而仍有许多患者未从免疫治疗中获益。因此，有必要寻找新的靶点及治疗方法，以提高免疫治疗的应答率。淋巴细胞上的T细胞免疫球蛋白及其ITIM结构域（T-cell immunoreceptor with immunoglobulin and ITIM domains，TIGIT）、CD226和CD112R等均属于免疫球蛋白超家族受体，与不同配体结合后传递抑制或激活信号，他们复杂的相互作用形成的整合信号能够调节免疫细胞的功能。对靶向TIGIT、CD226和CD112R的免疫治疗研究进展进行综述，包括TIGIT、CD226、CD112R的生物学特性，抑制肿瘤或促进肿瘤的机制，靶向治疗的研究进展。
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The imbalance of immune tolerance plays a key role in the pathogenesis of autoimmune hepatitis (AIH), and the abnormal expression of coinhibitory signal molecules for regulatory T cells (Treg) may be one of the important reasons for the destruction of autoantigen tolerance. As a coinhibitory signal molecule, T-cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) is an inhibitory receptor mainly expressed on Treg. This article elaborates on the immune mechanism of Treg associated with AIH and the role of TIGIT in the development, progression, and treatment of autoimmune diseases, so as to find the treatment strategy with TIGIT as the candidate target for AIH.
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T cell immunoglobulin and ITIM domain (TIGIT) is a novel immune checkpoint that has been considered as a target in cancer immunotherapy. Current available bioassays for measuring the biological activity of therapeutic antibodies targeting TIGIT are restricted to mechanistic investigations because donor primary T cells are highly variable. Here, we designed a reporter gene assay comprising two cell lines, namely, CHO-CD112-CD3 scFv, which stably expresses CD112 (PVRL2, nectin-2) and a membrane-bound anti-CD3 single-chain fragment variable (scFv) as the target cell, and Jurkat-NFAT-TIGIT, which stably expresses TIGIT as well as the nuclear factor of activated T-cells (NFAT) response element-controlled luciferase gene, as the effector cell. The anti-CD3 scFv situated on the target cells activates Jurkat-NFAT-TIGIT cells through binding and crosslinking CD3 molecules of the effector cell, whereas interactions between CD112 and TIGIT prevent activation. The presence of anti-TIGIT mAbs disrupts their interaction, which in turn reverses the inactivation and luciferase expression. Optimization and validation studies have demonstrated that this assay is superior in terms of specificity, accuracy, linearity, and precision. In summary, this reliable and effective reporter gene assay may potentially be utilized in lot release control, stability assays, screening, and development of novel TIGIT-targeted therapeutic antibodies.
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Objective:To explore the expression and clinical significance of immunosuppressive receptor T cell immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domain (TIGIT) on the peripheral blood mononuclear cells (PBMC) in silicosis patients with Mycobacterium tuberculosis infection. Methods:August 2018, a total of 78 patients with silicosis (all were quarry workers in Sanmen County, Zhejiang Province) were enrolled and divided into silicosis combined with active pulmonary tuberculosis group (APTB group), silicosis combined with latent tuberculosis infection group (LTBI group), and simple silicosis with non-tuberculosis infection group (non-TB group). Flow cytometry was used to analyze the expressions of TIGIT, programmed death-1 (PD-1) and transcription factor T-bet on PBMC from patients. Mann-Whitney U test and Pearson correlations analysis were used for statistical analysis. Results:Among the 78 patients, eight were in the APTB group, 24 in the LTBI group, and 46 in the non-TB group. The expressions of PD-1 and TIGIT on CD8 + T cells in the APTB group (29.45%(16.78%) and 65.40%(12.12%), respectively) were significantly higher than those in the LTBI group (17.40%(11.17%) and 48.30%(28.75%), respectively; U=23.500 and 43.500, respectively, P=0.000 8 and 0.020 5, respectively) and non-TB group (15.95%(12.46%) and 45.30%(19.75%), respectively; U=64.000 and 69.000, respectively, P=0.002 3 and 0.003 8, respectively), and the differences were all statistically significant. The expression of TIGIT was positively correlated with PD-1 on CD8 + T cells in silicosis patients ( r=0.434 3, P<0.01). The proportion of PD-1 + TIGIT + CD8 + T cells in the APTB group (19.90%(22.67%)) was significantly higher than those in the non-TB group (11.55%(11.29%), U=76.500, P=0.007 1) and LTBI group (11.55%(10.53%), U=41.000, P=0.015 4), while the proportion of PD-1 -TIGIT -CD8 + T cells in the APTB group (30.60%(12.90%)) was significantly lower than non-TB group (48.90%(18.98%), U=58.000, P=0.001 3) and LTBI group (47.20%(24.59%), U=41.000, P=0.015 4). The differences were all statistically significant. The expression of T-bet on the peripheral blood CD8 + T cells in the APTB group (29.45%(16.78%)) was higher than that in the non-TB group (15.95%(12.46%)) and the LTBI group (17.40%(11.17%)), and the differences were both statistically significant ( U=46.500 and 46.000, respectively, P=0.000 3 and 0.028 3, respectively). The expression of T-bet on CD8 + T cells was positively correlated with TIGIT on CD8 + T cells ( r=0.456 7, P<0.01). The expression of T-bet on PD-1 + TIGIT + CD8 + T cells in the APTB group (65.40%(12.12%)) was higher than those in the LTBI group (48.30%(28.75%), U=23.500, P=0.000 8) and non-TB group (45.30%(19.75%), U=65.000, P=0.002 6), and the differences were both statistically significant. Conclusion:The immunosuppressive receptor PD-1 and TIGIT are highly expressed on CD8 + T cells in silicosis patients with active pulmonary tuberculosis, which indicates CD8 + T cells exhaustion in these population, while the highly co-expression of T-bet suggests the exhausted subsets may have reversed potentiality.
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BACKGROUND: Previous studies have shown that stress response can cause immune dysfunction in the body. T cell immunoglobulin and ITIM domain (TIGIT) is an immunoregulatory receptor that can inhibit T cell activity, promote T cell apoptosis and promote T cell subgroup distribution imbalance. Whether the immune response mechanism of stress response is related to the expression and function of TIGIT is still unclear. OJECTIVE: To investigate the expression of immunomodulatory receptor TIGIT in thymus cells and peripheral blood mononuclear cells in an anger rat model and its significance to immune function. METHODS: Forty-eight Wistar male rats were randomly divided into normal group, 7-, 14-and 21-day model groups, with 12 rats in each group. In addition to the blank group, social isolation method with plantar electric shock method was used to establish rat anger models in the other groups. The behavioral changes of rats were observed by open-field test and aggressive behavior test, and the changes in body mass and thymus index before and after the test were recorded. The positive expression of TIGIT in thymus and peripheral blood mononuclear cells of rats in each group was observed by immunohistochemistry, and the expression levels of CD4+ and CD8+ T cells in the peripheral blood were measured by flow cytometry. The correlation between TIGIT expression in thymus and peripheral blood mononuclear cells and the CD4+/CD8+ ratio of T cell subsets in the peripheral blood was analyzed. An ethical approval for the study was obtained from the Animal Ethics Committee of Jiangxi University of Traditional Chinese Medicine. RESULTS AND CONCLUSION: In the 14-and 21-day model groups, the scores of horizontal and vertical activities in the open-field test of rats were higher than the control group (P < 0.05 or P < 0.01). In the 7-, 14-and 21-day model groups, the attack hiding time of the attack behavior test was significantly shortened (P < 0.01), the number of attacks and the cumulative attack time were significantly increased (P < 0.01), and the body mass and thymus index were significantly decreased compared with the control group (P < 0.05 or P < 0.01). In the 7-and 14-day model groups, the expression level of TIGIT in thymus and peripheral blood mononuclear cells was significantly higher than the control group (P < 0.01), while the CD4+/CD8+ ratio level of the peripheral blood T cell subsets was significantly lower than the control group (P < 0.05 or P < 0.01). The CD4+/CD8+ ratio of T cell subsets in the peripheral blood of random samples of rats was negatively correlated with the expression level of TIGIT in T cells of thymus (r2=0.627 0, P < 0.000 1) and in mononuclear cells (r2=0.624 4, P < 0.000 1). These results indicate that the model rats in the stress-induced anger state have obvious changes in animal behavior, present with thymus atrophy and abnormalities in peripheral blood T lymphocyte subsets CD4+/CD8+ ratio and immune function. This phenomenon may be related to the thymus and peripheral blood mononuclear cells TIGIT expression level, but the specific mechanism needs to be elucidated further.
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Objective To investigate the role of TIGIT signal in Th1/Th2 balance in the process of Schistosoma japonicum in-fection.Methods Male C57BL/6 mice were infected with cercariae of S.japonicum,and normal uninfected mice served as the controls.The percentages of TIGIT+cells,Ki67+CD3+CD4+TIGIT+cells,Ki67+CD3+CD4+TIGIT-cells,IFN-γ+CD3+CD4+TIGIT+cells,IFN-γ+CD3+CD4+TIGIT- cells,IL-4+CD3+CD4+TIGIT+cells and IL-4+CD3+CD4+TIGIT- cells were evaluated in mouse spleen by flow cytometry.Results The proportion of TIGIT+CD4+T cells was higher in the spleen of S.japonicum-infected mice than in the normal uninfected mice(29.30%±0.70% vs.3.09%±0.50%;t=8.834,P<0.01).However,no significant differ-ence in the percentages of TIGIT+CD8+T cells between the infection group and normal controls(3.61% ± 0.26% vs. 3.58% ± 0.16%;t=0.108,P>0.05),and no significant difference was detected in the percentages of TIGIT+cells in non-T cells be-tween the infection group and controls(1.86%±0.19% vs.1.37%±0.17%;t=1.931,P>0.05).In addition,the proportion of Ki67 in the TIGIT+cells was higher than that in the TIGIT-cells(17.03%±0.64% vs.6.59%±0.37%;t=14.09,P<0.01).The Th2/Th1 ratio was higher in the TIGIT+CD4+T cells than in the TIGIT-CD4+T cells(39.28%±3.75% vs.11.79%±1.64%;t=6.721,P<0.01).Conclusion The TIGIT signaling may be involved in the development of Th2 responses in the mice infected with S.japonicum.
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Immunotherapy is a therapeutic method that uses the immune system to inhibit tumor activity and kill tumor cells.It has been proved to be effective in the treatment of various malignant tumors.In general, the immune system can recognize and kill the abnormal cells,while the tumor cells can produce a variety of mechanisms to inhibit the immune system,resulting into the incomplete death of the cells.TIGIT is a type of inhibitory receptor containing T cell immunoglobulin and immunoreceptor protein tyrosine inhibitory motif (ITIM)protein domain.This paper discusses the role of TIGIT in limiting antitumor responses and reviews the mechanisms of action during the cancer immunity cycles.
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Objective To investigate the expression of T cell immunoreceptor with Ig and immunoreceptor tyrosine-based inhibitory domains (TIGIT) on peripheral CD4+ T and CD8+ T cells from patients with rheumatoid arthritis (RA) and its significance in order to clarify its role in the development of RA.Methods Peripheral blood samples were collected from 81 patients with RA and 33 healthy controls (HC).Expression of TIGIT on the surface of peripheral blood leukocytes was detected by flow cytometry.Differences in TIGIT expression between RA and HC groups were comparatively analyzed.Correlations of TIGIT expression on CD4+ T and CD8+ T cells with several laboratory indexes were analyzed.All data were statistically analyzed.Results (1) The percentage of TIGIT-expressing CD3+ T cells in patients with RA was significantly higher than that in HC (P<0.01).Moreover, the median fluorescence intensity (MFI) of TIGIT on CD3+ T cells was significantly elevated in patients with RA as compared with that in HC (P<0.01).No significant difference in the expression of TIGIT on B cells, monocytes or neutrophils was observed between RA and HC groups.(2) The percentages of TIGIT-expressing CD4+ T and CD8+ T cells were significantly elevated in patients with RA as compared with those in HC (P<0.01).Moreover, the MFI of TIGIT on CD4+ T and CD8+ T cells were significantly elevated in patients with RA as compared with those in HC (P<0.01).(3) The percentages of both TIGIT-expressing CD4+ T cells and TIGIT-expressing CD8+ T cells in patients with RA were positively correlated with erythrocyte sedimentation rate (ESR) (rs=0.355, P<0.01;rs=0.277, P=0.013).(4) The percentages of both TIGIT-expressing CD4+ T cells and TIGIT-expressing CD8+ T cells in patients with RA were positively correlated with rheumatoid factor (RF) (rs=0.265, P=0.017;rs=0.366, P<0.01).The MFI of TIGIT on CD4+ T cells was positively correlated with RF in RA group (rs=0.226, P=0.043).The percentage of TIGIT-expressing CD4+ T cells was positively correlated with anti-cyclic citrullinated peptide (anti-CCP) antibody in patients with RA who were positive for anti-CCP antibody (rs=0.324, P=0.012).(5) The percentage of TIGIT-expressing CD4+ T cells as well as the MFI of TIGIT on CD4+ T cells in patients with RA was positively correlated with Disease Activity Score-28 (DAS28) (r=0.232, P=0.038;r=0.343, P<0.010).Conclusion The expression of TIGIT on T cells is elevated in patients with RA and correlated with inflammatory markers, antibody production and disease activity.
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Objective · To prepare recombinant human TIGIT protein in E.coli and characterize its ability in binding Fusobacterium nucleatum (Fn). Methods · The gene of immunomodulatory protein of human TIGIT was amplified and cloned into pGEX4T2, and recombinant plasmid was transformed into E.coli BL21 (DE3) for GST-TIGIT fusion proteins were purified by the GST affinity chromatography and the interaction between GST-TIGIT fusion protein and Fn was tested by a pulldown assay. Results · Recombinant GST-TIGIT fusion protein expressed successfully in E.coli and was purified to homogeneity by GST affinity column. This protein could specifically bind to Fn, but not Lactobacillus acidophilus. Conclusion · High purify and activity of human GST-TIGIT fusion protein can be achieved by the prokaryotic expression system, and the adhesion between this protein and Fn has been preliminarily explored, which provides basis for further characterize interaction between them.
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Objective:To prepare the production of TIGIT-Fc fusion protein using H22 cells stably integrated the gene by lentivirus vector , and to explore the immunoregulatory effect on macrophages by TIGIT-Fc.Methods: TIGIT-Fc fusion gene were constructed by molecular cloning.The fusion gene was then subcloned to plasmids contained the secretion signaling peptide .The secrected TIGIT-Fc fusion gene was inserted into the lentivirus backbone vector.The purified lentivirus vector was the used to infect the murine H22 cell line.TIGIT-Fc protein was purified by protein A column from the ascites of H 22-injected C57BL/6 mice.Macrophages stimulated by lipopolysaccharide ( LPS ) was challenged to TIGIT-Fc treatment or control.Cytokine levels was then detected by ELISA.Results: TIGIT-Fc protein was purified from the ascites of H 22-injected mice.PVR was upregulated in LPS-treated macrophages.IL-10 level was upregulated in TIGIT-Fc treated macrophages.Conclusion: TIGIT-Fc promotes the mature macrophages to secrete anti-inflammatory cytokine IL-10.