Induced Tumor Necrosis Factor Receptor Research Articles

Targeting immune checkpoints in anti-neutrophil cytoplasmic antibodies associated vasculitis: the potential therapeutic targets in the future.

Anti-neutrophil cytoplasmic autoantibodies (ANCA) associated vasculitis (AAV) is a necrotizing vasculitis mainly involving small blood vessels. It is demonstrated that T cells are important in the pathogenesis of AAV, including regulatory T cells (Treg) and helper T cells (Th), especially Th2, Th17, and follicular Th cells (Tfh). In addition, the exhaustion of T cells predicted the favorable prognosis of AAV. The immune checkpoints (ICs) consist of a group of co-stimulatory and co-inhibitory molecules expressed on the surface of T cells, which maintains a balance between the activation and exhaustion of T cells. CD28, inducible T-cell co-stimulator (ICOS), OX40, CD40L, glucocorticoid induced tumor necrosis factor receptor (GITR), and CD137 are the common co-stimulatory molecules, while the programmed cell death 1 (PD-1), cytotoxic T lymphocyte-associated molecule 4 (CTLA-4), T cell immunoglobulin (Ig) and mucin domain-containing protein 3 (TIM-3), B and T lymphocyte attenuator (BTLA), V-domain Ig suppressor of T cell activation (VISTA), T-cell Ig and ITIM domain (TIGIT), CD200, and lymphocyte activation gene 3 (LAG-3) belong to co-inhibitory molecules. If this balance was disrupted and the activation of T cells was increased, autoimmune diseases (AIDs) might be induced. Even in the treatment of malignant tumors, activation of T cells by immune checkpoint inhibitors (ICIs) may result in AIDs known as rheumatic immune-related adverse events (Rh-irAEs), suggesting the importance of ICs in AIDs. In this review, we summarized the features of AAV induced by immunotherapy using ICIs in patients with malignant tumors, and then reviewed the biological characteristics of different ICs. Our aim was to explore potential targets in ICs for future treatment of AAV.

Biodistribution and kinetic characters of radiopharmaceutical medication based on biospecific antibodies to tumor-associated stroma elements and 177lutcium

Biodistribution and kinetics were studied of potentially target biospecific radiopharmaceutical medication for the treatment of malignant tumors of various histologic type and location with expression of cytotoxic T-lymphocyte membrane associated glycoprotein 4 and glucocorticoid Induced Tumor Necrosis Factor Receptor) 177Lu-DOTA-anti-CTLA4-GITR. Colorectal cancer experimental model has been successfully reproduced by means of murine large intestine experimental adenocarcinoma cells (AKATOL) СТ26 EGFR) direct transplantation. The model was characteristic of moderate growth rate and practically complete absence of metastatic spread. Immunohistochemical assay of tumor tissue has revealed satisfactory expression level of target antigens for the medication under study, i.e. cytotoxic T-lymphocyte associated protein 4 (CTLA4) as well as membrane receptor of tumor necrosis factor group (GITR). This medication 177Lu-DOTA-anti-CTLA4-GITR has been shown to store in the tumor tissue. Its major pathways out of the organism were through urinary system. On the other hand, the medication has also been demonstrated to store in non-target tissues, namely: kidneys, liver, large intestine. The results of this study may be used in preclinical studies of medications and serve as a basis for broader studies of 177Lu-DOTA-anti-CTLA4-GITR and its safety.

MicroRNA‑30a controls the instability of inducible CD4+ Tregs through SOCS1.

Inducible regulatory T cells (iTregs) are an important subset of Tregs and play a role in the maintenance of peripheral tolerance, and the occurrence of a number of diseases, including tumors and autoimmune diseases. However, the instability of iTregs is a major obstacle for their potential application in clinical trials. The underlying mechanism of iTreg instability remains largely unknown. In the present study, the expression level of microRNA (miRNA/miR)‑30a in murine iTregs was evaluated using reverse transcription‑quantitative PCR. miR‑30a mimics and a miR‑negative control (NC) were transiently transfected into iTregs using Nucleofector technology. The effects of miR‑30a on the suppressive function of murine iTregs invitro and invivo were investigated using MTT, adoptive cell transfer (ACT) and flow cytometry assays, as well as a murine model of lung cancer. In the present study, it was identified that the expression level of miR‑30a was lower in murine iTregs invitro compared with natural (n)Tregs. Furthermore, compared with miR‑NC, miR‑30a mimics impaired the suppressive function of murine iTregs on murine CD4+ Tcell proliferation invitro, which was accompanied by the altered expression of cytotoxic Tlymphocyte‑associated antigen4 and glucocorticoid induced tumor necrosis factor receptor, as well as transforming growth factor‑β and interleukin‑10. It was also observed that, compared with miR‑NC, miR‑30a mimics abrogated the suppressive effects of murine iTregs on murine CD8+ Tcell function invivo, producing an effective antitumor effect in mice bearing 3LL lung cancer cells in the ACT assay. From a mechanistic point, the expression level of suppressor of cytokine signaling 1, a putative target of miR‑30a, was elevated, altering the activation of the Akt and STAT1 pathway in the miR‑30a mimic transfected group compared with the miR‑NC group, reducing the suppressive function of murine iTregs. The present study identified a role for miR‑30a in the instability of iTregs and provided a novel insight into the development of therapeutic strategies for promoting T‑cell immunity via the regulation of iTreg instability by targeting specific miRNAs.

Allergen-specific immunotherapy enhances CD8+ CD25+ CD137+ regulatory T cells and decreases nasal nitric oxide.

4-1BB (CD137), a member of the inducible tumor necrosis factor receptor (TNFR) family, is expressed on regulatory T (Treg) cells and regulates Treg cells to control allergic inflammation. Pam3CSK4, a synthetic TLR2 ligand that can expand CD8+ Treg function, is a promising adjuvant for allergen immunotherapy (IT). We examined whether Dermatophagoides pteronyssinus (Der p) IT and Pam3CSK4 could enhance CD8+ CD25+ CD137+ Treg suppressive function to decrease nasal nitric oxide (nNO) levels. Nasal symptom scores, nNO levels, PBMCs, and inferior turbinate biopsies were obtained from 40 mite-sensitive perennial allergic rhinitis (PAR) patients before and after one year of Der p IT and 30 non-allergic control subjects. CD137 expression on CD8+ CD25+ T cells and suppressive function of CD8+ CD25+ CD137+ Tregs was measured using flow cytometry. Cytokine levels were analyzed by ELISA. Inducible nitric oxide synthase production by nasal epithelial cells after co-culturing with CD8+ CD25+ CD137+ T cells was analyzed by Western blotting. Der p IT improved nasal symptom scores, decreased nNO levels, and increased CD137 expression on CD8+ T cells in PBMCs and nasal mucosa. Pam3CSK4 expanded the CD8+ CD25+ CD137+ population in PBMCs. Pam3CSK4-stimulated CD8+ CD25+ CD137+ Tregs induced IL-10 and TGF-β and suppressed CD4+ CD25- T-cell proliferation mainly by cell contact inhibition. CD8+ CD25+ CD137+ Tregs cultured with nasal epithelial cells suppressed Der p 2-induced iNOS production. Silencing CD137 in sorted CD8+ CD25+ T cells decreased Pam3CSK4-activated Foxp3 expression. Der p IT expanded CD8+ CD25+ CD137+ Tregs and decreased nNO levels. Induced CD137 expression on CD8+ CD25+ Tregs by Pam3CSK4 stimulation may help suppress allergic inflammation during IT.

Evolution of differential 4‐1BB signaling in Human and Murine immune system

4‐1BB (CD137) is an inducible tumor necrosis factor receptor superfamily (TNFRSF) member and is currently being targeted in cancer immunotherapy and autoimmunity. 4‐1BB interacts with its cognate ligand 4‐1BBL to promote T lymphocyte activation and proliferation, but the dissimilarities in mouse and human molecules might result in differential engagement of this pathway. To elucidate the molecular mechanism underlying this distinct behavior, we have determined the crystal structures of human and mouse 4‐1BB/4‐1BBL complexes. Collectively, these structures provide insights into the structural differences that drive the species‐specific receptor‐ligand interactions. The most significant feature is that the TNF homology domain of human (h)4‐1BBL form non‐covalent homo‐trimeric arrangements, whereas the mouse (m)4‐1BBL formed a novel disulfide linked homo‐dimer. In the human 4‐1BB/4‐1BBL complex, each receptor binds at the crevice formed between two protomers of h4‐1BBL resulting in the formation of a “hetero‐hexameric” functional signaling complex (1), whereas each m4‐1BB receptor binds exclusively to a single m4‐1BBL protomer leading to a “tetrameric” signaling unit (2). As multimerization and clustering is a prerequisite for TNFR intracellular signaling, appearance of differential functional signaling units in human and mouse supports a unique mechanism of 4‐1BB signaling in both of these species. Of note, we have discovered that h4‐1BB forms a disulfide‐linked dimer and this covalent receptor dimerization amplifies h4‐1BB signaling by cross‐linking individual ligand‐receptor complexes to form a 2D network. Since the m4‐1BBL dimer can only recruit two monomeric 4‐1BB receptors, cross‐linking of two hetero‐tetrameric signaling units via Galectin‐9 binding to the N‐linked glycans on m‐41BB is required for receptor oligomerization and strong signaling (3).While all characterized TNFR/TNF members exhibit interspecies cross reactivity between human and mouse molecules, 4‐1BB and 4‐1BBL lacks this distinguishing feature. Our structural studies together with comparison of human and mouse 4‐1BB/4‐1BBL complexes highlighted several differences between the ligand and receptor binding interfaces and provide an explanation for the absence of inter species cross‐reactivity between them (2). Furthermore, our biochemical and mutational analysis discloses more variations between mouse and human molecules that could affect signaling and thus suggest the generation of better animal models to study 4‐1BB biology in humans.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Crystal structures of the human 4-1BB receptor bound to its ligand 4-1BBL reveal covalent receptor dimerization as a potential signaling amplifier

Human (h)4-1BB (TNFRSF9 or CD137) is an inducible tumor necrosis factor receptor (TNFR) superfamily member that interacts with its cognate ligand h4-1BBL to promote T lymphocyte activation and proliferation. h4-1BB is currently being targeted with agonists in cancer immunotherapy. Here, we determined the crystal structures of unbound h4-1BBL and both WT h4-1BB and a dimerization-deficient h4-1BB mutant (C121S) in complex with h4-1BBL at resolutions between 2.7 and 3.2 Å. We observed that the structural arrangement of 4-1BBL, both unbound and in the complex, represents the canonical bell shape as seen in other similar TNF proteins and differs from the previously reported three-bladed propeller structure of 4-1BBL. We also found that the binding site for the receptor is at the crevice formed between two protomers of h4-1BBL, but that h4-1BB interacts predominantly with only one ligand protomer. Moreover, h4-1BBL lacked the conserved tyrosine residue in the DE loop that forms canonical interactions between other TNFR family molecules and their ligands, suggesting h4-1BBL engages h4-1BB through a distinct mechanism. Of note, we discovered that h4-1BB forms a disulfide-linked dimer because of the presence of an additional cysteine residue found in its cysteine-rich domain 4 (CRD4). As a result, h4-1BB dimerization, in addition to trimerization via h4-1BBL binding, could result in cross-linking of individual ligand-receptor complexes to form a 2D network that stimulates strong h4-1BB signaling. This work provides critical insights into the structural and functional properties of both h4-1BB and h4-1BBL and reveals that covalent receptor dimerization amplifies h4-1BB signaling.

Thiamine preserves mitochondrial function in a rat model of traumatic brain injury, preventing inactivation of the 2-oxoglutarate dehydrogenase complex

Background and purposeBased on the fact that traumatic brain injury is associated with mitochondrial dysfunction we aimed at localization of mitochondrial defect and attempted to correct it by thiamine. Experimental approachInterventional controlled experimental animal study was used. Adult male Sprague-Dawley rats were subjected to lateral fluid percussion traumatic brain injury. Thiamine was administered 1 h prior to trauma; cortex was extracted for analysis 4 h and 3 d after trauma. Key resultsIncreased expression of inducible nitric oxide synthase (iNOS) and tumor necrosis factor receptor 1 (TNF-R1) by 4 h was accompanied by a decrease in mitochondrial respiration with glutamate but neither with pyruvate nor succinate. Assays of TCA cycle flux-limiting 2-oxoglutarate dehydrogenase complex (OGDHC) and functionally linked enzymes (glutamate dehydrogenase, glutamine synthetase, pyruvate dehydrogenase, malate dehydrogenase and malic enzyme) indicated that only OGDHC activity was decreased. Application of the OGDHC coenzyme precursor thiamine rescued the activity of OGDHC and restored mitochondrial respiration. These effects were not mediated by changes in the expression of the OGDHC sub-units (E1k and E3), suggesting post-translational mechanism of thiamine effects. By the third day after TBI, thiamine treatment also decreased expression of TNF-R1. Specific markers of unfolded protein response did not change in response to thiamine. Conclusion and implicationsOur data point to OGDHC as a major site of damage in mitochondria upon traumatic brain injury, which is associated with neuroinflammation and can be corrected by thiamine. Further studies are required to evaluate the pathological impact of these findings in clinical settings.

A comparison of the local immune status between the primary and metastatic tumor in colorectal cancer: a retrospective study

BackgroundThe anticancer immune response has been reported to correlate with cancer progression. Tumor-infiltrating lymphocytes (TILs), which are one of the indicators of host immunity, affect the tumor growth, metastasis and chemoresistance. Both TILs in the primary tumor and those in the metastatic tumor have been reported to be a useful predictor of the survival and therapeutic outcome. However, the correlation between the density of TILs in the primary and metastatic tumor is unclear. The aim of this study was to elucidate the correlation between the density of TILs in the primary and metastatic tumor.MethodsA total of 24 patients with stage IV colorectal cancer who underwent concurrent resection of the primary tumor and liver metastasis were enrolled in order to assess the correlation between the density of TILs in the primary tumor and that in the metastatic tumor. Hematoxylin and eosin (HE)-stained tumor sections were used for the evaluation of TILs. The density of TILs was assessed by the measurement of the area occupied by mononuclear inflammatory cells over the total stromal area at the invasive margin. In addition, to evaluate TIL subsets and the activation/suppression status of the lymphocytes, immunohistochemistry for CD4, CD8, Forkhead boxprotein P3 (FOXP3), programmed cell death 1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 (CTLA4), inducible T-cell co-stimulator (ICOS), Glucocorticoid induced tumor necrosis factor receptor related protein (GITR), Human Leukocyte Antigen - antigen D Related (HLA-DR) and Granzyme B was performed, and the number of immunoreactive lymphocytes was counted.ResultsAccording to the evaluation using the HE-stained sections, the density of tumor-infiltrating mononuclear inflammatory cells in the primary tumor was significantly associated with that in the metastatic tumor. In addition, according to the immunohistochemistry evaluation, the density of CD4+, CD8+ and FOXP3+ TILs in the primary tumor and that in the metastatic tumor were significantly correlated with that in the metastatic tumor. Furthermore, the activation/suppression marker values of the lymphocytes (i.e., such as PD-1, ICOS, Granzyme B and the PD-1/CD8 ratio) in the primary tumor were correlated with values in the metastatic tumor.ConclusionsThe local immune status of the primary tumor was revealed to be similar to that of the metastatic tumor. This suggests that the evaluation of the local immunity of the primary tumor may be a substitute for the evaluation of the local immunity of the metastatic lesion. Therefore, information on the primary tumor may be useful when considering treatment strategies for metastatic lesions.

T‐cell intrinsic effects of GITR and 4‐1BB during viral infection and cancer immunotherapy

GITR [glucocorticoid inducible tumor necrosis factor receptor (TNFR)-related protein] and 4-1BB are costimulatory TNFR family members that are expressed on regulatory and effector T cells as well as on other cells of the immune system. Here we discuss the role of GITR and 4-1BB on T cells during viral infections and in cancer immunotherapy. Systemic treatment with agonistic anti-4-1BB antibody leads to a number of immune system abnormalities, and clinical trials of anti-4-1BB have been terminated. However, other modes of 4-1BB ligation may be less toxic. To date, similar toxicities have not been reported for anti-GITR treatment of mice, although anti-GITR antibodies can exacerbate mouse autoimmune models. Intrinsic effects of GITR and 4-1BB on effector T cells appear to predominate over their effects on other cell types in some models. Despite their similarities in enhancing T-cell survival, 4-1BB and GITR are clearly not redundant, and both pathways are required for maximal CD8(+) T-cell responses and mouse survival following severe respiratory influenza infection. GITR uses TNFR-associated factor (TRAF) 2 and TRAF5, whereas 4-1BB recruits TRAF1 and TRAF2 to mediate survival signaling in T cells. The differential use of signaling adapters combined with their differential expression may explain the non-redundant roles of GITR and 4-1BB in the immune system.

Expression of glucocorticoid induced tumor necrosis factor receptor ligand during acute rejection after rat liver transplantation

Objective To investigate te changes of glucocorticoid induced tumor necrosis factor receptor ligand (GITRL) in hepatic allograft rejection. Methods Liver transplantation from Lewis rats (n = 5 ) to Brown Norway (BN) rats was performed by Kamada' s two-cuff technique as acute rejection group. Liver transplantation from BN to BN rats ( n = 5 ) was performed as tolerance group. Recipients were sacrificed at 24th h postoperation. Blood samples were collected and grafts were harvested, then Kupffer cells were isolated. GITRL and tumor necrosis factor (TNF)-α protein expression in the hver was tested by immunohistochemistry, and the GITRL expression in Kupffer cells by immunocytochemistry. Enzyme linked immunosorbent assay (ELISA) was employed to detect the changes of TNF-α protein in the serum and supernatant. The staining intensity was analyzed by Image-Pro Plus 6. 0 image analysis software. Results At 24th h postoperation, the liver GITRL expression levels in tolerance and rejection groups were 0. 113 ± 0. 007 and 0. 270 ±0. 018, respectively (P ＜0. 05). The TNF-α expression levels in the liver in tolerance and rejection groups were 0. 114 ± 0. 004 and 0. 141 ± 0. 005 respectively ( P ＜ 0.05 ). The GITRL expression levels in Kupffer cells in tolerance and rejection groups were 0. 206 ±0. 017 and 0. 337 ±0. 018 respectively (P ＜0. 05 ). As compared with tolerance group (68. 66 ±21.12) ng/L, TNF-α protein expression levels were up-regulated in the supernatant of rejection group ( 178.33 ± 29. 39 ) ng/L ( P ＜ 0. 05 ).Conclusion The expression of GITRL in the liver and Kupffer cells was increased in the early stage of rejection, and monitoring and interfering GITRL may be useful for the early diagnosis and management of an acute rejection in liver transplantation. Key words: GITRL; Liver transplantation; Acute rejection; Kupffer cells

A preliminary study of chemo- and cytokine responses in rabies vaccine recipients of intradermal and intramuscular regimens

Plasma from 10 patients who had received rabies vaccine either intradermally (ID) or intramuscularly (IM) was examined for 20 chemo- and cytokines. Plasma samples were withdrawn on days 0, 3 and 7 after vaccination. These chemo- and cytokines and sampling days were chosen based on data collected from a protein array analysis of 122 cytokines conducted on one recipient of vaccine administered IM and one recipient of vaccine administered ID. Although eotaxin, interleukin (IL)-5 in the ID and IL-1 beta in the IM group were the only chemo- and cytokines that reached statistical significance ( p < 0.05), the overall trends may suggest bias on Th1 or Th2 according to vaccination routes. IL-1 alpha, -2, and -6, hemofiltrate cysteine–cysteine chemokine (HCC-4), glucocorticoid induced tumor necrosis factor receptor (GITR), tumor necrosis factor (TNF) related apoptosis inducing ligand-receptor (TRAIL-R3) had some degree of elevation in the ID group. TNF-alpha, gamma-interferon, granulocytes/macrophages – colony stimulating factor (GM-CSF), transforming growth factor (TGF)-beta, lymphotactin and pulmonary and activation-regulated chemokine (PARC) were elevated, although not to a significant level, in the IM group. IL-12, interferon-inducible T cell alpha chemoattractrant (I-TAC) and sertoli cell factor (SCF) were not significantly elevated in both groups whereas IL-4 and -10 were unchanged. Further studies are required to determine whether the presence of specific chemokines, such as eotaxin, is responsible for the production of high levels of rabies virus neutralizing antibody after administration of the dose-sparing ID regimen.

Regulatory T cells overturned: the effectors fight back

In the past 15 years, regulatory T cell (Treg) suppression has graduated from a phenomenon that 'dare not speak its name' to a field at the centre of a global research effort. It is now accepted that Tregs can target numerous cell populations to elicit potent immunosuppression. Intriguingly, emerging data suggest that certain signals can confer resistance to Treg suppression. Moreover, such resistance may be relevant to the pathogenesis of autoimmune diseases. In this article I review various pathways linked to resistance to Treg suppression. These include Toll-like receptor (TLR) signals, cytokines [in particular those that use the common gamma chain, such as interleukin (IL)-7 and IL-21] and the triggering of tumour necrosis factor (TNF) receptor family members (such as glucocorticoid induced tumor necrosis factor receptor (GITR), OX40 and 4-1BB). I also propose a model of 'tuned suppression' in which inflammatory stimuli and TLR ligation actively promote Treg function, such that as soon as effector cells re-acquire sensitivity to suppression the immune response can be efficiently curtailed.

Transplantation of Human Umbilical Mesenchymal Stem Cells from Wharton's Jelly after Complete Transection of the Rat Spinal Cord

BackgroundHuman umbilical mesenchymal stem cells (HUMSCs) isolated from Wharton's jelly of the umbilical cord can be easily obtained and processed compared with embryonic or bone marrow stem cells. These cells may be a valuable source in the repair of spinal cord injury.Methodology/Principal FindingsWe examine the effects of HUMSC transplantation after complete spinal cord transection in rats. Approximately 5×105 HUMSCs were transplanted into the lesion site. Three groups of rats were implanted with either untreated HUMSCs (referred to as the stem cell group), or HUMSCs treated with neuronal conditioned medium (NCM) for either three days or six days (referred to as NCM-3 and NCM-6 days, respectively). The control group received no HUMSCs in the transected spinal cord. Three weeks after transplantation, significant improvements in locomotion were observed in all the three groups receiving HUMSCs (stem cell, NCM-3 and NCM-6 days groups). This recovery was accompanied by increased numbers of regenerated axons in the corticospinal tract and neurofilament-positive fibers around the lesion site. There were fewer microglia and reactive astrocytes in both the rostral and caudal stumps of the spinal cord in the stem cell group than in the control group. Transplanted HUMSCs survived for 16 weeks and produced large amounts of human neutrophil-activating protein-2, neurotrophin-3, basic fibroblast growth factor, glucocorticoid induced tumor necrosis factor receptor, and vascular endothelial growth factor receptor 3 in the host spinal cord, which may help spinal cord repair.Conclusions/SignificanceTransplantation of HUMSCs is beneficial to wound healing after spinal cord injury in rats.

Expression of foxp3 and glucocorticoid induced tumor necrosis factor receptor mRNA of T regulatory cell in food allergy animal models

Expression of foxp3 and glucocorticoid induced tumor necrosis factor receptor mRNA of T regulatory cell in food allergy animal models

Extracorporeal Photochemotherapy Is Accompanied by Increasing Levels of Circulating CD4+CD25+GITR+Foxp3+CD62L+ Functional Regulatory T-Cells in Patients With Graft-Versus-Host Disease

Extracorporeal photochemotherapy (ECP) produces clinical improvements in refractory/resistant graft-versus-host disease (GvHD). Immunological mechanisms of ECP are still under investigation. We have evaluated the changes in frequency and immunophenotype of circulating regulatory T cells (T-regs) in 10 patients undergoing allogeneic hematopoietic stem cell transplantation, receiving ECP for acute (n=4) or chronic (n=6) GvHD. T-regs were monitored for expression of surface CD4, CD25, GITR, CD45RO, CD62L and intracytoplasmic Foxp3. T-regs were sorted by fluorescence-activated cell sorting to perform functional assays by interferon (IFN)-gamma enzyme-linked immunospot and real-time quantitative polymerase chain reaction (RQ-PCR) to measure Foxp3, transforming growth factor (TGF)-beta, and interleukin (IL)-10 mRNA. ECP was accompanied by a significant increase of CD4+CD25+ T-regs after six procedures, increasing from 8.9% to 29.1% of total CD4 (P<0.05), with a simultaneous increase of glucocorticoid induced tumor necrosis factor receptor expression on CD4+CD25+ cells (from 15% to 40.8%, P<0.05). This increase was sustained after 12 procedures. T-regs expressed high levels of CD62L, CD45RO, and Foxp3. Sorted CD4+CD25+ T-regs were potently inhibitory toward the CD4+CD25- fraction, when matched with an allogeneic target (IFN-gamma secretion was reduced by 79%). Trans-well experiments showed that cell-to-cell contact was necessary to exert inhibitory activity. RQ-PCR revealed a significant expression of Foxp3 in CD4+CD25+ T-regs, but there was virtually no detection of TGF-beta and IL-10. GvHD improved in all patients, allowing tapering or discontinuation of immunosuppressive drugs. Our study shows a time correlation between ECP and increasing percentages of circulating functional T-regs. Albeit suggestive, our results need to be confirmed on larger series to determine the actual role of T-reg in mediating the clinical effect of ECP.

5:58 138. The role of activation inducible tumor necrosis factor receptor and ligand in lumbar disc herniation

5:58 138. The role of activation inducible tumor necrosis factor receptor and ligand in lumbar disc herniation

Definition of target antigens for naturally occurring CD4+ CD25+ regulatory T cells

The antigenic targets recognized by naturally occurring CD4+ CD25+ regulatory T cells (T reg cells) have been elusive. We have serologically defined a series of broadly expressed self-antigens derived from chemically induced mouse sarcomas by serological identification of antigens by recombinant expression cloning (SEREX). CD4+ CD25+ T cells from mice immunized with SEREX-defined self-antigens had strong suppressive activity on peptide-specific proliferation of CD4+ CD25− T cells and CD8+ T cells. The suppressive effect was observed without in vitro T cell stimulation. Foxp3 expression in these CD4+ CD25+ T cells from immunized mice was 5–10 times greater than CD4+ CD25+ T cells derived from naive mice. The suppressive effect required cellular contact and was blocked by anti-glucocorticoid–induced tumor necrosis factor receptor family–related gene antibody. In vitro suppressive activity essentially disappeared 8 wk after the last immunization. However, it was regained by in vitro restimulation with cognate self-antigen protein but not with control protein. We propose that SEREX-defined self-antigens such as those used in this study represent self-antigens that elicit naturally occurring CD4+ CD25+ T reg cells.

Induction of nitric oxide synthase (NOS) by soluble glucocorticoid induced tumor necrosis factor receptor (sGITR) is modulated by IFN-gamma in murine macrophage.

Earlier study showed that glucocorticoid induced tumor necrosis factor receptor (GITR), a new TNFR family, activated murine macrophages to express inducible nitric oxide synthase (iNOS) and to generate nitric oxide (NO). A possible involvement of pro-inflammatory cytokines on NO production by GITR was investigated in vitro systems and signaling molecules contributing to sGITR-induced iNOS production are determined in Raw 264.7 cells, a murine macrophage cell line. The result showed that the synergy was afforded by the combination of GITR with IFN-g in a dose-dependent manner but IFN-gamma alone was not able to induce NOS. No effects were observed with TNF-alpha, IL-1beta, or IL-6 co-treated with GITR. To determine signaling molecules contributing to sGITR-induced iNOS production, a specific inhibitor for signal pathway proteins tested showed that PDTC (NF-kappaB) and genistein (tyrosine kinase) inhibited NOS induction significantly, while sodium orthovanadate (tyrosine phosphatase) potentiated NOS expression. These results suggest that activations of NF-kappaB were involved in induction of iNOS by GITR and IFN-gamma priming caused earlier and stronger NF-kappaB activation.

Apoptotic Response to 5-Fluorouracil Treatment Is Mediated by Reduced Polyamines, Non-Autocrine Fas Ligand and Induced Tumor Necrosis Factor Receptor 2

5-fluorouracil (5-FU) is the major chemotherapeutic agent for treatment of colorectal carcinoma, but the molecular mechanisms of response and resistance are not understood completely. We therefore studied the 5-FU dose response and time course of gene expression transcriptome changes in colon carcinoma cell lines that are relatively sensitive or resistant to 5-FU (RKO and HT29, respectively) in order to identify cellular pathways and corroborate functions of selected pathways. Expression of genes for polyamine biosynthesis, i.e. ornithine decarboxylase (ODC) and spermine and spermidine synthases, was repressed in the sensitive line, while the biosynthesis-inhibiting gene ODC antizyme was induced in the resistant line, and the rate-limiting gene in catabolism, spermine/spermidine acetyltransferase, was induced in both lines. Polyamine levels showed corresponding drastic decreases after 5-FU treatment, and polyamine replenishment interfered with 5-FU-induced apoptosis. In the sensitive cells which have wild-type p53, the p53 gene and its downstream genes including p21/WAF1, mdm2, Fas, mic-1, EphA2, and ferredoxin reductase as well as genes in the tumor necrosis factor (TNF) pathway including TNF receptor 2 (TNFR2) were induced, but not Fas ligand (FasL). Exposure to exogenous FasL increased 5-FU-induced apoptosis, and anti-TNFR2 antibody but not anti-TNFR1 partially protected the sensitive cells. Our combination of gene expression profiling and corroborative functional studies revealed that reduced polyamine levels, non-autocrine FasL originating exogenous to tumor cells, and induced TNFR2 are all functional mediators of apoptosis caused by 5-FU in colon carcinoma cells.

Soluble glucocorticoid-induced tumor necrosis factor receptor (sGITR) increased MMP-9 activity in murine macrophage.

Glucocorticoid induced tumor necrosis factor receptor (GITR), a new TNFR family, increased production of matrix matalloproteinase (MMP-9) in murine macrophages. Murine macrophages produced a band of gelatinolytic activity at 100 kDa when stimulated for 18 h with soluble GITR. MMP-9 was identified by gelatin zymography and Western blot. Previous results demonstrated that murine macrophages express GITR and GITR ligand constitutively. Induction of MMP-9 was synergistic with co-treatment of INF-gamma. MMPs could play a critical role in progression and promotion of tissue injury after inflammation stimulated by GITR/ligand system.