• IMMUNE NETWORK
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• v.5 no.1
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• pp.16-22
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• 2005

Background: IL-18 was originally cloned as a IFN-${\gamma}$ inducing factor in primed T cells. In synergy with IL-12, IL-18 has been shown to induce strikingly high levels of IFN-${\gamma}$ production by T cells and to enhance Th1 development. Also this cytokine exerts induction of Th2 development through IL-4 induction. Methods: Resting $CD4^+$ T cells were sorted by negative selection and activated by anti-CD3 plus anti-CD28 Ab. Expression of IL-12 binding sites, IL-18 binding sites, IL-18R ${\alpha}$, and GATA-3 mRNA were analysed by FACS and RT-PCR, respectively. Results: Resting $CD4^+$ T cells expressed IL-18R ${\alpha}$ chain but not IL-18 binding sites, suggesting a lack of IL-18R ${\beta}$ expression. IL-18R ${\alpha}$ was maintained on the Th1 and Th2 committed cells. IL-18 binding sites were induced on the Th1 but not Th2 cells. Exposure of these cells to IL-18 led to up-regulation of GATA-3 mRNA expression only in Th2 committed cells. To elucidate the relationship between IL-18R ${\alpha}$ expression and GATA-3 induction by IL-18, Th1 and Th2 committed cells were further cultured in medium with or without IL-12 for 2 days. IL-12 binding sites were maintained on the Th1 and Th2 cells regardless of IL-12 treatment, but IL-18R a expression was rapidly down-regulated on the IL12-untreated Th2 cells which did not induce GATA-3 mRNA expression followed by IL-18 stimulation. Conclusion: IL-12 supports expression of IL-18R ${\alpha}$ and GATA-3 mRNA expression was induced by IL-18 through IL-18R ${\alpha}$ without expression of IL-18 binding site in Th2 cells.

• 한국생물공학회:학술대회논문집
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• 2001.11a
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• pp.193-196
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• 2001

IL-18. formerly known as IGIF(interferon -gamma inducing factor), is structurally IL-l related but functionally IL-12 related pro-inflammatory cytokine. The human IL -18(hIL-lS), like IL-$1{\beta}$, is synthesized as a biologically inactive precursor of 24kDa lacking a signal peptide, and then cleaved into an active mature form by cystein protease IL-$1{\beta}$ converting enzyme (ICE: caspase- 1), We tested if the mature hIL -18 can be expressed and secreted into culture medium by transforming the forming gene construct consisting of a mature hIL-18 gene fused to signal peptide of rice amylase lA. Secondly, we were tested if the pro- IL-18 could be processed into a biologically active form by caspase-l like protease in plant. Cell suspension culture was established from the leaf-derived calli of transgenic tobacco plant. Southern and Northern blot analysis indicated the expression of both pro-hIL-18 and mature hIL-18 plant cells. Western blot analysis introduced the protein products of pro- hIL -18 and mhIL -18 were observed in transigenic cell lines. In addition, the molecular size of recombinant pro-hILl-18 and mhIL-18 were estimated to be 24kDa and 18kDa, respectively. ELISA revealed that the amount of pro- hIL -18 was 1.3ug per gram of fresh weight calli. Moreover, the presence of mhIL-18 was detected in the culture medium and it appeared to be 25ug/L.

• Journal of Yeungnam Medical Science
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• v.24 no.1
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• pp.67-78
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• 2007

Background : Interleukin-18 (IL-18) is one of the principal inducers of interferon-${\gamma}$ (IFN-${\gamma}$) in lymphocytes. Materials and Methods : The effect of IL-18 on the expression of chemokine IP-10(CXCL10) mRNA in C57BL/6 mouse peritoneal macrophages was studied by using Northern blot analysis, enzyme linked immunosobent assay and electrophoretic mobility shift assay. Results : IL-18 was determined to exert no direct effect on the expression of IP-10(CXCL10) mRNA. However, IL-18 pretreatment was determined to play a cooperative role in the synergistic induction of LPS-induced IP-10(CXCL10) mRNA expression. The effect associated with IL-18 pretreatment with regard to the synergistic induction of LPS-induced IP-10 (CXCL10) mRNA expression was detected after 16 hr of IL-18 pretreatment, administered prior to LPS stimulation. The pattern of NF-${\kappa}B$ binding activity during IL-18 pretreatment with LPS stimulation was found to coincide with the expression of IP-10(CXCL10) mRNA. Conclusion : Although IL-18 alone exerts no direct effect on the expression of chemokine IP-10(CXCL10), a definite period of IL-18 pretreatment induces the synergistic expression of LPS-induced IP-10(CXCL10) mRNA. NF-${\kappa}B$ activation is a component of this synergistic effect of IL-18 pretreatment. These results provide useful information, which may facilitate the elucidation of the action mechanisms underlying IL-18 effect on the expression of IP-10(CXCL10) mRNA.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.18
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• pp.7857-7861
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• 2014

Natural killer (NK) cells play an important role in anti-tumor immunity. Interleukin (IL)-18 is an immunoregulatory cytokine that induces potent NK cell-dependent anti-tumor responses when administrated with other cytokines. In this study, we explored the effects of combining IL-18 and IL-2 on NK cytotoxicity as well as expression levels of the NK cell receptor NKG2D in vitro. Freshly isolated PBMCs were incubated for 48 h with IL-18 and IL-2, then CD107a expression on $CD3^-CD56^+$ NK cells was determined by three-colour flow cytometry to evaluate the cytotoxicity of NK cells against human erythroleukemia K562 cells and human colon carcinoma HT29 cells. Flow cytometric analysis was also employed to determine NKG2D expression on NK cells. The combined use of IL-18 and IL-2 significantly increased CD107a expression on NK cells compared with using IL-18 or IL-2 alone, suggesting that the combination of these two cytokines exerted synergistic enhancement of NK cytotoxicity. IL-18 also enhanced NKG2D expression on NK cells when administered with IL-2. In addition, blockade of NKG2D signaling with NKG2D-blocking antibody attenuated the up-regulatory effect of combining IL-18 and IL-2 on NK cytolysis. Our data revealed that IL-18 synergized with IL-2 to dramatically enhance the cytolytic activity of human NK cells in a NKG2D-dependent manner. The results appear encouraging for the use of combined IL-18 and IL-2 in tumor immunotherapy.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5353-5361
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• 2012

Interleukin-18 (IL-18) is an immune-stimulatory cytokine with antitumor activity in preclinical models. It plays pivotal roles in linking inflammatory immune responses and tumor progression and is a useful candidate in gene therapy of lymphoma or lymphoid leukemia. A phase I study of recombinant human IL-18 (rhIL-18) in patients with advanced cancer concluded that rhIL-18 can be safely given in biologically active doses to patients with advanced cancer. Some viruses can induce the secretion of IL-18 for immune evasion. The individual cytokine activity might be potentiated or inhibited by combinations of cytokines. Here we focus on combinational effects of cytokines with IL-18 in cancer progression. IL-18 is an important non-invasive marker suspected of contributing to metastasis. Serum IL-18 may a useful biological marker as independent prognostic factor of survival. In this review we cover roles of IL-18 in immune evasion, metastasis and angiogenesis, applications for chemotherapy and prognostic or diagnostic significance.

• Journal of Microbiology and Biotechnology
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• v.16 no.10
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• pp.1605-1612
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• 2006

Interleukin (IL)-18, a member of the family of IL-l cytokine, is one of the principal inducers of $interferon-{\gamma}(IFN-{\gamma})$ in T lymphocytes and natural killer cells. The objective of the present study was to evaluate the effect of IL-18 on the expression of chemokine IP-10 (CXCL-10) mRNA in mouse peritoneal macrophages. IL-18 had very weak direct effect or synergistic effect with IL-12 on the expression of IP-10 mRNA in C57BL/6 mouse peritoneal macrophages. However, IL-18 pretreatment was found to playa cooperative role in the expression of lipopolysaccharide (LPS)-induced IP-10 mRNA. For the expression of LPS-induced IP-10 mRNA, the synergistic effect was detected after 16 h of IL-18 pretreatment prior to LPS stimulation. The expression level of CD14 in cells stimulated with LPS was not changed by IL-18 pretreatment, and the level of $IFN-{\gamma}$ production during IL-18 pretreatment plus LPS stimulation was barely discernible ($0.36{\pm}0.31pg/ml$). Namely, the synergistic effect of IL-18 pretreatment was not related to a change of LPS receptor, CD14 expression, and the production of $IFN-{\gamma}$ by the interaction between IL-18 and LPS. The synergistic effect of IL-18 pretreatment on the expression of LPS-induced IP-10 was related to not NF-kB but AP-1 activation, and associated with the extracellular signal-regulated kinase (ERK) pathway, one of the mitogen-activated protein kinase signaling pathways. These results provide useful information that may elucidate the mechanisms underlying the effect of IL-18 on the expression of IP-10 mRNA.

• Proceedings of the PSK Conference
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• 2003.04a
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• pp.80-81
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• 2003

IL-18 has been found to have multiple effects upon various cells involved in tumor immunology. Here, we discuss opposite effects of IL-18 in tumor immunology. IL-18 has been shown that it has significant anti-tumor effects, which are mediated by T cells and NK cells, in a manner similar to IL-12. First, we investigated the evaluation of the effects of the systemic administration of IL-18 in combination with B7-1 (CD80) against murine B16 melanoma in vivo. (omitted)

• IMMUNE NETWORK
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• v.14 no.3
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• pp.149-155
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• 2014

We performed this study to evaluate the role of Interleukin-17 (IL-17) and Interleukin-18 (IL-18) in insulin resistance during normal pregnancy. This descriptive cross sectional study was carried out on 97 healthy pregnant women including 32, 25, and 40 individuals in the first, second, and third trimesters, respectively, and on 28 healthy non pregnant women between the autumn of 2012 and the spring of 2013. We analyzed the serum concentrations of IL-17 and IL-18 by using the enzyme linked immunosorbent assay (ELISA). Insulin resistance was measured by homeostasis model assessment of insulin resistance equation. No significant differences between the demographic data of the pregnant and non pregnant groups were observed. Insulin resistant in pregnant women was significantly higher than the controls (p=0.006). Serum IL-17 concentration was significantly different in non pregnant women and pregnant women in all gestational ages (p<0.05). Serum IL-18 level was significantly lower in subjects with first, second, and third trimesters of pregnancy in compared to non pregnant women (p<0.05). No significant correlations were found between serum IL-17 and IL-18 levels with insulin resistance (r=0.08, p=0.34 vs. r=0.01, p=0.91, respectively). Our data suggested that IL-17 and IL-18 do not appear to attribute greatly to pregnancy deduced insulin resistance during normal pregnancy.

• Proceedings of the Microbiological Society of Korea Conference
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• 2004.05a
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• pp.97-97
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• 2004

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1365-1370
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• 2012

The high mobility group box-1 (HMGB1) protein and NALP3 inflammasome have been identified to play important roles in inflammation and cancer pathogenesis, but the relationships between the two and cancer remain unclear. The current study investigated the relationship between HMGB1 and the NALP3 inflammasome in THP-1 macrophages. HMGB1 was found unable to activate the NALP3 inflammasome and failed to induce the release of the IL-$1{\beta}$ and IL-18 in THP-1 macrophages. HMGB1 was also found significantly enhanced the activity of ATP to induce IL-$1{\beta}$ and IL-18 by the induction of increased expression of pro-IL-$1{\beta}$ and pro-IL-18. This process was dependent on activation of RAGE, MAPK p38 and NF-${\kappa}B$ signaling pathway. These results demonstrate that HMGB1 promotes the synthesis of pro-IL-$1{\beta}$ and pro-IL-18 in THP-1 macrophages by the activation of p38 MAPK and NF-${\kappa}B$ through RAGE. HMGB1 likely plays an important role in the first step of the release of the IL-$1{\beta}$ and IL-18, preparing for other cytokines to induce excessive release of IL-$1{\beta}$ and IL-18 which promote inflammation and cancer progression.