• Korean Journal of Transplantation
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• v.28 no.3
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• pp.113-120
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• 2014

Two-signal models are useful in explaining various types of immune responses. In particular, secondary, so-called costimulatory, signals are critically required for the process of T-cell activation, survival, differentiation, and memory formation. Early studies in rodent models showed that targeting T-cell costimulatory pathways elicits immunological tolerance, providing a basis for development of costimulatory therapeutics in allograft rejection. However, as the classic definition of T-cell costimulation continues to evolve, simple blockade of costimulatory pathways has limitations in prevention of allograft rejection. Furthermore, functions of costimulatory molecules are much more diverse than initially anticipated and beyond T cells. In this mini-review, we will discuss CD137-CD137L bidirectional signals as examples showing that two-signals can be applicable to multiple phases of immune responses.

• IMMUNE NETWORK
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• v.1 no.2
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• pp.95-103
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• 2001

T cells play a central role in the initiation and regulation of the immune response to foreign antigens. Full activation of T cells requires the engagement of T cell receptor complex (TCR) and the binding of a second costimulatory receptor to its ligand expressed on antigen presenting cells (APC). Among the molecules known to provide costimulatory function, CD28 has been the most dominant and potent costimulatory molecule. However, the function of CD28 is becoming more complex due to the recent discovery of its structural homologue, CTLA-4 and ICOS. This review summarizes the biology and physiologic function of each of these receptors, and further focuses on the biochemical mechanism underlying the function of these receptors. Complete understanding of the CD28/CTLA-4/ICOS costimulatory pathway will provide the basis for developing new therapeutic approaches for immunological dieseases.

• BMB Reports
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• v.46 no.9
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• pp.448-453
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• 2013

CpG-DNA has various immunomodulatory effects in dendritic cells, B cells, and macrophages. While induction of cytokines by CpG-DNA has been well documented in macrophages, the expression of costimulatory molecules in CpG-DNA treated macrophages has not yet been defined. Therefore, we investigated the effects of CpG-DNA on the expression of costimulatory molecules in RAW 264.7 cells. The surface expression of CD80 was slightly increased and CD83 expression was significantly increased in response to CpG-DNA. However, the expression of CD86 and MHC class II was not changed. As expression of CD83 mRNA was also increased by CpG-DNA, CD83 expression is regulated at a transcriptional level. To understand the contribution of signaling pathways to CD83 induction, we used pathway specific inhibitors. The NF-${\kappa}B$ inhibitor significantly reduced surface expression of CD83 as well as phagocytic activity of RAW 264.7 cells. Therefore, CD83 expression may contribute to the immunostimulatory effects of CpG-DNA in macrophage cells.

• IMMUNE NETWORK
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• v.14 no.5
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• pp.260-264
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• 2014

ZYM-201 is a methyl ester of triterpenoid glycoside from Sanguisorba officinalis which has been used for treatment of inflammatory and metabolic diseases. In this study, immunomodulatory effects of ZYM-201 on B cells were examined in vitro and in vivo. When splenocytes were activated with lipopolysaccharide (LPS), the major population which had shown an increase in cell numbers was B cells. However, when the B cells were treated with ZYM-201 after LPS activation, their cell numbers and the expression of major costimulatory molecules, CD80 and CD86, were decreased. Furthermore, the effect of LPS, which induces activation of NF-${\kappa}B$, was abolished by ZYM-201: LPS-stimulated B cells showed decrease of phosphorylation after treatment of ZYM-201. The same results were shown in vivo experiments. These results suggest that ZYM-201 may play a role in the modulation of inflammatory responses through inhibiting NF-${\kappa}B$ activation and downregulating the expression of costimulatory molecules on B cells.

• IMMUNE NETWORK
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• v.5 no.2
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• pp.68-77
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• 2005

Background: Costimulation is a critical process in Ag-specific immune responses. Both B7.1 and CD28 molecules have been reported to stimulate T cell responses during antigen presentation. Therefore, we tested whether Ag-specific immune responses as well as protective immunity are influenced by coinjecting with B7.1 and CD28 cDNAs in a mouse HSV-2 challenge model system. Methods: ELISA was used to detect levels of antibodies, cytokines and chemokines while thymidine incorporation assay was used to evaluate T cell proliferation levels. Results: Ag-specific antibody responses were enhanced by CD28 coinjection but not by B7.1 coinjection. Furthermore, CD28 coinjection increased IgG1 production to a significant level, as compared to pgD+pcDNA3, suggesting that CD28 drives Th2 type responses. In contrast, B7.1 coinjection showed the opposite, suggesting a Th1 bias. B7.1 coinjection also enhanced Ag-specific Th cell proliferative responses as well as production of Th1 type cytokines and chemokines significantly higher than pgD+pcDNA3. However, CD28 coinjection decreased Ag-specific Th cell proliferative responses as well as production of Th1 types of cytokines and chemokine significantly lower than pgD+pcDNA3. Only MCP-1 production was enhanced by CD28. B7.1 coimmunized animals exhibited an enhanced survival rate as well as decreased herpetic lesion formation, as compared to pgD+pcDNA3. In contrast, CD28 vaccinated animals exhibited decreased survival from lethal challenge. Conclusion: This study shows that B7.1 enhances protective Th1 type cellular immunity against HSV-2 challenge while CD28 drives a more detrimental Th2 type immunity against HSV-2 challenge, supporting an opposite role of B7.1 and CD28 in Ag-specific immune responses to a Th1 vs Th2 type.

• IMMUNE NETWORK
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• v.9 no.3
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• pp.84-89
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• 2009

The main stream of CD137 studies has been directed to the function of CD137 in $CD8^+$ T-cell immunity, including its anti-tumor activity, and paradoxically the immunosuppressive activity of CD137, which proves to be of a great therapeutic potential for animal models of a variety of autoimmune and inflammatory diseases. Recent studies, however, add complexes to the biology of CD137. Accumulating is evidence supporting that there exists a bidirectional signal transduction pathway for the CD137 receptor and its ligand (CD137L). CD137/CD137L interactions are involved in the network of hematopoietic and nonhematopoietic cells in addition to the well characterized antigen-presenting cell-T cell interactions. Signaling through CD137L plays a critical role in the differentiation of myeloid cells and their cellular activities, suggesting that CD137L signals trigger and sustain inflammation. The overall consequence might be that the amplified inflammation by CD137L enhances the T-cell activity together with CD137 signals by upregulating costimulatory molecules, MHC molecules, cell adhesion molecules, cytokines, and chemokines. Solving this outstanding issue is urgent and will have an important clinical implication.

• Biomedical Science Letters
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• v.25 no.4
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• pp.398-406
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• 2019

Cancer immunotherapy using gene-modified tumor cells is safe and customized cancer treatment method. In this study, we made gene-modified tumor cells by transferring costimulatory molecules, 4-1BBL and OX40L, into tumor cells using lentivirus vector, and identified anti-cancer effect of gene-modified tumor cells in CT26 mouse colorectal tumor model. We construct pLVX-puro-4-1BBL, -OX40L vector for lentivirus production and optimized the transfection efficiency and transduction efficiency. The transfection efficiency is maximal at DNA:cationic polymer = 1:0.5 and DNA 2 ㎍ for lentivirus production. Then, the lentiviral including 4-1BBL and OX40L was used to deliver CT26 mouse tumor cells to establish optimal delivery conditions according to the amount of virus. The transduction efficiency is maximal at 500 μL volume of lentiviral stock without change in cell shape or growth rate. CT26-4-1BBL, CT26-OX40L significantly inhibited the tumor growth compare with CT26-WT or CT26-β-gal cell line. These data showed the possibility the use of genetically modified tumor cells with costimulatory molecule as cancer immunotherapy agent.

• Biomolecules & Therapeutics
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• v.16 no.2
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• pp.126-131
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• 2008

Immunosuppressive therapy after organ transplantation is routinely used to prevent rejection of the organ, because this decreases the risk of adverse events, infection, and malignancies. Recently, ursodeoxycholic acid (UDCA), which is isolated from the dried bile of adult Chinese bears, has been shown to reduce the incidence and severity of acute rejection of liver allograft during early phase of liver transplantation. Therefore, in this study, we investigated the effect of UDCA on the proliferation of splenocytes exposed to PMA plus ionomycin. Our results demonstrated that UDCA decreased the splenocytes' proliferation in a dose-dependent manner. The decreased cell proliferation was accompanied with the decreased secretion of cytokines such as IL-2, IFN-${\gamma}$ and TNF-${\alpha}$. In addition, the pretreatment of UDCA on splenocytes stimulated with PMA plus ionomycin decreased the mRNA levels of cytokines (IL-2, IFN-${\gamma}$ and TNF-${\alpha}$) and costimulatory molecules (B7.2 and PD-L1). These results suggest the beneficial effect of UDCA on organ transplantation by decreasing lymphocyte proliferation.

• BMB Reports
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• v.45 no.9
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• pp.538-543
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• 2012

We evaluated the expression of the costimulatory molecules CD80 and CD83 and major histocompatibility (MHC) class II induced by 2,4-dinitrofluorobenzene (DNFB) in the RAW 264.7 macrophage cell line. In contrast to the previously reported effect of DNFB on dendritic cells, CD86 expression did not change. Furthermore, we observed that the CD83 expression level transiently increased and then decreased. Induction of CD80 and MHC class II molecule expression and a decrease in CD83 expression by DNFB in vitro were also confirmed in splenocytes of BALB/c and NC/Nga mice. However, DNFB did not influence CD83 expression in peritoneal $CD11b^+$ cells from BALB/c or NC/Nga mice. Detailed in vivo experiments and further studies on the possible contribution of $CD11b^+$ cells to induce atopic dermatitis (AD) would be helpful to attain a better understanding of AD pathogenesis.

• Journal of Ginseng Research
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• v.41 no.3
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• pp.298-306
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• 2017

Background: Compound K (CK) is a bioactive derivative of ginsenoside Rb1 in Panax ginseng (Korean ginseng). Its biological and pharmacological activities have been studied in various disease conditions, although its immunomodulatory role in innate immunity mediated by monocytes/macrophages has been poorly understood. In this study, we aimed to elucidate the regulatory role of CK on cellular events mediated by monocytes and macrophages in innate immune responses. Methods: The immunomodulatory role of CK was explored by various immunoassays including cell-cell adhesion, fibronectin adhesion, cell migration, phagocytic uptake, costimulatory molecules, reactive oxygen species production, luciferase activity, and by the measurement of mRNA levels of proinflammatory genes. Results: Compound K induced cell cluster formation through cell-cell adhesion, cell migration, and phagocytic activity, but it suppressed cell-tissue interactions in U937 and RAW264.7 cells. Compound K also upregulated the surface expression of the cell adhesion molecule cluster of differentiation (CD) 43 (CD43) and costimulatory molecules CD69, CD80, and CD86, but it downregulated the expression of monocyte differentiation marker CD82 in RAW264.7 cells. Moreover, CK induced the release of reactive oxygen species and induced messenger RNA expression of proinflammatory genes, inducible nitric oxide synthase, and tumor necrosis factor-alpha by enhancing the nuclear translocation and transcriptional activities of nuclear factor kappa-B and activator protein-1. Conclusion: Our results suggest that CK has an immunomodulatory role in innate immune responses through regulating various cellular events mediated by monocytes and macrophages.