• Asian-Australasian Journal of Animal Sciences
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• v.18 no.4
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• pp.497-501
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• 2005

An experiment was conducted on crossbred male calves to study the effect of arsenic (As) on immunity status and certain hematological parameters. Ten crossbred male calves of 3-4 months of age were distributed into two equal groups. Group I was kept as control, whereas, group II was supplemented daily with 50 ppm As (as $As_sO_3$) up to 90 days, in the diet. Calves of both groups were fed as per ICAR standards and their requirements were fulfilled by feeding concentrate mixture and green oats. All calves were kept under similar managemental conditions. Blood samples were collected at fortnightly intervals to estimate various haematological parameters and superoxide dismutase (SOD) enzyme activity. Serum Ig and serum glutamic pyruvate transaminase (SGPT) were also measured. Cell-mediated immune responses of the calves were monitored at 0, 45 and 90 of experimental feeding, through lymphocyte proliferation. No change in blood total leukocyte counts (TLC), differential leukocyte counts (DLC), packed cell volume (PCV), haemoglobin (Hb) and SGPT was observed with As supplementation. A decrease in SOD activity was noticed in group II calves. Stimulation index (SI) for lymphocyte proliferation decreased from 1.14 to 0.79 in group II calves during 90 days experimental feeding, whereas, there was no change in SI values in group I indicating significant decrease in immune response of As supplemented calves. Blood As concentration increased in group II calves with the decrease in immune response. Short term supplementation of As to growing calves suggested suppressive effects on cell-mediated immunity. However, long term experiments are required to demonstrate clearly the efects of this toxic metal in calves.

• Toxicological Research
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• v.31 no.1
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• pp.11-16
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• 2015

Our body's immune system has defense mechanisms against pathogens such as viruses and bacteria. Immune responses are primarily initiated by the activation of toll-like receptors (TLRs). In particular, TLR4 is well-characterized and is known to be activated by gram-negative bacteria and tissue damage signals. TLR4 requires myeloid differentiation factor 2 (MD2) as a co-receptor to recognize its ligand, lipopolysaccharides (LPS), which is an extracellular membrane component of gram-negative bacteria. Gambogic acid is a xanthonoid isolated from brownish or orange resin extracted from Garcinia hanburyi. Its primary effect is tumor suppression. Since inflammatory responses are related to the development of cancer, we hypothesized that gambogic acid may regulate TLR4 activation. Our results demonstrated that gambogic acid decreased the expression of pro-inflammatory cytokines ($TNF-{\alpha}$, IL-6, IL-12, and $IL-1{\beta}$) in both mRNA and protein levels in bone marrow-derived primary macrophages after stimulation with LPS. Gambogic acid did not inhibit the activation of Interferon regulatory factor 3 (IRF3) induced by TBK1 overexpression in a luciferase reporter gene assay using IFN-${\beta}$-PRD III-I-luc. An in vitro kinase assay using recombinant TBK1 revealed that gambogic acid did not directly inhibit TBK1 kinase activity, and instead suppressed the binding of LPS to MD2, as determined by an in vitro binding assay and confocal microscopy analysis. Together, our results demonstrate that gambogic acid disrupts LPS interaction with the TLR4/MD2 complex, the novel mechanism by which it suppresses TLR4 activation.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.48 no.3
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• pp.346-353
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• 2015

Glucocorticoids (GCs) are steroid hormones regulated through responses to stress to maintain diverse metabolic and homeostatic functions. GCs act on the glucocorticoid receptor (GR), a member of the nuclear receptor family. This study identified and characterized the GR gene from the big-belly seahorse Hippocampus abdominalis designating it HaGR. The open reading frame of the HaGR cDNA was 2,346 bp in length, encoding a 782-amino-acid polypeptide with a theoretical isoelectric point of 6.26 and predicted molecular mass of 86.8 kDa. Nuclear receptors share a common structural organization, comprising an N-terminal transactivation domain, DNA-binding domain, and C-terminal ligand-binding domain. The tissue-specific mRNA expression profile of HaGR was analyzed in healthy seahorses using a qPCR technique. HaGR mRNA was expressed ubiquitously in all of the tissues examined, with the highest expression levels in kidney, intestine, stomach, and gill tissues. The mRNA expression in response to immune challenge with lipopolysaccharide (LPS), polyinosinic:polycytidylic acid (poly I:C), Edwardsiella tarda, and Streptococcus iniae revealed that it is inducible in response to pathogen infection. These results suggest that HaGR is involved in the immune response of the big-belly seahorse.

• Journal of the Korean Dietetic Association
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• v.12 no.1
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• pp.82-88
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• 2006

This study was performed to evaluate the effect of Sorghum bicolor L. Moench(Sorghum, su-su) extracts on mouse immune cell activation. As ex vivo experiment, different concentrations(0, 50, 500mg/kg B.W.) of Sorghum bicolor L. Moench water extracts were orally administrated into mouse every other day for four weeks. The proliferation of mouse splenocytes, the number of plaque forming cells(PFC) and the cytokine IL-1β production by activated macrophage were used as indices for immunocompetence. Splenocyte proliferation was enhanced in mouse orally administrated with 50mg/kg B.W./day concentration compared to that of control group. Especially, the highest proliferation of spleoncyte was seen in the mouse orally administrated at the concentration of 50mg/kg B.W./day. The number of plaque forming cells(PFC) to SRBC were significantly enhanced when compared with control group. Also, the mouse of Sorghum bicolor L. Moench water extracts 50mg/kg B.W./day supplementation group with LPS stimulation enhanced level of IL-1$\beta$ cytokine production. This study suggest that supplementation of Sorghum bicolor L. Moench water extracts may enhance the immune function by regulating the splenocytes proliferation, increasing the number of PFC and enhancing the cytokine production by activated macrophage.

• Molecules and Cells
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• v.20 no.2
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• pp.288-296
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• 2005

Cytokines interleukin (IL) 12 and 23 play critical roles in linking innate and adaptive immune responses. They are members of heterodimeric cytokines, sharing a subunit p40. Although IL12/23 p40 is mainly induced in macrophages and dendritic cells (DCs) after stimulation with microbial Toll-like receptor ligands, methods to monitor the cells that produce IL12/23 p40 in vivo are limited. Recently, the mouse model to track p40-expressing cells with fluorescent reporter, yellow fluorescent protein, has been developed. Macrophages and DCs from these mice faithfully reported p40 induction using the fluorescent marker. Here we took advantage of these reporter mice to screen bio-compounds for p40-inducing activity. After screening hundreds of compounds, we found several extracts inducing IL12/23 p40 gene expression. Treatment of DCs with these extracts induced the expression of MHC class II and co-stimulatory molecules, which implies that these might be useful as adjuvants. Next, the in vivo target immune cells of candidate compounds were examined. The reporter system can be useful to identify cells producing IL12 or IL23 in vivo as well as in vitro. Thus, our cytokine reporter system proved to be a valuable reagent for screening for immunostimulatory molecules and identification of target cells in vivo.

• IMMUNE NETWORK
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• v.11 no.2
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• pp.123-133
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• 2011

Background: Mycobacterium tuberculosis (Mtb) heparin binding hemagglutinin (HBHA) is an Ag known to evoke effective host immune responses during tuberculosis infection. However, the molecular basis of the host immune response to HBHA has not been fully characterized. In this study, we examined the molecular mechanisms by which HBHA can induce the expression of proinflammatory cytokines in macrophages. Methods: HBHA-induced mRNA and protein levels of proinflammatory cytokines were determined in bone marrow-derived macrophages (BMDMs) using RT-PCR and ELISA analysis. The roles of intracellular signaling pathways for NF-${\kappa}B$, PI3-K/Akt, and MAPKs were investigated in macrophage proinflammatory responses after stimulation with HBHA. Results: HBHA robustly activated the expression of mRNA and protein of both TNF-${\alpha}$ and IL-6, and induced phosphorylation of NF-${\kappa}B$, Akt, and MAPKs in BMDMs. Both TNF-${\alpha}$ and IL-6 production by HBHA was regulated by the NF-${\kappa}B$, PI3-K, and MAPK pathways. Furthermore, PI3-K activity was required for the HBHA-induced activation of ERK1/2 and p38 MAPK, but not JNK, pathways. Conclusion: These data suggest that mycobacterial HBHA significantly induces proinflammatory responses through crosstalk between the PI3-K and MAPK pathways in macrophages.

• Molecules and Cells
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• v.43 no.3
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• pp.251-263
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• 2020

Flagellin, a major structural protein of the flagellum found in all motile bacteria, activates the TLR5- or NLRC4 inflammasome-dependent signaling pathway to induce innate immune responses. Flagellin can also serve as a specific antigen for the adaptive immune system and stimulate anti-flagellin antibody responses. Failure to recognize commensal-derived flagellin in TLR5-deficient mice leads to the reduction in anti-flagellin IgA antibodies at steady state and causes microbial dysbiosis and mucosal barrier breach by flagellated bacteria to promote chronic intestinal inflammation. Despite the important role of anti-flagellin antibodies in maintaining the intestinal homeostasis, regulatory mechanisms underlying the flagellin-specific antibody responses are not well understood. In this study, we show that flagellin induces interferon-β (IFN-β) production and subsequently activates type I IFN receptor signaling in a TLR5- and MyD88-dependent manner in vitro and in vivo. Internalization of TLR5 from the plasma membrane to the acidic environment of endolysosomes was required for the production of IFN-β, but not for other pro-inflammatory cytokines. In addition, we found that anti-flagellin IgG2c and IgA responses were severely impaired in interferon-alpha receptor 1 (IFNAR1)-deficient mice, suggesting that IFN-β produced by the flagellin stimulation regulates anti-flagellin antibody class switching. Our findings shed a new light on the regulation of flagellin-mediated immune activation and may help find new strategies to promote the intestinal health and develop mucosal vaccines.

• Journal of Physiology & Pathology in Korean Medicine
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• v.20 no.5
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• pp.1249-1253
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• 2006

The fractions of Capsosiphon fulvescens were studied to verify the anticancer and immunostimulating activity. The fractions from the ethanol extract of C. fulvescens were prepared by the systematic extraction procedure with the solvents such as hexane, ethyl ether, methanol, butanol and H$_2$O. The cytotoxic effects of C. fulvescens fractions against human leukemia cell line U937, mouse neuroblastoma cell line (NB41A3), human hepatoma cell line (HepG2)and rat glioma cell line (C6) were investigated. Ethyl ether fraction of C. fulvescens showed the highest cytotoxicity against all four cell lines tested. In addition, H$_2$O fraction also showed relatively high cytotoxicity. Dose dependent patterns were observed on all four cell lines. The immune-stimulating effects of C. fulvescens fractions on rat macrophage cell line (RAW 264.7) were also investigated. All five fractions of C. fulvescens extract stimulated NO production with concentration dependant manner. These results suggest that C. fulvescens may be a useful candidate for a natural antitumor and immune-stimulating agent.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.4
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• pp.389-397
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• 2020

Microglial cells function as major immune cells in the brain, playing an important role in the protection and damage of neurons. BV2 microglia, activated by drug stimulation, secrete inflammatory cytokines by activating the nuclear factor kappa-light-chain-enhancer of the activated B cells pathway and are involved in neuroinflammatory and immune responses. The overactivation of microglia by stimuli can cause neuronal damage, leading to brain disease. Noni, a natural product, reduces the activity of microglia to prevent neuronal damage and is a potential natural medicine because it exerts excellent regeneration and anti-inflammatory effects on damaged cells. In this study, when noni was used to treat BV2 cells stimulated by the anti-cancer drug doxorubicin, it reduced the release of pro-inflammatory cytokines from BV2. On the other hand, neuronal damage is a side effect of doxorubicin. Therefore, the cytokines released from doxorubicin-stimulated BV2 cells treated with noni had a positive effect on the neuronal viability compared to those released from doxorubicin-stimulated BV2 cells not treated with Noni. Thus, Noni increases neuronal viability. These results suggest that noni inhibits the release of cytokines by regulating the nuclear factor kappa-light-chain-enhancer of the activated B cells pathway of BV2, thereby inhibiting neuronal damage.

• IMMUNE NETWORK
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• v.20 no.5
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• pp.38.1-38.12
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• 2020

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that initiate both T-cell responses and tolerance. Tolerogenic DCs (tDCs) are regulatory DCs that suppress immune responses through the induction of T-cell anergy and Tregs. Because lactoferrin (LF) was demonstrated to induce functional Tregs and has a protective effect against inflammatory bowel disease, we explored the tolerogenic effects of LF on mouse bone marrow-derived DCs (BMDCs). The expression of CD80/86 and MHC class II was diminished in LF-treated BMDCs (LF-BMDCs). LF facilitated BMDCs to suppress proliferation and elevate Foxp3⁺ induced Treg (iTreg) differentiation in ovalbumin-specific CD4⁺ T-cell culture. Foxp3 expression was further increased by blockade of the B7 molecule using CTLA4-Ig but was diminished by additional CD28 stimulation using anti-CD28 Ab. On the other hand, the levels of arginase-1 and indoleamine 2,3-dioxygenase-1 (known as key T-cell suppressive molecules) were increased in LF-BMDCs. Consistently, the suppressive activity of LF-BMDCs was partially restored by inhibitors of these molecules. Collectively, these results suggest that LF effectively causes DCs to be tolerogenic by both the suppression of T-cell proliferation and enhancement of iTreg differentiation. This tolerogenic effect of LF is due to the reduction of costimulatory molecules and enhancement of suppressive molecules.