• Korean Journal of Medicinal Crop Science
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• v.17 no.2
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• pp.133-138
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• 2009

Nelumbo nucifera (lotus) is known to be a useful medicinal plant and leaf extract contains several flavonoids and alkaloids. To analyze the effect of Nelumbo nucifera leaves extract (NNL) on the HBsAg production, we treated NNL on HepG2.2.15 cells which contain the hepatitis B viral genome and secrete surface antigen into media. NNL suppressed the production of hepatitis B surface antigen as a dose-dependent manner. To analyze the effect of NNL on HBV DNA replication, PCR analysis was performed. NNL was not affected the HBV DNA replication and HBsAg mRNA expression. To understand the effect of NNL on the production of HBsAg, we carried out the analysis of lipid-metabolizing gene expression using one-step RT-PCR. NNL reduced the gene expression of FASN and SREBP2 and increased the expression of LDLR. Triglyceride content of HepG2.2.15 cells was not decreased by treatment of NNL. This result suggests a possibility that NNL may have an effect for the inhibition of hepatitis B surface antigen by modulation of lipid and cholesterol metabolism.

• Journal of Life Science
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• v.15 no.3 s.70
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• pp.492-498
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• 2005

The mechanism of activation of phospholipase D2 (PLD2) remains undefined although mechanisms have been described for the activation of PLDI. By expression of mutated forms of haemaglutinnin-tagged PLD2 in a mast cell (RBL-2H3) line, we show that PLD2 is phosphorylated at tyrosines -11, -14, and -470 and that tyrosine-470 is critical for activation of PLD2 by antigen. Studies were performed with mutated-DNA constructs for haemaglutinnin-tagged PLD2 in which codons for tyrosine -11, -14, -165, and -470 were mutated to phenylalanine either individually or collectively. Transient expression of these constructs showed that mutation of tyrosine -11, -14, -470, or all tyrosines (all-mutated PLD2) suppressed antigen-induced tyrosine phosphorylation of PLD2 but only the tyrosine-470 mutant failed to be activated by antigen as assessed by in vitro assay of immunoprepitated PLD2 or by assay of PLD in intact cells. The critical role of tyrosine-470 was confirmed in studies with add-back mutants (phenylalanine back to tyrosine) of the all-mutated PLD. The findings provide the first description of a mechanism of activation of PLD2 in a physiological setting.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.8
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• pp.3627-3630
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• 2012

The epithelial cell adhesion molecule (EpCAM) is a pan-epithelial differentiation antigen that is expressed on almost all carcinomas. However, a role in rat liver carcinogenesis has never been reported previously. Thus, its expression was investigated herein in rat liver tumors induced by diethylnitrosamine (DEN). Twenty male 5-week-old F344 rats were used in this experiment. Mini-osmotic pumps containing doses of 47.5 mg of DEN were inserted into the abdominal cavity of each animal to initiate liver carcinogenesis. All animals were sacrificed at 26 weeks after DEN treatment. At necropsy, hepatic masses were processed for histopathological examination, which revealed forty-four hepatocellular adenomas (HCAs) and twenty hepatocellular carcinomas (HCC). Tumors were immunohistochemically analyzed for EpCAM, proliferating cell nuclear antigen (PCNA) and co-localization of the two. EpCAM expression was mainly detected in hepatic tumor cells, showing a cytoplasmic staining pattern. However, expression was also slightly observed in normally-appearing surrounding hepatic cells. PCNA expression was highly detected in tumor cells, showing nuclear staining. Double staining of EpCAM and PCNA in tumors showed many cells with co-localization. Taken together, EpCAM and PCNA expression were increased in DEN-induced tumors and many tumor cells showed co-expression. It is suggested that EpCAM may increase during DEN-induced tumors, possibly associated with cell proliferation.

• IMMUNE NETWORK
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• v.2 no.1
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• pp.35-40
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• 2002

Background: CTLA-4 (Cytotoxic T Lymphocyte associated Antigen 4, CD152) has been known as a homologue of CD28, an accessory molecule providing a key costimulatory signal for successful antigen-driven activations of T lymphocyte. Most of biochemical and cell biological characteristics of the CD152 protein remain unknown while those of CD28 have been characterized in detail. Methods: In this study CD152 expression in both $CD4^+$ and $CD8^+$ PBLs was studied by using flow cytometry. And intracellular CD152 multiprotein complex was purified and used for generating antibodies recognizing proteins composing of intracellular CTLA-4 multi protein complex. Results: Level of surface expression of this molecule was peaked at 2 days of PHA stimulation in flow cytometric analysis. 40~45% of PHA blast cells were $CD152^+$ in both of two subsets at this stage and the level of expression were equivalent in both two subsets. Contrary to this surface expression, intracellular expression was peaked at day 3 and it was preferentially induced in $CD8^+$ cells and about 60% of $CD8^+$ cells were $CD152^+$ at this stage. High molecular weight (>350 kD) intacellular CD152 protein complex purified by using preparative electrophoresis were immunized into rabbits and then 3 different anti-P34PC4, anti-P34PC7 and anti-P34PC8 antibodies were obtained. Using these 3 antibodies two unknown antigens associated with intracellular CD152 multiprotein complex were found and their molecular weights were 54 kD and 75 kD, respectively. Among these, the former was present as 110 kD homodimer in non-reducing condition. Conclusion: It seemed that 34 kD intracellular CD152 molecule forms high molecular weight multiprotein complex at least with 2 proteins of 75 kD monomer and 110 kD homodimer.

• IMMUNE NETWORK
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• v.14 no.6
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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.

• IMMUNE NETWORK
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• v.5 no.3
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• pp.150-156
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• 2005

Background: Dendritic cells (DCs) playa critical role not only in the initiation of immune responses, but also in the induction of immune tolerance. In an effort to regulate immune responses through the modulation of antigen presenting cell (APC) function of DCs, we searched for and characterized APC function modulators from natural products. Methods: DCs were cultured in the presence of propolis components, WP and CP, and then examined for their ability to present exogenous antigen in association with major histocompatibility complexes (MHC). Results: WP and CP inhibited class I MHC-restricted presentation of exogenous antigen (cross-presentation) in a DC cell line, DC2.4 cells, and DCs generated from bone marrow cells with GM-CSF and IL-4. The inhibitory activity of WP and CP appeared to be due not only to inhibition of phagocytic activity of DCs, but also to suppression of expression of MHC molecules on DCs. We also examined the effects of WP and CP on T cells. Interestingly, WP and CP increased IL-2 production from T cells. Conclusion: These results demonstrate that WP and CP inhibit MHC-restricted presentation of exogenous antigen through down-regulation of phagocytic activity and suppression of expression of MHC molecules on DCs.

• IMMUNE NETWORK
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• v.10 no.4
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• pp.135-143
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• 2010

Background: Cordyceps militarys water extract (CME) has been reported to exert antitumor and immunomodulatory activities in vivo and in vitro. However, the therapeutic mechanism has not yet been elucidated. In this study, we examined the effects of CME on the antigen presenting function of antigen presenting cells (APCs). Methods: Dendritic cells (DCs) were cultured in the presence of CME, and then allowed to phagocytose microspheres containing ovalbumin (OVA). After washing and fixing the efficacy of OVA, peptide presentation by DCs were evaluated using CD8 and CD4 T cells. Also, we confirmed the protein levels of proinflammatory cytokines through western blot analysis. Results: CME enhanced both MHC class I and class II-restricted presentation of OVA in DCs. In addition, the expression of both MHC class I and II molecules was enhanced, but there was no changes in the phagocytic activity of exogenous OVA. Furthermore, CME induced the protein levels of iNOS, COX-2, proinflammatory cytokines, and nuclear p65 in a concentration-dependent manner, as determined by western blot. Conclusion: These results provide an understanding of the mechanism of the immuno-enhancing activity of CME on the induction of MHC-restricted antigen presentation in relation to their actions on APCs.

• Korean Journal of Veterinary Service
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• v.45 no.4
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• pp.269-275
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• 2022

Blood type in dogs is based on the antigen present on the red blood cell surface. Dog erythrocyte antigen 1 is a crucial red blood cell antigen in dogs, whereas the dog erythrocyte antigen 7 has been studied in limited dog breeds worldwide. To assess the prevalence of dog erythrocyte antigens 1 and 7 in 11 breeds in the Republic of Korea, 624 dog blood samples were examined for antigen detection. Overall, 520 dogs (83.3%) showed dog erythrocyte antigen 1 expression. The distribution varied from 50.0~100.0% according to the breed. Dog erythrocyte antigen 1-positive blood type was the highest in Chihuahua (100%), followed by Jindo dog (98.5%), and Sapsaree (95.3%). Dog erythrocyte antigen 7 was positive in 125 dogs (20.0%), and the positivity varied from 5.0~42.9% according to the breed. Dog erythrocyte antigen 7-positive blood type was the highest in Beagle (42.9%), followed by Chihuahua (37.5%), and Jindo dog (27.8%). The high prevalence of dog erythrocyte antigen 1 is because of the high proportion of Jindo dog and Sapsaree breeds that were mostly positive for the antigen. The high abundance of these breeds could be due to inbreeding and local breeding in the Republic of Korea. To our best knowledge, this study is the first to report on the prevalence of dog erythrocyte antigens 1 and 7 among various canine breeds in the Republic of Korea. The prevalence data obtained from this study may contribute to baseline information on veterinary transfusion medicine in small animal practice.

• The Journal of Korean Society of Virology
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• v.26 no.1
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• pp.77-90
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• 1996

Nucleocapsid protein (NP)which exists in the particle of hantavirus and surrounds the viral RNA genome is one of the major structural proteins and plays role of antigen to elicit the antibody detected predorminantly right after infection of the virus in the patients of hemorragic fever with renal syndrome (HFRS)or experimental animals. NP is important target antigen in serological diagnostic system of HFRS utilizing whole antigens from the native virus particle, such as IFA, ELISA and Western blotting. Therefore, the preparation of this protein in the level of higher quantity and purity is desirasble for developed dianosis of the disease. The purpose of this study is the cloning of NP gene which exists in the S genome segment of Maaji (MAA) virus and expression of the gene to obtain qualified, genetically engineered NP to be utilized as an immunodiagnostic antigen. First of all, for the purpose of amplifing the MAA-NP gene by PCR, the specific primers were built from the known nucleotide sequence of Hantaan viral NP gene. The viral cDNA of the NP gene was synthesized by using the primers and RNase $H^-$ AMV reverse transcriptase. Thereafter, using this cDNA as a template, the NP gene was amplified specifically by Taq DNA polymrerase. The pT7blue (R)T-overhang vector systems were used for cloning of the amplified NP gene. The expression system was consisted of BL21 (DE3)pLysS and pET16b as a host and a plasmid repectively. Into Ndel site of pET16b, NP gene was ligated with cohesive end for the expression. Insertion of NP gene in the plasmid was confirmed by PCR and mini prep methods. For expression, IPTG was used and the expressed protein was characterized by Western blotting. The MAA-NP was expressed as the form of inclusion body (insoluble fraction)and the protein purified by affinity and metal chealating columns reacted specifically with the sera from patients of HFRS as to be tested by ELISA and Western blotting.

• IMMUNE NETWORK
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• v.2 no.1
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• pp.53-59
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• 2002

Background: Clinical observations and laboratory studies have supported an immune basis for most acquired aplastic anemias, with the majority of patients responding to immunosuppressive therapy. Fas, a member of the tumor necrosis factor (TNF) receptor superfamily is a critical downregulator of cellular immune responses. Proinflammatory cytokines like interferon gamma (IFN-${\gamma}$) and TNF-${\alpha}$ can induce Fas expression and render hematopoietic progenitor cells susceptible to Fas-induced growth suppression and apoptosis. Methods: In order to investigate the involvement of apoptosis in the pathogenesis of aplastic anemia (AA), we measured the expression of Fas antigen and caspase-3 on bone marrow (BM) mononuclear cells (MNCs) of AA in the presence or absence of IFN-${\gamma}$, TNF-${\alpha}$, or macrophage inflammatory protein 1-${\alpha}$ (MIP-$1{\alpha}$). Results: We confirmed that AA BM MNCs were more apoptotic and highly expressed Fas antigen than normal donors. Stimulation by IFN-${\gamma}$, TNF-${\alpha}$, or MIP-$1{\alpha}$ increased Fas antigen and caspase-3 expression in AA BM MNCs than BM MNCs of normal donors. Anti-Fas monoclonal antibody enhanced IFN-${\gamma}$, TNF-${\alpha}$, or MIP$1{\alpha}$ mediated caspase-3 expression in BM MNCs of normal donors. Among these three cytokines, IFN-${\gamma}$ enhanced apoptosis most strongly via Fas-caspase-3 pathway. Conclusion: These results suggest that Fas signal pathway may play a role in the pathophysiology of aplastic anemia and negative hematopoietic regulators like IFN-${\gamma}$ can induce apoptosis of bone marrow progenitors in part by Fas induction.