• 한국환경성돌연변이발암원학회지
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• 제24권2호
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• pp.91-98
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• 2004

Although 2,3,7,8-tetrachlorodibenzo-p-dioxin(TCDD) is a powerful carcinogen in several species, limited model system exist to study carcinogenicity of this compound at cellular level. To enhance our under-standing of carcinogenicity of TCDD at cellular level, we investigated micronucleus (MN) frequency as a index of genetic toxicity and whether TCDD can transform the human cells in culture. Normal human cell lines, skin keratinocyte HaCaT, Chang liver and breast MCF10A cells were used. TCDD did not affect the cell viability of the Chang liver, HaCaT and MCF10A cells. The frequency of micronucleus was increased after treatment of TCDD for 24hr in Chang liver and HaCaT cells, but not changed in MCF10A cells. And we observed putative transformed cells in Chang liver cells exposed to 1 $\mu$M TCDD for 2 weeks. The putative transformed cells were also observed in HaCaT cells with subsequent exposure to TCDD (0.1, 1, 10, 100 nM) for 2 weeks after initial exposure to MNNG, but not observed in MCF10A cells. Collectively, these results indicate that the ability of TCDD to induce micronuclei may be involved in cellular transformation of Chang liver and HaCaT cells. Our putative TCDD-transformed cells of Chang liver and HaCaT are expected to provide a clue to the elucidation of TCDD-induced transformation pathway.

• 대한의생명과학회지
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• 제27권4호
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• pp.329-333
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• 2021

We previously identified that tumor cells genetically modified with a 4-1BBL co-stimulatory molecule had anticancer effects in a CT26 mouse colorectal tumor model. To identify the distinction between immune cells in a mouse tumor model treated with tumor cells genetically modified with 4-1BBL or β-gal, we examined the immune cells in CT26-WT, CT26-βgal, and CT26-4-1BBL tumor bearing mice 21 days after tumor cell administration. The CD8+ T cells population in mice treated with tumor cells genetically modified with 4-1BBL was significantly increased on day 21 compared to that of tumor cells genetically modified with β-gal in the spleen and tumor tissue. The CD4+ T cell population was not different between the two mice groups. The Foxp3+CD25^high CD4 T cell population decreased on day 21 in tumor tissues, but the decrease was not significant. We also found that CD8 T cells had pivotal roles in inhibiting tumor growth by treating mice with ant-CD4 and CD8 antibodies. These results suggest that tumor cells genetically modified with 4-1BBL could inhibit tumor growth by affecting on CD8 T lymphocytes.

• 대한의생명과학회지
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• 제9권4호
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• pp.189-193
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• 2003

This study was undertaken to investigate the effect of baicalein, a major flavone component of Scutellaria balicalensis Georgi, on oxidant-induced cell injury in renal epithelial cells. Opossum kidney cells, an established proximal tubular epithelial cells, were used as a cell model of renal epithelial cells and t-butylhydroperoxide (tBHP) as an oxidant drug model. Cell viability was measured by MTT assay and lipid peroxidation was estimated by measuring the content of malondialdehyde, a product of lipid peroxidation. Exposure of cells to tBHP caused cell death and its effect was dose-dependent over concentration range of 0.1~1.0 mM. When cells were exposed to tBHP in the presence of various concentrations (0.1~10 $\mu$M) of baicalein, tBHP-induced cell death was prevented with a manner dependent of baicalein concentration. tBHP induced A TP depletion, which was significantly prevented by baicalein. Similarly, tBHP-induced DNA damage was prevented by baicalein. tBHP produced a marked increase in lipid peroxidation and its effect was completely inhibited by baicalein. These results indue ate that tBHP induces cell injury through a lipid peroxidation-dependent mechanism in renal epithelial cells, and baicalein prevented oxidant-induced cell injury via antioxidant action inhibiting lipid peroxidation. In addition, these results suggest that baicalein may be a candidate for development of drugs which are effective in preventing and treating renal diseases.

• IMMUNE NETWORK
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• 제14권5호
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• pp.227-236
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• 2014

Understanding germinal center reactions is crucial not only for the design of effective vaccines against infectious agents and malignant cells but also for the development of therapeutic intervention for the treatment of antibody-mediated immune disorders. Recent advances in this field have revealed specialized subsets of T cells necessary for the control of B cell responses in the follicle. These cells include follicular regulatory T cells and Qa-1-restricted cluster of differentiation $(CD)8^+$ regulatory T cells. In this review, we discuss the current knowledge related to the role of regulatory T cells in the B cell follicle.

• IMMUNE NETWORK
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• 제23권1호
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• pp.11.1-11.11
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• 2023

Memory T cells that mediate fast and effective protection against reinfections are usually generated upon recognition on foreign Ags. However, a "memory-like" T-cell population, termed virtual memory T (T_VM) cells that acquire a memory phenotype in the absence of foreign Ag, has been reported. Although, like innate cells, T_VM cells reportedly play a role in first-line defense to bacterial or viral infections, their protective or pathological roles in immune-related diseases are largely unknown. In this review, we discuss the current understanding of T_VM cells, focusing on their distinct characteristics, immunological properties, and roles in various immune-related diseases, such as infections and cancers.

• IMMUNE NETWORK
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• 제22권5호
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• pp.39.1-39.18
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• 2022

RNA metabolism plays a central role in regulating of T cell-mediated immunity. RNA processing, modifications, and regulations of RNA decay influence the tight and rapid regulation of gene expression during T cell phase transition. Thymic selection, quiescence maintenance, activation, differentiation, and effector functions of T cells are dependent on selective RNA modulations. Recent technical improvements have unveiled the complex crosstalk between RNAs and T cells. Moreover, resting T cells contain large amounts of untranslated mRNAs, implying that the regulation of RNA metabolism might be a key step in controlling gene expression. Considering the immunological significance of T cells for disease treatment, an understanding of RNA metabolism in T cells could provide new directions in harnessing T cells for therapeutic implications.

• The Korean Journal of Physiology and Pharmacology
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• 제16권4호
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• pp.243-247
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• 2012

Recent studies suggest that immunization with autologous dendritic cells (DCs) results in protective immunity and rejection of established tumors in various human malignancies. The purpose of this study is to determine whether DCs are generated from peripheral blood mononuclear cells (PBMNs) by using cytokines such as F1t-3 ligand (FL), granulocyte macrophage-colony stimulating factor (GM-CSF), IL-4, and TNF-${\alpha}$, and whether cytotoxic T cells activated against the thyroid cancer tissues by the DCs. Peripheral blood was obtained from 2 patients with thyroid cancer. DCs were established from PBMNs by culturing in the presence of FL, GM-CSF, IL-4, and TNF-${\alpha}$ for 14 days. At day 14, the differentiated DCs was analyzed morphologically. The immunophenotypic features of DCs such as CDla, CD83, and CD86 were analyzed by immunofluorelescence microscopy. At day 18, DCs and T cells were incubated with thyroid cancer tissues or normal thyroid tissues for additional 4 days, respectively. DCs generated from the PBMNs showed the typical morphology of DCs. Activated cytotoxic T lymphocytes (CTLs) were observed also. DCs and the CTLs were attached to the cancer tissues on scanning electron microscope. The DCs activated the CTLs, which able to specifically attack the thyroid cancer. This study provides morphologic evidence that the coculture of T cells/cancer tissues activated the T cells and differentiated CTLs. The CTLs tightly adhered to cancer tissues and lysed cancer tissues vigorously. Therefore DCs could be used as potential vaccines in the immunotherapy.

• 동의생리병리학회지
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• 제21권2호
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• pp.438-443
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• 2007

The purpose of this research is to examine the effects of Kamijihwang-tang(KJHT) on CD+4 T cells and CD8+ T cell ovalbumin (OVA)-induced asthmatic mice. C57BL/6 mice were injected, inhaled and sprayed with OVA for 12 weeks (four a week) for asthma induction. Two experimental groups were treated with different concentrations of KJHT (400 mg/kg and 200 mg/kg) extract and cyclosporine A (10 mg/kg) for the later 8 weeks. At the end of the experiment, the mice lung, peripheral lymph node (PLN), and spleen were removed and CD4+ T cells and CD8 + T cells for analyzed by flow cytometer. Number of CD4+ T cells in lung, PLN, spleen of the KJHT group (400 mg/kg) were significantly decreased compared with that of control group. Number of CD8+ T cells in lung, PLN, spleen of the KJHT group (200 mg/kg) were significantly decreased compared with that of control group. The results of this study suggest that KJHT alleviated asthmatic hyperactivity through CD4+ and CD8+ T cells. Further study of relative cytokines is expected.

• IMMUNE NETWORK
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• 제11권5호
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• pp.299-306
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• 2011

Background: $CD4^+Fop3^+$ regulatory T cells (Tregs) are needed to maintain peripheral tolerance, but their role in the development of autoimmune arthritis is still debated. The present study was undertaken to investigate the mechanism by which Tregs influence autoimmune arthritis, using a mouse model entitled K/BxN. Methods: We generated Treg-deficient K/BxNsf mice by congenically crossing K/BxN mice with Foxp3 mutant scurfy mice. The arthritic symptoms of the mice were clinically and histopathologically examined. The proportions and activation of $CD4^+$ T cells and/or dendritic cells were assessed in the spleens, draining lymph nodes and synovial tissue of these mice. Results: K/BxNsf mice exhibited earlier onset and more aggressive progression of arthritis than their K/BxN littermates. In particular, bone destruction associated with the influx of numerous RANKL+ cells into synovia was very prominent. They also contained more memory phenotype $CD4^+$ T cells, more Th1 and Th2 cells, and fewer Th17 cells than their control counterparts. Plasmacytoid dendritic cells expressing high levels of CD86 and CD40 were elevated in the K/BxNsf synovia. Conclusion: We conclude that Tregs oppose the progression of arthritis by inhibiting the development of $RANKL^+$ cells, homeostatically proliferating $CD4^+$ T cells, Th1, Th2 and mature plasmacytoid dendritic cells, and by inhibiting their influx into joints.

• Clinical and Experimental Pediatrics
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• 제54권4호
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• pp.157-162
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• 2011

Purpose: Exaggerated pro-inflammatory reactions during the acute phase of Kawasaki disease (KD) suggest the role of immune dysregulation in the pathogenesis of KD. We investigated the profiles of T regulatory cells and their correlation with the clinical course of KD. Methods: Peripheral blood mononuclear cells were collected from 17 KD patients during acute febrile and subacute afebrile phases. T cells expressing CD4, CD25, and Foxp3 were analyzed using flow cytometry, and the results were correlated with the clinical course of KD. Results: The percentage of circulating $CD4^+CD25^{high}Foxp3^+$ T cells among $CD4^+$ T cells was Significantly higher during the subacute afebrile phase than during the acute febrile phase ($1.10%{\pm}1.22%$ vs. $0.55%{\pm}0.53%$, P=0.049). Although levels of $CD4^+CD25^{low}Foxp3^+$ T cells and $CD4^+CD25^-Foxp3^+$ T cells were only slightly altered, the percentage of $CD4^+CD25^+Foxp3^-$ T cells among $CD4^+$ T cells was significantly lower during the subacute afebrile phase than during the acute febrile phase ($2.96%{\pm}1.95%$ vs. $5.64%{\pm}5.69%$, P=0.036). Consequently, the ratio of $CD25^{high}Foxp3^+$ T cells to $CD25^+Foxp3^-$ T cells was higher during the subacute afebrile phase than during the acute febrile phase ($0.45%{\pm}0.57%$ vs. $0.13%{\pm}0.13%$, P=0.038). Conclusion: Decreased $CD4^+CD25^{high}Foxp3^+$ T cells and/or an imbalanced ratio of $CD4^+CD25^{high}Foxp3^+$ T cells to $CD4^+CD25^+Foxp3^-$ T cells might playa role in KD development. Considering that all KD patients were treated with intravenous immunoglobulin (IVIG), recovery of $CD4^+CD25^{high}Foxp3^+$ T cells during the subacute afebrile phase could be a mechanism of IVIG.