Wen-Bin Chung

National Pingtung University of Science and Technology, P’ing-tung-chieh, Taiwan, Taiwan

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Publications (9)19.77 Total impact

  • Molecular Immunology. 05/2012; 51(1):22.
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    ABSTRACT: Dectin-1, a specific pattern recognition receptor for β-1,3/β-1,6-glucans, is expressed mainly on phagocytes. Human dectin-1 (hDectin-1) and mouse dectin-1 (mDectin-1) were separately expressed on HEK293 cell surfaces for examination of the binding abilities of a synthetic particulate β-glucan (pβG), a product extracted from Saccharomyces cerevisiae, in this study. The binding of zymosan-FITC to hDectin-1 and mDectin-1 was inhibited by pβG at similar concentrations for 50% inhibition of binding (IC₅₀). However, the kinetics of the time course and dose response to zymosan stimulation observed for U937 and J774A.1 differed. Superoxide anion production was increased in U937 but reduced in J774A.1 when cells were treated with pβG, zymosan, or laminarin, whereas ovalbumin endocytosis was enhanced in U937 and J774A.1 treated either with pβG, zymosan, laminarin, or barley-glucan. These results indicate that the binding affinity of pβG to hDectin-1 is similar to the binding affinity to mDectin-1, and that stimulation by pβG as well as various forms of β-1,3-glucans on U937 and J774A.1 resulted in upregulation of cell activity and ovalbumin endocytosis. Additionally, other coreceptors on U937 and J774A.1 may be involved in directing different responses to superoxide anion production in these two types of cells. These results will likely contribute to further investigations on identifying the biological forms of β-glucans capable of binding its specific receptor as the effective immunomodulators.
    Biotechnology Progress 09/2010; 26(5):1391-9. · 1.85 Impact Factor
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    ABSTRACT: The immunopharmacological activities of beta-glucans with a backbone of beta-1,3/beta-1,6-linkages associated with anti-tumor, anti-viral, bacterial and fungal infections have been well documented. Dectin-1, a specific pattern recognition receptor for beta-1,3/beta-1,6-glucans, is expressed mainly on phagocytes, especially macrophages and dendritic cells (DCs). In this study, the encoding nucleotide for the carbohydrate-recognition domain (CRD) of porcine dectin-1 was sequenced for the first time, and the immunomodulatory functions of a synthetic particulate beta-glucan (p-beta-glucan) were examined. Results showed that p-beta-glucan significantly enhanced cell activity and phagocytosis in porcine alveolar macrophages (AMs), immature DCs (imDCs) and mature DCs (mDCs), in a similar way to zymosan. Zymosan enhanced dectin-1/TLR2/TLR4 expression and TNF-alpha/IL-10 production in all of three types of cell, whereas p-beta-glucan increased dectin-1/TLR4 and TNF-alpha/IL-12 production in AMs but inhibited IL-10 in mDCs. These results indicate that the complex collaborating interactions between dectin-1 and TLRs in the recognition of beta-1,3/beta-1,6-glucans with different structural features may direct different cellular responses.
    Veterinary Immunology and Immunopathology 05/2009; 131(3-4):147-57. · 1.88 Impact Factor
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    ABSTRACT: Field observations have suggested that porcine reproductive and respiratory syndrome virus (PRRSV) predispose pigs to secondary infections. The interaction between PRRSV and the secondary invaders has not yet been well elucidated. In this study, we investigated the mRNA expression of Toll-like receptors (TLR) in lymphoid organs and cells, and cytokine secretions by alveolar macrophages (AMs) and peripheral blood mononuclear cells (PBMCs) in response to pathogen-associated molecular patterns (PAMPs) in PRRSV-challenged pigs. TLR mRNA expressions were measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and cytokine concentrations were determined using commercially available ELISA kits. PRRSV infection led to significantly increased secretions of IL-1beta and IL-6 by AMs of PRRSV-infected pigs. Infection of pigs with PRRSV also resulted in an increased secretion of IL-1beta by AMs in response to lipoteichoic acid (LTA) stimulation, and IL-6 by PBMCs in response to lipopolysaccharide (LPS) and LTA stimulation. Infection of pigs with PRRSV tended to up-regulate the mRNA expression of TLR2, 3, 4, 7 and 8 in at least one of the lymphoid tissues and cells. Further research is required to demonstrate the association between the enhanced expressions of the specific TLRs and the increased susceptibility to secondary agents with more severe clinical outcomes in PRRSV-infected pigs.
    Veterinary Microbiology 12/2008; 136(3-4):266-76. · 3.13 Impact Factor
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    ABSTRACT: Antigen-presenting cells play critical roles in recognizing, presenting and processing antigens and consequently induce adequate immune response for defending infections. The immature DCs (imDCs) and mature DCs (mDCs) were obtained from in vitro differentiation of bone marrow haematopoietic cells. Results showed that poly IC stimulation down-regulated the expressions of TLR7 and TLR8 in alveolar macrophages (AMs) and imDCs. The release of IL-12 was inhibited from imDCs and mDCs in response to poly IC. Porcine reproductive and respiratory syndrome virus (PRRSV)-infection inhibited TLR3 and TLR7 expressions in AMs and imDCs at 6h post-infection (PI); both of expressions were then restored at 24h PI in both types of cells while they exhibited up-regulated IL-10 and IL-12 expression at 24h PI. Hence, the differential TLR expression patterns in porcine AMs and DCs in discrimination of the imitated viral dsRNA or PRRSV infection may determine their cytokine expressions and thus affect the resulting immune responses.
    Comparative immunology, microbiology and infectious diseases 12/2008; 33(3):197-213. · 2.99 Impact Factor
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    ABSTRACT: Phenotypic and functional property changes of bone marrow-derived immature dendritic cells (BM-imDCs) after porcine reproductive and respiratory syndrome virus (PRRSV) infection have been detailed in a previous report. A down-regulated expression of MHC I molecules along with an up-regulated expression of CD80/86 were observed in BM-imDCs after the exposure to PRRSV. In this study, we further investigate the expression of surface phenotypes of BM-imDCs in relation to their infection status. Exposure of PRRSV to BM-imDCs resulted in a down-regulated expression of MHC I and an up-regulated expression of CD80/86 in infected cells, as demonstrated by significant alterations in both percentage of expressing cells and mean fluorescence intensity (MFI) in PRRSV-positive cells. A significant suppression in MFI of MHC I and an increase in percentage of cells expressing CD80/86 were observed in noninfected bystander cells. We also demonstrated that exposure of BM-imDCs to PRRSV resulted in a significantly increased secretion of IL-1, IL-6, IL-8, IL-10 and IFN-gamma but not IL-12 or TNF-alpha. In addition, the PRRSV infection modulates cytokine expressions of BM-imDCs through their response to microbial pathogen-associated molecular patterns. These results will prove helpful in clarification of the factors that mediate host defense against PRRSV, as well as the possible interaction mechanisms between PRRSV and other microbes in the pathogenesis of PRRSV infection in pigs.
    Veterinary Microbiology 12/2008; 136(3-4):359-65. · 3.13 Impact Factor
  • Hso-Chi Chaung, Yi Lien, Wen-Bin Chung
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    ABSTRACT: Leukotrienes (LT) and chemokines are important chemotactic compounds in regulating the recruitment and activation of immune cells during pulmonary inflammatory reactions. Results showed that LTC4 release by porcine alveolar epithelial type II cells (AEC IIs) is significantly enhanced by either LTB4 or LPS stimulation. The basal level of IL-8 gene expression in AEC IIs was only 1/3 of that observed in alveolar macrophages (AMs) while AEC IIs expressed a higher basal level of monocyte chemotactic peptide-1 (MCP-1) and also in response to LPS stimulation than do AMs. The increasing basal and LT-induced MCP-1 gene expressions after 8h of incubation were observed in AEC IIs but decreased in AMs. These findings suggest that AEC IIs play an important role in initial inflammatory reactions of the lung by releasing LTC4, and that they also modulate later inflammatory reactions, evidenced by consistent elevation of MCP-1 gene expression after and during exogenous challenge in pigs.
    Research in Veterinary Science 07/2008; 86(1):78-87. · 1.77 Impact Factor
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    ABSTRACT: It is well documented that there is a delay in the development of effective immunity to porcine reproductive and respiratory syndrome virus (PRRSV) in infected and vaccinated pigs. This suggests that PRRSV might possess some inherent properties to evade host defense mechanisms during the early stage of infection. Dendritic cells (DCs) play a crucial role in the activation and control of T-cells in response to viral antigens. In this study, we investigated the phenotypic and functional property changes of bone marrow-derived immature DCs (BM-imDCs) that take place after infection by PRRSV. Results showed that BM-imDCs were permissive to PRRSV infection, as productive replication took place in these cells. A down-regulated expression of MHC I molecules along with an up-regulated expression of CD80/86 is observed at 48 h following infection. Also at 48h following PRRSV infection, a significant increase of IL-10 secretion by BM-imDCs was noticed. Results suggest that the inhibited expression of MHC I and the enhanced secretion of IL-10 by BM-imDCs after PRRSV infection might be among the strategies used by the virus to evade the host immune defenses.
    Veterinary Microbiology 07/2008; 129(3-4):281-93. · 3.13 Impact Factor
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    ABSTRACT: Real-time PCR assays were developed for quantitative detection of porcine reproductive and respiratory syndrome virus (PRRSV) and porcine circovirus type 2 (PCV2). The established real-time PCR for the quantitation of PRRSV cDNA and PCV2 DNA were found to be in the 9-log(10) linear dynamic range with excellent linearity and reliable reproducibility. Using these techniques, the distribution and quantitation of PRRSV and PCV2 in naturally infected and challenged pigs were investigated. The viral concentrations were expressed as the mean log(10) viral DNA or cDNA copy numbers per mg or ml of tested samples. For pigs infected naturally with both viruses, the lung, spleen, tonsil and lymphoid organs had the highest viral burdens with ranges from 5.73 to 8.38 and 5.65 to 6.91 for PRRSV and PCV2, respectively. The injection of formalin-inactivated Salmonella choleraesuis emulsified in complete Freund's adjuvant 1 week before and after the inoculation of both viruses resulted in PRRSV replication enhancement 2 weeks post-challenge. However, this facilitated the clearance of PRRSV 4 weeks post-challenge. Results from this study show that the established quantitative PCR could be a useful tool when applied to vaccine development and pathogenesis studies in the future.
    Journal of Virological Methods 04/2005; 124(1-2):11-9. · 1.90 Impact Factor