Research Progress of Glioma Immunotherapy / 中山大学学报(医学科学版)

@#Gliomas are the most common primary malignant tumors in the central nervous system，and more than half of them are WHO grade IV glioblastomas. Even if surgery，concurrent chemoradiotherapy and adjuvant chemotherapy were applied，median survival of GBM patients is still only 14.2 months. Immunosuppression is an important feature of malignant glioma. Immunotherapy which reverse immunosuppression may be the most promising way to improve the treatment effect of glioma patients in recent years. This article reviews the recent progress of glioma immunotherapy and the research progress of regulatory T cells（Treg）and glucocorticoid-induced tumor necrosis factor receptor（GITR）in the glioma microenvironment. We hope this article will provides new research ideas for glioma immunotherapy.

In vivo fluctuation of Tax, Foxp3, CTLA-4, and GITR mRNA expression in CD4+CD25+ T cells of patients with human T-lymphotropic virus type 1-associated myelopathy

HTLV-1 Tax expression exerts an inhibitory effect on the Foxp3 transcription factor in CD4+CD25+ T-regulatory cells (Treg). For a better understanding of the role of Tax mRNA in the gene expression of cellular markers we measured Tax, Foxp3, CTLA-4, GITR, TGF-β, and IL-10 mRNA in Treg cells of 50 patients with human T-lymphotropic virus type 1 (HTLV-1)-associated myelopathy/tropical spastic paraparesis (HAM/TSP; 27 women and 23 men; mean age: 56.7 years). The control group consisted of 23 non-infected subjects (12 women and 11 men) with a mean age of 51.3 years. Real-time PCR was used to measure mRNA of Tax proteins and several cellular markers of Treg function. Determinations revealed a high level of Tax mRNA in HAM/TSP (124.35 copies/100 CD4+CD25+ T cells). Foxp3, GITR, and CTLA-4 mRNA levels were lower in HAM/TSP patients (mean ± SD, 22.07 ± 0.78, 9.63 ± 0.36, and 4.54 ± 0.39, respectively) than in non-infected controls (47.15 ± 12.94, 22.14 ± 1.91, and 21.07 ± 2.31). Both groups had similar levels of TGF-β and IL-10. An inverse relationship was found between Tax levels and Foxp3, CTLA-4, and GITR levels. Conversely, there was a direct correlation between levels of Foxp3, GITR, and CTLA-4. Disease severity and evolution time did not correlate with Tax or Foxp3 levels. The present results suggest that Tax and Foxp3 mRNA vary with the same degree of disease severity in HAM/TSP patients. Tax fluctuations may affect CTLA-4 and GITR expression via the Foxp3 pathway, causing virus-induced dysfunction of CD4+CD25+ T cells in HAM/TSP patients.

GITR expression on T-cell receptor-stimulated human CD8+ T cell in a JNK-dependent pathway.

Glucocorticoid-induced tumor necrosis factor receptor (TNFR) (GITR) family-related gene is a member of the TNFR super family. GITR works as one of the immunoregulatory molecule on CD4+ regulatory T cells and has an important role on cell survival or cell death in CD4+ T cells. Little is known about the expression of GITR on human CD8+ T cells on antigen-specific and non-specific activation. Here, we report that expression of GITR on human CD8+ T cells on T-cell receptor (TCR) (anti-CD3)-mediated stimulation is dependent on the JNK pathway. The activation of CD8+ T cells was measured by the expression of IL-2 receptor-α (CD25), GITR and by IFN-γ production upon re-stimulation with anti-CD3 antibody. We studied the signaling pathway of such inducible expression of GITR on CD8+ T cells. We found that a known JNK-specific inhibitor, SP600125, significantly down-regulates GITR expression on anti-CD3 antibody-mediated activated CD8+ T cells by limiting JNK phosphorylation. Subsequently, after stimulation of the CD8+ cells, we tested for the production of IFN-γ by the activated cells following restimulation with the same stimulus. It appears that the expression of GITR on activated human CD8+ T cells might also be regulated through the JNK pathway when the activation is through TCR stimulation. Therefore, GITR serves as an activation marker on activated CD8+ cells and interference with JNK phosphorylation, partially or completely, by varying the doses of SP600125 might have implications in CD8+ cytotoxic T cell response in translational research.

Regulatory T Cells and Their Molecular Markers in Peripheral Blood of the Patients with Systemic Lupus Erythematosus / 华中科技大学学报（医学）（英德文版）

Summary: CD4+CD25+ regulatory T cells (Tregs) and the expression of their molecular markers (GITR, Foxp3) in peripheral blood of the patients with systemic lupus erythematosus (SLE) were investigated in order to reveal the pathogenesis of SLE on the cellular and molecular levels. The level of Tregs in peripheral blood was detected by flow cytometry. The expression levels of GITR and Foxp3 mRNA in peripheral blood mononuclear cells (PBMCs) were assayed by reverse transcriptasepolymerase chain reaction (RT-PCR). The level of IL-6 in the plasma was measured by ELISA.Comparisons were made among 3 groups: the active SLE group, the inactive SLE group, and normal control group. The level of Tregs in the active SLE group and the inactive SLE group was significantly lower than in the normal control group (P<0.01). The level of Tregs in the active group was lower than in the inactive group with the difference being not significant (P>0.05). The level of Tregs in SLE patients was significantly negatively correlated with the disease active index in SLE (SLEDAI) (r=--0.81, P<0.01). The expression levels of GITR mRNA in PBMCs of the active SLE group and the inactive SLE group were significantly higher than in the normal control group (P<0.05), and those of Foxp3 mRNA in SLE patients of both active and inactive SLE groups were significantly lower than in the normal control group (P<0.05). There was no significant difference in the expression of GITR and Foxp3 mRNA between the active SLE group and inactive SLE group (P>0.05). The plasma levels of IL-6 in both the inactive SLE group and active SLE group were significantly higher than in the normal control group (P<0.01). The plasma level of IL-6 in the active S LE group was significantly increased as compared with that in the inactive SLE group (P<0.05), and the plasma level of IL-6 in SLE was significantly positively correlated with SLEDAI scores (r=0.58, P<0.01) and significantly negatively correlated with the ratio of CD4+CD25+ cells/CD4+ cells (r=-0.389, P<0.05). It was concluded that the levels of Tregs and Foxp3 mRNA in peripheral blood of SLE patients were decreased and the levels of GITR mRNA and plasma IL-6 were increased. The Tregs and their molecular markers GITR, Foxp3 as well as the plasma IL-6 might play an important role in the pathogenesis of SLE.

In vivo ligation of glucocorticoid-induced TNF receptor enhances the T-cell immunity to herpes simplex virus type 1

GITR (glucocorticoid-induced TNF receptor) is a recently identified member of the TNF receptor superfamily. The receptor is preferentially expressed on CD4+CD25+ regulatory T cells and GITR signals break the suppressive activity of the subset. In this study, we wanted to reveal the in vivo function of GITR in herpes simplex virus type 1 (HSV-1) infection. A single injection of anti-GITR mAb (DTA-1) immediately after viral infection significantly increased the number of CD4+ and CD8+ T cells expressing CD25, an activation surface marker, and secreting IFN-gamma. We confirmed these in vivo observations by showing ex vivo that re-stimulation of CD4+ or CD8+ T cells with a CD4+ or CD8+ T-cell-specific HSV-1 peptide, respectively, induced a significant elevation in cell proliferation and in IFN-gamma secretion. Our results indicate that GITR signals play a critical role in the T-cell immunity to HSV-1.

Anti-GITR antibody inhibits L615 leukemia in mouse / 第三军医大学学报

Objective To investigate the effect and the mechanism of the GITR-antibody(glucocorticoid-induced tumor necrosis factor receptor-ligand antibody) on the mouse leukemia model induced by L615.Methods The mouse leukemia models induced by L615 cells were divided into 4 groups: negative controls(peritoneal injection of normal saline,0.2 ml/d),GITR group(GITR,100,infused through caudal vein 2 d before leukemic lymphocytes inoculation,again at dose of 50 ?g/each mouse after inoculation),Cyclophosphamide group(200 mg?kg~(-1)?d~(-1),intraperitoneal injection from the 3~(rd) day after inoculation for 3 d),GITR+ Cyclophosphamide group(100 mg?kg~(-1)?d~(-1) Cyclophosphamide instead).The survival time,leukocyte counting in the peripheal blood,liver and spleen index were calculated and the pathological examination of liver,spleen were performed.Results GITR-ligand could prolong the survival time of mouse leukemia model,lead the necrosis and apoptosis of leukemic cells in bone marrow,decrease the liver and spleen index,decrease and relieve the leukocyte increase of peripheal blood and the irregular swelling of liver and spleen.Conclusion Through immunoregulation,GITR-antibody can inhibit the L615 leukemic cells effectively,therefore inhibit the progress of leukemia to some extent.

The expression of 4-1BB and GITR on CD4~+CD25~(high) T cells in peripheral blood of patients with multiple sclerosis / 中国免疫学杂志

0.05).Conclusion:The decrease in 4-1BB expression,rather than the GITR expression,on CD4+CD25high T cells of MS patients suggests that 4-1BB may be involved in the lower immunoactivity of the cell population,while the GITR may play a minor or fine role in the immunoregulation of the cells.