Regulatory T Cells in Tumor Microenvironment and Approach for Anticancer Immunotherapy

Tregs have a role in immunological tolerance and immune homeostasis by suppressing immune reactions, and its therapeutic potential is critical in autoimmune diseases and cancers. There have been multiple studies conducted on Tregs because of their roles in immune suppression and therapeutic potential. In tumor immunity, Tregs can promote the development and progression of tumors by preventing effective anti-tumor immune responses in tumor-bearing hosts. High infiltration of Tregs into tumor tissue results in poor survival in various types of cancer patients. Identifying factors specifically expressed in Tregs that affect the maintenance of stability and function of Tregs is important for understanding cancer pathogenesis and identifying therapeutic targets. Thus, manipulation of Tregs is a promising anticancer strategy, but finding markers for Treg-specific depletion and controlling these cells require fine-tuning and further research. Here, we discuss the role of Tregs in cancer and the development of Treg-targeted therapies to promote cancer immunotherapy.

Regulatory T Cells in Tumor Microenvironment and Approach for Anticancer Immunotherapy

Tregs have a role in immunological tolerance and immune homeostasis by suppressing immune reactions, and its therapeutic potential is critical in autoimmune diseases and cancers. There have been multiple studies conducted on Tregs because of their roles in immune suppression and therapeutic potential. In tumor immunity, Tregs can promote the development and progression of tumors by preventing effective anti-tumor immune responses in tumor-bearing hosts. High infiltration of Tregs into tumor tissue results in poor survival in various types of cancer patients. Identifying factors specifically expressed in Tregs that affect the maintenance of stability and function of Tregs is important for understanding cancer pathogenesis and identifying therapeutic targets. Thus, manipulation of Tregs is a promising anticancer strategy, but finding markers for Treg-specific depletion and controlling these cells require fine-tuning and further research. Here, we discuss the role of Tregs in cancer and the development of Treg-targeted therapies to promote cancer immunotherapy.

Regulatory T Cells in Tumor Microenvironment and Approach for Anticancer Immunotherapy

Tregs have a role in immunological tolerance and immune homeostasis by suppressing immune reactions, and its therapeutic potential is critical in autoimmune diseases and cancers. There have been multiple studies conducted on Tregs because of their roles in immune suppression and therapeutic potential. In tumor immunity, Tregs can promote the development and progression of tumors by preventing effective anti-tumor immune responses in tumor-bearing hosts. High infiltration of Tregs into tumor tissue results in poor survival in various types of cancer patients. Identifying factors specifically expressed in Tregs that affect the maintenance of stability and function of Tregs is important for understanding cancer pathogenesis and identifying therapeutic targets. Thus, manipulation of Tregs is a promising anticancer strategy, but finding markers for Treg-specific depletion and controlling these cells require fine-tuning and further research. Here, we discuss the role of Tregs in cancer and the development of Treg-targeted therapies to promote cancer immunotherapy.

C-Reactive Protein to Serum Albumin Ratio Is an Independent Predictor of All-Cause Mortality in Patients with ANCA-Associated Vasculitis

PURPOSE: We investigated whether C-reactive protein (CRP) to serum albumin ratio (CAR) could be an independent predictor of all-cause mortality in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). MATERIALS AND METHODS: We retrospectively reviewed the medical records of 170 patients with AAV. We collected clinical and laboratory data. We also examined AAV-related and traditional risk factors of all-cause mortality. To assess the hazard ratios of variables, we performed univariable and multivariable Cox hazard model analyses. RESULTS: The mean age was 55.0 years and 53 patients (31.2%) were male among 170 patients with AAV (88 microscopic polyangiitis, 43 granulomatosis with polyangiitis, and 39 eosinophilic granulomatosis with polyangiitis). ANCA was detected in 129 patients (75.9%). The initial mean CRP and serum albumin were 41.1 (mg/L) and 3.6 (g/dL), and the mean CAR at diagnosis was 14.8. The most common risk factor of mortality was hypertension (42.4%), followed by chronic kidney disease ≥stage 3 (25.9%). Fourteen patients (8.2%) died during the mean follow-up of 56.7 months. In both multivariable Cox hazard model analyses, CAR at diagnosis was identified as an independent predictor of all-cause of mortality comparable to diabetes mellitus (DM). Moreover, patients with CAR ≥10.35 and having DM exhibited a higher frequency of all-cause mortality than those without. CONCLUSION: CAR at diagnosis can be an independent predictor of all-cause mortality, comparable to DM, the conventional risk factor of mortality.

Calpains are Involved in Entamoeba histolytica-Induced Death of HT-29 Colonic Epithelial Cells

Entamoeba histolytica is an enteric tissue-invading protozoan parasite that can cause amebic colitis and liver abscess in humans. E. histolytica has the capability to kill colon epithelial cells in vitro; however, information regarding the role of calpain in colon cell death induced by ameba is limited. In this study, we investigated whether calpains are involved in the E. histolytica-induced cell death of HT-29 colonic epithelial cells. When HT-29 cells were co-incubated with E. histolytica, the propidium iodide stained dead cells markedly increased compared to that in HT-29 cells incubated with medium alone. This pro-death effect induced by ameba was effectively blocked by pretreatment of HT-29 cells with the calpain inhibitor, calpeptin. Moreover, knockdown of m- and micro-calpain by siRNA significantly reduced E. histolytica-induced HT-29 cell death. These results suggest that m- and micro-calpain may be involved in colon epithelial cell death induced by E. histolytica.

T Cell-specific Immunosuppression Using Tautomycetin or PTD-conjugated Protein Drugs

No abstract available.

The Effects of Prolonged Exercise on Blood Lipid Levels and Immune Response in RICO RAT / 대한면역학회지

No abstract available.

Supplement of Incomplete Apoptosis Through CD8/Fas Chimeric Molecule by PMA of IFN-gamma / 대한면역학회지

No abstract available.

Immunosuppressive Effects of Tautomycetin on T Cells / 대한면역학회지

T cell activation is a critical event for initiation and regulation of immune responses and inhibitors of such signaling pathways are clinically useful for the treatment of patients received allogratt and autoimmune disease. In the course of screening soil microorganisms from the forest of Cheju island in Korea for new immunosuppressive agent, one of Streptomyces species (CK-95441) was found to produce a new immunosuppressant, tautomycetin which also had antifungal activity. Tautomycetin showed the inhibition of T cell proliferation in murine mixed lymphocyte reaction (MLR) and T cell activation induced by concanavalin A. Tautomycetin also blocked the induction of IL-2 gene expression which was examined in Jurkat TAg cell line in which multiple NFAT-binding sites and minimal IL-2 promoter drive the production of B-galactosidase. Also, the level of inhibition in activation-induced IL-2 receptor expression by tautomycetin was greater than those by cyclosporin A measured by flow cytometry. But, Fas ligand-induced apoptosis in Jurkat cells was unaffected by tautomycetin which was measured by DNA fragmentation assay. These results suggested that tautomycetin will be able to be used as a potent immunosuppressive drug following organ transplantation.

Functions of Ich-1(L). and Ich-1(S) in Apoptotic Signaling Pathway of jurkat T Cells / 대한면역학회지

Human caspase-2, Ich-1 (Ice and Ced-3 homolog), has two different forms of mRNA species derived from alternative splicing, which encodes Ich-1 and Ich-1s. Ich-1v which induces apoptosis is antagonist of Ich-1s which suppresses Rat-1 cell death by serum deprivation. To investigate functions of Ich-1 and Ich-1s in T celi apoptosis, the fusion DNA constructs were made with the ecto and transmembrane of CDB and Ich-lv or Ich-1s and CDS-Ich-1 or CD8-Ich-1s chimeric protein was transiently expressed on Jurkat T cells. Tyrosine phosphorylation of intracellular proteins was induced in these transfectans when activated shortly by anti-CDB Ab. CDB-Ich-li transfectant in serum-rich condition and CDB-Ich-ls transfectant in serum-deprived condition underwent apoptosis when treated with anti-CDS Ab or incubated with NIH3T3 cells expressing stably Fas-L on their surface. We also made six antisense DNA constructs which could specifically inhibit the expression of Ich-1v, Ich- 1s, and then they were transiently transfected into Jurkat T cell. The overexpression of both of the antisese- Ich-1 against N-terminal 42 bp and against C-terminal 366 bp inhibited apoptosis through Fas signalling. But, when three different forms of antisense-Ich-1s were overexpressed in their transfectants, antisense-DNA against N-terminal 197 bp increased knd the one against C-terminal 66 bp inhibited apoptosis, instead the full size of antisense-DNA did not give any effects on apoptosis through Fas pathway.

Okadaic Acid, RK682 and Calyculin Modulate TcR - Mediated Signaling Events / 대한면역학회지

The T cell antigen receptor (TcR) in combination with costimulatory signals triggered by accessory molecules present on the surface of the antigen-presenting cells (APC) regulates the activation and growth of T lymphocytes. Calyculin A and Okadaic acid is known to be an inhibitor of serine/threonine phosphatase and RK-682 specifically blocks functions of tyrosine phosphatase. To investigate roles of these inhibitors in TcR-mediated signaling cascade, chimeric molecule CD8-5 which contains the extracellular and transmembrane domains of the human CD8a molecule and the cytoplasmic tail of TcR 5 chain were stably expressed in Jurkat cell line. CD8-5 chimeric protein induced tyrosine phosphorylation of various cytoplasmic substrates and IL-2 gene expression in a NFAT dependent manner by stimulation with anti-CD8 mAb OKT8 as seen in TcR stimulation. When CD8-5 transfectants were preincubated with Okadaic acid, Calyculin or RK682, they differentially affected tyrosine phosphorylation of signaling mediators including CD8-5 molecule. When Jurkat Tag cell line was used where SV40 T antigen is stably expressed and the expression of p-galactosidase is driven by the multiple NFAT binding sites plus minimal IL-2 promoter, these phosphatase inhibitors -RK682, Calyculin A, Okadaic acid- effectively inhibited IL-2 gene expression at the concentration of 1.2832 x 10 ' M, 3.9924 x 10 M, 7.2707 x 10 M respectively. These results suggested that Okadaic acid, Calyculin or RK682 modulate TcR-proximal as well as TcR-distal signaling events during T cell activation.

A Novel Cell Line for Screening of Immunosuppressor Specific to T Lymphocytes / 대한면역학회지

The systematic study of products from bacteria and fungi has led to the development of two immunosuppressive drugs, cyclosporin A and FK 506 (tacrolimus) which are useful to suppress adaptive immune responses to the grafted tissue. However, they affect all immune responses indiscriminately and are both toxic to kidneys and other organs. To facilitate the development of immunosuppressor to block the T cell receptor (TcR)-mediated signaling cascade specifically, a novel Jurkat T cell transfectants, JK NFAT-SEAP were generated in which the expression of the secreted alkaline phosphatase (SEAP) is driven by the multiple NFAT binding sites plus minimal IL-2 promoter. Upon stimulation with ionomycin or anti-TcR mAb OKT3 in the presence of PMA, these transfectants secreted high level of SEAP into the medium, which was conveniently analyzed by SEAP analysis. The secretion of SEAP was effectively inhibited by cyclosporin A or FK 506 at the concentration of [10 ' ug/ml], [10 ug/ml] respectively. JK NFAT-SEAP transfectants will provide two major advantages for the development of a novel immunosuppressor. First, analysis of SEAP secreted into the culture medium by SEAP analysis enables us to test a large number of samples within a short period of time. Second, Usage of IL-2 promoter for the expression of SEAP makes us identify bioproducts to target specifically on TcR-mediated signaling pathway.