• Biomolecules & Therapeutics
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• 제18권4호
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• pp.463-468
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• 2010

T-cell activation depends on signals received by the T-cell receptor and CD28 co-stimulatory receptor. Since B7.1 and B7.2 molecules expressed on the surface of antigen presenting cells provide co-stimulatory signals through CD28 to T-cells, an inhibitor of CD28-B7.1/B7.2 binding has been proposed as a therapeutic agent for suppression of excessive T-cell activity. Although anti-B7.1/B7.2 antibodies are known to block B7.1 and B7.2 molecules, their effects on intracellular events in antigen presenting cells remain unclear. In this study, anti-B7.1/B7.2 antibodies decreased secretion of nitric oxide and pro-inflammatory cytokines such as TNF-$\alpha$, IL-$1{\beta}$, and IL-12 in LPS-activated RAW264.7 macrophage-like cells and peritoneal macrophages. Moreover, anti-B7.1/B7.2 antibodies inhibited $I{\kappa}B{\alpha}$ phosphorylation and down-regulated expression of co-stimulatory molecules including B7.1, B7.2, and PD-L1 in LPS-stimulated peritoneal macrophages. These findings suggest that CTLA4-Ig and anti-B7.1/B7.2 antibodies may be candidates to treat chronic inflammatory diseases and autoimmune responses caused by excessive activation of both T-cells and macrophages.

• IMMUNE NETWORK
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• 제10권3호
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• pp.92-98
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• 2010

Background: Nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used to relieve pain, reduce fever and inhibit inflammation. NSAIDs function mainly through inhibition of cyclooxygenase (COX). Growing evidence suggests that NSAIDs also have immunomodulatory effects on T and B cells. Here we examined the effects of NSAIDs on the antigen presenting function of dendritic cells (DCs). Methods: DCs were cultured in the presence of aspirin or ibuprofen, and then allowed to phagocytose biodegradable microspheres containing ovalbumin (OVA). After washing and fixing, the efficacy of OVA peptide presentation by DCs was evaluated using OVA-specific CD8 and CD4 T cells. Results: Aspirin and ibuprofen at high concentrations inhibited both MHC class I and class II-restricted presentation of OVA in DCs. In addition, the DCs generated in the presence of low concentrations of the drugs exhibit a profoundly suppressed capability to present MHC-restricted antigens. Aspirin and ibuprofen did not inhibit the phagocytic activity of DCs, the expression level of total MHC molecules and co-stimulatory molecules on DCs. Ibuprofen rather increased the expression level of total MHC molecules and co-stimulatory molecules on DCs. Conclusion: These results demonstrate that aspirin and ibuprofen inhibit the intracellular processing event of the phagocytosed antigen, and further suggest that prolonged administration of NSAIDs in high doses may impair the capability of DCs to present antigens in asiociation with MHC molecules.

• Parasites, Hosts and Diseases
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• 제61권2호
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• pp.138-146
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• 2023

Toxoplasma gondii is an intracellular protozoan parasite which can infect most warm-blooded animals and humans. Among the different mouse models, C57BL/6 mice are more susceptible to T. gondii infection compared to BALB/c mice, and this increased susceptibility has been attributed to various factors, including T-cell responses. Dendritic cells (DCs) are the most prominent type of antigen-presenting cells and regulate the host immune response, including the response of T-cells. However, differences in the DC responses of these mouse strains to T. gondii infection have yet to be characterized. In this study, we cultured bone marrow-derived DCs (BMDCs) from BALB/c and C57BL/6 mice. These cells were infected with T. gondii. The activation of the BMDCs was assessed based on the expression of cell surface markers and cytokines. In the BMDCs of both mouse strains, we detected significant increases in the expression of cell surface T-cell co-stimulatory molecules (major histocompatibility complex (MHC) II, CD40, CD80, and CD86) and cytokines (tumor necrosis factor (TNF)-α, interferon (IFN)-γ, interleukin (IL)-12p40, IL-1β, and IL-10) from 3 h post-T. gondii infection. The expression of MHC II, CD40, CD80, CD86, IFN-γ, IL-12p40, and IL-1β was significantly higher in the T. gondii-infected BMDCs obtained from the C57BL/6 mice than in those from the BALB/c mice. These findings indicate that differences in the activation status of the BMDCs in the BALB/c and C57BL/6 mice may account for their differential susceptibility to T. gondii.

• Biomolecules & Therapeutics
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• 제21권1호
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• pp.35-41
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• 2013

Metformin is widely used for T2D therapy but its cellular mechanism of action is undefined. Recent studies on the mechanism of metformin in T2D have demonstrated involvement of the immune system. Current immunotherapies focus on the potential of immunomodulatory strategies for the treatment of T2D. In this study, we examined the effects of metformin on the antigen-presenting function of antigen-presenting cells (APCs). Metformin decreased both MHC class I and class II-restricted presentation of OVA and suppressed the expression of both MHC molecules and co-stimulatory factors such as CD54, CD80, and CD86 in DCs, but did not affect the phagocytic activity toward exogenous OVA. The class II-restricted OVA presentation-regulating activity of metformin was also confirmed using mice that had been injected with metformin followed by soluble OVA. These results provide an understanding of the mechanisms of the T cell response-regulating activity of metformin through the inhibition of MHC-restricted antigen presentation in relation to its actions on APCs.

• 약학회지
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• 제51권6호
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• pp.482-489
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• 2007

Kaempferitrin, isolated from Kenaf (Hibiscus cannabinus), was examined to evaluate its modulatory effects on antigen-presenting cell functions of macrophages/monocytes such as phagocytosis of foreign materials, up-regulation of costimulatory molecules (CD40, CD80 and CD86), adhesion molecule activation, and antigen processing and presentation. Kaempferitrin strongly blocked up-regulation of CD40, CD80 and CD86, but not pattern recognition receptor (PRR) (e.g., TLR2). It also suppressed functional activation of CD29 (${\beta}1$-integrins), as assessed by cell-cell adhesion assay, required for T cell-antigen-presenting cell (APC) interaction. Furthermore, this compound did not block a simple activation of CD29, as assessed by cell-fibronectin adhesion assay. However, the compound did not diminish phagocytic uptake, an initial step for antigen processing, and ROS generation in RAW264.7 cells. In particular, to understand molecular mechanism of kaempferitrin-mediated inhibition, the regulatory role of LPS-induced signaling events was examined using immunoblotting analysis. Interestingly, this compound dose dependently suppressed the phosphorylation of $I{\kappa}B{\alpha}$, Src, Akt and Syk, demonstrating that it can negatively modulate the activation of these signaling enzymes. Therefore, our data suggested that kaempferitrin may be involved in regulating APC function-relevant immune responses of macrophages and monocytes by regulating intracellular signaling.

• IMMUNE NETWORK
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• 제3권3호
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• pp.248-254
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• 2003

Oral administration of antigen has long been used in the induction of immune tolerance in various animal models of autoimmune diseases including rheumatoid arthritis (RA). Alleveation of arthritogenic symptoms has been reported from RA patients who received oral administration of type II collagen (CII) without side effects, however its rather inconsistent therapeutic efficacy and variation among patients calls for more detailed investigation on the mechanism of oral tolerance to be settled as regular treatment for RA. In an attempt to understand the immunogenic processes underpinning tolerance induction by orally administered CII, we analyzed changes in the expression of costimulatory molecules and STAT/SOCS signaling messengers in the mouse model of collagen induced arthritis (CIA). We found thatin the spleen of CIA mice, that has been undergone repeated oral feeding of CII prior to the induction of arthritis, showed increased promortion of CTLA4 expressing lymphocytes than in the spleen of PBS fed control. On the other hand, cells expressing CD28 or ICOS were decreased in the spleen of tolerized mice. Tolerance induction by oral CII administration also enhanced the expression of STAT6 in both RNA and protein level, while not affecting the expression of STAT3. The expression of SOCS3, which hasbeen known to transmit STAT-mediated signals from Th2 type cytokines, remained unchanged in the spleen of tolerized mice. Interestingly transcript of SOCS1, which has been associated with Th1 related pathways, was only visible in the spleen of tolerized but not of control mice, suggesting that as in the case of IL-6 signaling, it may exert a feed back inhibition toward the Th1 type stimulation.

• IMMUNE NETWORK
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• 제10권2호
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• pp.55-63
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• 2010

Background: Cordyceps militaris has been used in traditional medicine to treat numerous diseases and has been reported to possess both antitumor and immunomodulatory activities in vitro and in vivo. However, the pharmacological and biochemical mechanisms of Cordyceps militaris extract (CME) on macrophages have not been clearly elucidated. In the present study, we examined how CME induces the production of proinflammatory cytokines, transcription factor, and the expression of co-stimulatory molecules. Methods: We confirmed the mRNA and protein levels of proinflammatory cytokines through RT-PCR and western blot analysis, followed by a FACS analysis for surface molecules. Results: CME dose dependently increased the production of NO and proinflammatory cytokines such as IL-$1{\beta}$, IL-6, TNF-${\alpha}$, and $PGE_2$, and it induced the protein levels of iNOS, COX-2, and proinflammatory cytokines in a concentrationdependent manner, as determined by western blot and RT-PCR analysis, respectively. The expression of co-stimulatory molecules such as ICAM-1, B7-1, and B7-2 was also enhanced by CME. Furthermore, the activation of the nuclear transcription factor, NF-${\kappa}B$ in macrophages was stimulated by CME. Conclusion: Based on these observations, CME increased proinflammatory cytokines through the activation of NF-${\kappa}B$, further suggesting that CME may prove useful as an immune-enhancing agent in the treatment of immunological disease.

• IMMUNE NETWORK
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• 제11권6호
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• pp.390-398
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• 2011

Background: Epstein Barr virus (EBV) infected B cells are transformed into lymphoblastoid cell lines. Some researchers suggested some a few similarities between this process and carcinogenesis. We observed the expression of CD80 and CD86, co-stimulatory molecules on EBV-transformed B cells and changes of CD54 expression after stimulation of CD80 and CD86. Methods: CD80 and CD86 were stimulated using anti-CD80 and anti-CD86 monoclonal antibodies. To assess apoptosis and surface protein expression, flow cytometric analysis was performed. Intracellular signal molecules were evaluated by RT-PCR and immunoblot. Morphology and localization of proteins were examined using inverted or confocal microscope. Results: Cross-linking of CD80 and CD86 induced apoptosis and interfered with proliferation of EBV-transformed B cells, and dispersion of clumped cells. We also examined that their stimulation induced ROS accumulation and reduced CD54 expression. Interestingly, we observed that CD80 and CD86 diminished the expression of CD54 in different methods. Both CD80 and CD86 downregulated activation of focal adhesion kinase. CD80 stimulus inhibited CD54 expression through mainly RhoA inactivation, while CD86 down-regulated Ras and JNK phosphorylation. Conclusion: These results suggest that co-stimulatory CD80 and CD86 molecules, expressed EBV-transformed B cells, may play a role in apoptosis and cell adhesion.

• IMMUNE NETWORK
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• 제14권6호
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• pp.328-332
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• 2014

Dexamethasone (Dex) was shown to inhibit the differentiation, maturation, and antigen-presenting function of dendritic cells (DC) when added during DC generation or maturation stages. Here, we examined the direct effects of Dex on MHC-restricted antigen processing. Macrophages were incubated with microencapsulated ovalbumin (OVA) in the presence of different concentrations of Dex for 2 h, and the efficacy of OVA peptide presentation was evaluated using OVA-specific CD8 and CD4 T cells. Dex inhibited both class I- and class II-restricted presentation of OVA to T cells; this inhibitory effect on antigen presentation was much more potent in immature macrophages than in mature macrophages. The presentation of the exogenously added OVA peptide SIINFEKL was not blocked by Dex. In addition, short-term treatment of macrophages with Dex had no discernible effects on the phagocytic activity, total expression levels of MHC molecules or co-stimulatory molecules. These results demonstrate that Dex inhibits intracellular processing events of phagocytosed antigens in macrophages.

• 융합정보논문지
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• 제10권6호
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• pp.164-176
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• 2020

인체 적응 면역 반응을 일으키는데 중요한 항원 특이적 T 세포를 활용한 면역 세포 치료에서 T 세포를 체외에서 배양하고 클론 확장시키는 과정은 매우 섬세하고 복잡하여 조절하기가 쉽지 않아 T 세포의 활성화와 클론 확장을 유도하면서도 조절 및 취급이 용이한 인공 항원제시세포 개발의 필요성이 대두되고 있다. 인공 항원제시세포는 인체의 항원제시세포의 세포 표면 분자와 작용을 모방하게 되는데, 기본적인 신호 분자인 MHC-항원 복합체, 공동 자극 분자, 그리고 용해성 면역 조절 분자를 필수적으로 발현하여야 한다. 또한 T 세포가 항원과 접촉할 때, 이들 분자들이 잘 조직화되어 작용하는 것이 효과적인 T 세포 활성화에 중요하다. 본 논문에서는 여러 인공 항원제시세포 제작 방법과 세포 표면 분자들의 결합 방법과 물리적인 특성이 T 세포와의 상호작용에 중요함을 고찰하였으며, 효과적인 T 세포 활성화를 유도하며 면역세포치료에 적용 가능한 인공항원제세세포의 제작 방법을 살펴보았다.