• Title/Summary/Keyword: 2-site ELISA

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Application of Oral Fluid Sample to Monitor Porcine circovirus-2 Infection in Pig Farms (구강액을 이용한 양돈장의 Porcine circovirus-2 감염에 대한 모니터링)

  • Kim, Won-Il
    • Journal of Veterinary Clinics
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    • v.27 no.6
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    • pp.704-712
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    • 2010
  • Porcine circovirus-2 (PCV2) has been implicated in many clinical diseases/syndromes that are now referred to as PCV-associated diseases (PCVAD). Due to significant economic losses caused by PCVAD, many swine operations have launched extensive monitoring programs for PCV2. Traditional serum sampling is, however, rather expensive and laborious, hampering effective large scale pathogen surveillance. A field-based longitudinal study was conducted to assess the utility of pen-based oral fluid sample as an alternative to serum for herd PCV2 testing. Six pens (25 pigs/pen) at each of 3 different sites were used in the study. One oral fluid and 5 random serum samples per pen were collected at 3, 5, 8, 12, and 16 weeks of age, and the sera were pooled by pen for testing. All samples were tested for PCV2 by real-time PCR and for antibodies by indirect fluorescent antibody test (for both anti-PCV2 IgG and IgA) and 3 ELISA assays (blocking ELISA, indirect ELISA, and IgG/IgM sandwich ELISA). PCV2 DNA was detected in oral fluid samples sporadically until 8 weeks and in all pens at 16 weeks. PCV2-specific IgG was detected in oral fluid samples at 3 weeks and persisted until 5 to 8 weeks in all sites. Anti-PCV2 IgG and IgA were detectable in oral fluid samples collected at 16 weeks from all of the pens at 1 site. The detection of PCV2 and anti-PCV2 antibody in oral fluid samples correlated positively with results on pooled sera, suggesting that oral fluids can be a cost-effective alternative to serum for herd monitoring of PCV2 infection.

Comparison of Some 3-(Substituted-Benzylidene)-1, 3-Dihydro-Indolin Derivatives as Ligands of Tyrosine Kinase Based on Binding Mode Studies and Biological Assay

  • Olgen, Sureyya
    • Archives of Pharmacal Research
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    • v.29 no.11
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    • pp.1006-1017
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    • 2006
  • A series of 3-(substituted-benylidene)-1, 3-dihydro- indolin-2-one, 3-(substituted-benylidene)-1, 3-dihydro- indolin-2-thione and 2, 2'-dithiobis 3-(substituted-benylidene)-1, 3-dihydro-indole derivatives was investigated as inhibitor of $p60^{c-Src}$tyrosine kinase by performing receptor docking studies and inhibitory activity toward tyrosine phosphorylation. Some compounds were shown to be docked at the site, where the selective inhibitor PP1 [1-tert-Butyl-3-p-tolyl-1H-pyrazolo[3,4-d]pyrimidine-4-yl-amine] was embedded at the enzyme active site. Evaluation of all compounds for the interactions with the parameters of lowest binding energy levels, capability of hydrogen bond formations and superimposibility on enzyme active site by docking studies, it can be assumed that 3-(substituted-benzylidene)-1, 3-dihydro-indolin-2-one and thione derivatives have better interaction with enzyme active site then 2, 2'-dithiobis 3-(substituted-benzylidene)-1, 3-dihydro indole derivatives. The test results for the inhibitory activity against tyrosine kinase by Elisa method revealed that 3-(substituted-benylidene)-1, 3-dihydro- indolin-2-thione derivatives have more activity then 3-(substituted-benylidene)-1, 3-dihydro- indolin-2-one derivatives.

Effects of Mutagenesis for Glycosylation Sites of Recombinant Human EPO During Production from Cultured CHO Cell

  • Lee, Hyun-Gi;Seong, Hwan-Hoo;Im, Seok-Ki;Chung, Hee-Kyoung;Lee, Poongyeon;Lee, Yeun-Kun;Min, Kwan-Sik;Chang, Won-Kyoung;Lee, Hoon-Taek
    • Proceedings of the Korean Society of Embryo Transfer Conference
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    • 2002.11a
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    • pp.97-97
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    • 2002
  • Human eryhropoietin (EPO) is acidic glycoprotein hormone that plays key role in hematopoiesis by facilitating differentiation of erythrocyte and formation of hemoglobin (Hb) and is used for the treatment of anemia. Human EPO is consist of 166 amino acids which is modified by three N-glycosylations (24, 38, 83) and single O-glycosylation (126). N-glycosylation is reported to be related to the cellular secretion and activity of EPO. In this study, we examined effects of mutagenesis in glycosylation site of recombinat hEPO for the cellular secretion during production from cultured CHO cell. We produced rhEpo which was cloned by PCR from human liver cDNA (TaKaRa) in cultured CHO cell. Using supernatant of the culture, ELISA assay and western analysis were performed. To estimate biological activity, 20IU of rhuEpo was subcutaneously injected into four ICR mice. After 8 days, HCT level was increased average 13 per cent, RBC was increased ca. 2${\times}$10$\^$6//${\mu}\ell$. In disease model Rat (anemia c-kit, WSRC-WS/WS), HCT was increased ca. 12%, RBC was increased ca. 1.6${\times}$10$\^$6//${\mu}\ell$. These results suggests that rhEpo we produced has biological activity. To remove glycosylation site by substituting 24, 38, 83, and 126th asparagine (or serine) with glutamic acid, overlapping -extension site-directed mutagenesis was performed. To add novel glycosylation sites, 69, 105th leucine was mutated to asparagine. Mutant EPO construct was transfected into CHO cell. Supernatant of the cell culture was analyzed using ELISA assay with monoclonal anti-EPO antibody (Medac, Germany). Since, several reports for mutagenesis of glycosylation sites showed case-by-case results, we examined both transient expression and stable expression. Addition of novel glycosylation sites resulted no secretion while deletion mutants had little effect except some double deletion mutants (24/83 and 38/83) and triple mutant. We suggest that not single but combination of glycosyl group affect secretion of EPO.

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Effects of Changes in Glycosylation Sites on Secretion of Recombinant Human Erythropoietin in Cultured CHO Cells

  • Lee, H. G;Lee, P. Y.;Lee, Y. K.;Kim, S. J.;H. K. Chung;M. K. Seo;Park, J. K.;K. S. Min;W. K. Chang
    • Korean Journal of Animal Reproduction
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    • v.27 no.4
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    • pp.299-307
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    • 2003
  • The effects of additions/deletions in glycosylated residues of recombinant human EPO (rhEPO) produced in CHO-K1 on their secretion were examined. hEPO cDNA was amplified from human liver mRNA and cloned into the pCR2.1 TOPO. Using overlapping-extension site-directed mutagenesis method, glycosylation sites at 24th, 38th, 83rd, and 126th were respectively or accumulatively removed by substituting its asparagine (or serine) with glutamine. To add novel glycosylation sites, 69 and 105th leucine was mutated to asparagine. Mutant and wild type rhEPO constructs were cloned into the pcDNA3 expression vector with CMV promoter and transfected into CHO cell line, CHO-K1, to produce mutant rhEPO mutant rhEPO proteins. Enzyme-linked immunosorbant assay (ELISA) and Western analysis with monoclonal anti-EPO antibody were performed using supernatants of the cultures showing transient and stable expressions respectively. Addition of novel glycosylation reduced rhEPO secretion dramatically while deletion mutants had little effect except some double deletion mutants ($\Delta$24/83 and $\Delta$38/83) and triple mutant ($\Delta$24/38/83). This fact suggests that not single but combination of changes in glycosyl groups affect secretion of rhEPO in cell culture, possibly via changes in their conformations.

Effect of Timing of IPTG Addition on Expression of Turnip Mosaic Virus Coat Protein Gene in Escherichia Coli (IPTG의 첨가 시간이 대장균(Escherichia coli)에서 순무 모자이크 바이러스(TuMV)의 외피단백질 발현에 미치는 영향)

  • Kim, Su-Joong;Park, Won-Mok;Ryu, Ki-Hyun;Lee, Sang-Seon;Lee, Se-Yong
    • Korean Journal Plant Pathology
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    • v.13 no.4
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    • pp.248-254
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    • 1997
  • Expression vector (pGEX-Tu) for the coat protein (CP) gene of turnip mosaic virus Ca strain (TuMV-Ca) was constructed by incorporation of TuMV CP gene into pGEX-KG vector which had ${\beta}$-galactosidase gene and IPTG (isopropylthio-${\beta}$-D-galactoside) induction site. The results of ELISA and western hybridization indicated that optimal condition of the expression were when IPTG and western hybridization indicated that optimal condition of the expression were when IPTG induction was carried out on YTA medium with ampicillin in 2 hours after the E. coli seed inoculation ($A_{595}$=0.1/ml). TuMV CP gene was expressed with GST (Glutathion S-Transferase) gene fusion system, and the size of fusion protein was estimated to be 59kDa, for TuMV CP was 33 kDa and GST was 26 kDa.

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Monoclonal antibodies to recombinant Der p2, a major house dust mite allergen: specificity, epitope analysis and development of two-site capture ELISA

  • Yong, Tai-Soon;Lee, Sang-Mi;Park, Gab-Man;Lee, In-Yong;Ree, Han-Il;Kim, Kyung-Sup;Oh, Sang-Hwan;Park, Jung-Won;Hong, Chein-Soo
    • Parasites, Hosts and Diseases
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    • v.37 no.3
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    • pp.163-169
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    • 1999
  • House dust mite allergens have been well established as sensitizing agents that are important in the induction of allergic diseases. In order to analyze epitopes of the allergen and to develop a quantitative method of the allergen exposure, monoclonal antibodies against a recombinant Der p 2 (rDer p 2), one of the major allergens of Dermatophogoides pteronyssinus, were produce. Four monoclonal antibodies produced wee species-specific and did not cross-react to the D. farinae crude extract. Two of the monoclonal antibodies were found to be IgG1 and the others were IgM. For the analysis of epitopes, a Der p 2 cDNA encoding 126 amino acids (aa) was dissected into three fragments with several overlapping peptides, A (aa residues 1-49), B (44-93), and C fragment (84-126). Three monoclonal antibodies showed reactivities to the recombinant B fragment and to the full-length rDer p 2, but one monoclonal antibody reacted only with the full-length rDer p 2. Two-site capture ELISA was developed using two different monoclonal antibodies for quantitating Der p2 in house dust. The sensitivity limit was 4ng/ml with rDer p2 and $8{\;}\mu\textrm{g}/ml$ with the d. pteronyssinus crude extract. The result suggested that the assay using monoclonal antibodies against rDer p2 could be useful for the environmental studies and for the standardization of mite allergen extracts.

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ANALYSIS ON THE PREDICTOR OF DISEASE PROGRESSION IN REFRACTORY PERIODONTITIS (난치성 치주염의 질환진행 예견 인자에 관한 분석)

  • Lee, Hae-Joon;Choi, Sang-Mook;Chung, Chong-Pyoung
    • Journal of Periodontal and Implant Science
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    • v.23 no.1
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    • pp.109-126
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    • 1993
  • Refractory periodontitis manifest progressive attachment loss in a rapid and unrelenting manner regardless of the type or frequency of therapy applied. The purpose of this study was ta evaluate the relation between the level of cytokines in GCF and periodontopathic microflora with disease activity of refractory periodontitis. Selection of patients with refractory periodontitis (7 males, 3 females) were made by long term clinical observation including conventional clinical history and parameters. Teeth that showed pocket depth greater than 6mm were selected as sample teeth. Subjects were examined at baseline and after 3 months. Prior to baseline test, individual acrylic stent was fabricated. Reference grooves were made on each sample tooth site. Pocket depth and attachment loss were measured by Florida Probe. Gingival index was measured at 4 sites each sample teeth. Disease activity was defined as attachment loss of ${\ge}$ 2.1mm, as determined by sequential probing and tolerance method. The pattern and amount of alveolar bone resorption was observed with quantitative digital subtraction image processing radiography. Morphological analysis of subgingival bacteria was taken by phase contrast microscopy. Predominant cultivable bacterial distribution and frequency were compared between disease-active and disease-inactive site using immunofluorescence microscopy and selective microbial culturing. Levels of $interleukin-l{\beta}$, 2, 4, 6 and $TNF-{\alpha}$ in GCF and blood serum sample were quantified by ELISA. In active sites, P. intermedia was significantly increased to compare with inactive site. $IL-1{\beta}$, IL-2, IL-6 and $TNF-{\alpha}$ in GCF were increased in active sites and IL-2 in serum was increased in active patients significantly. Alveolar bone loss in active site was correlated with $IL-1{\beta}$, IL-2 in GCF. And loss of attachment in active site was correlated with IL-2 in GCF. These results demonstrate that IL-2 in serum, $IL-1{\beta}$, IL-2, IL-6 and $TNF-{\alpha}$ in GCF, P, intermedia might be used as possible predictors of disease activity in refractory periodontitis before it is clinically expressed as attachment loss and quantitative alveolar bone change.

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Characterization and Epitope Mapping of KI-41, a Murine Monoclonal Antibody Specific for the gp41 Envelope Protein of the Human Immunodeficiency Virus-1

  • Shin, Song-Yub;Park, Jung-Hyun;Jang, So-Youn;Lee, Myung-Kyu;Hahm, Kyung-Soo
    • BMB Reports
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    • v.31 no.1
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    • pp.58-63
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    • 1998
  • In this study, a mouse monoclonal antibody (mAb) against gp41(584-618), the immunodominant epitope protein, was generated. For this purpose, BALB/c mice were immunized with double branched multiple antigenic peptides derived from the HIV-1 gp41(584-618) sequence, and antibody-secreting hybridoma were produced by fusion of mice splenocytes with SP2/0 myeloma cells. One clone producing an antigen specific mAb, termed KI-41(isotype IgG1) was identified, whose specific reactivity against gp41(584-618) could be confirmed by ELISA and Western blot analysis. Epitope mapping revealed the recognition site of the mAb KI-41 to be located around the sequence RILAVERYLKDQQLLG, which comprises the N-terminal region within the immunized gp41(584-618) peptied. Since this mAb recognizes this specific epitope within the HIV-1 gp41 without any cross-reactivity to other immunodominant regions in the HIV-2 gp35, KI-41 will provide some alternative possibilities in further applications such as the development of indirect or competitive ELISA for specific antibody detection in HIV-1 infection or for other basic researches regarding the role and function of HIV-1 gp41.

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One-Step Simultaneous Immunochromatographic Strip Test for Multianalysis of Ochratoxin A and Zearalenone

  • Shim, Won-Bo;Dzantiev, Boris B.;Eremin, Sergei A.;Chung, Duck-Hwa
    • Journal of Microbiology and Biotechnology
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    • v.19 no.1
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    • pp.83-92
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    • 2009
  • Individual immunochromatographic assays (ICG) for ochratoxin A (OTA) and zearalenone (ZEA) were optimized and used in the development of a one-step simultaneous immunochromatographic assay (OS-ICG) for the rapid multianalysis of two mycotoxins in corn samples. The nitrocellulose membrane of the OS-ICG was treated with OTA-bovine serum albumin (BSA), ZEA-ovalbumin (OVA), and anti-mouse IgG in the OTA test, ZEA test, and control zones, respectively. Monoclonal antibody-gold conjugates (OTA3 MAb-gold and ZEA2C5 MAb-gold) were sprayed onto the conjugate pad. The visual detection limits were 2.5 and 5 ng/ml for OTA and ZEA, respectively, and the results were obtained within 15 min after starting the analysis. An efficient, simple, and rapid extraction method using 30% MeOH/PBS was established and validated by analyzing the corn samples spiked with OTA/ZEA mixtures (0/0, 5/10, 10/20, and $20/30\;{\mu}g/kg$). The cut-off values of the OS-ICG for the spiked corn were 5 and $10\;{\mu}g/kg$ for OTA and ZEA, respectively. Natural corn samples were analyzed by OS-ICG, direct competitive enzyme-linked immunosorbent assay (DC-ELISA), and HPLC. Results of the OS-ICG were in good agreement with those obtained by DC-ELISA and HPLC. The developed OS-ICG offers a rapid, easy-to-use, and portable analytical system and can be used as a convenient qualitative tool for the on-site simultaneous determination of OTA and ZEA in cereals, food, and agricultural products in one analytical cycle.

Production of a Recombinant Anti-Human CD4 Single-Chain Variable-Fragment Antibody Using Phage Display Technology and Its Expression in Escherichia coli

  • Babaei, Arash;Zarkesh-Esfahani, Sayyed Hamid;Gharagozloo, Marjan
    • Journal of Microbiology and Biotechnology
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    • v.21 no.5
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    • pp.529-535
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    • 2011
  • Single-chain variable fragment (scFv) is a fusion protein of the variable regions of the heavy (VH) and light (VL) chains of immunoglobulin, connected with a short linker peptide of 10 to about 20 amino acids. In this study, the scFv of a monoclonal antibody against the third domain of human CD4 was cloned from OKT4 hybridoma cells using the phage display technique and produced in E. coli. The expression, production, and purification of anti-CD4 scFv were tested using SDS-PAGE and Western blot, and the specificity of anti-CD4 scFv was examined using ELISA. A 31 kDa recombinant anti-CD4 scFv was expressed and produced in bacteria, which was confirmed by SDS-PAGE and Western blot assays. Sequence analysis proved the ScFv structure of the construct. It was able to bind to CD4 in quality ELISA assay. The canonical structure of anti-CD4 scFv antibody was obtained using the SWISS_MODEL bioinformatics tool for comparing with the scFv general structure. To the best of our knowledge, this is the first report for generating scFv against human CD4 antigen. Engineered anti-CD4 scFv could be used in immunological studies, including fluorochrome conjugation, bispecific antibody production, bifunctional protein synthesis, and other genetic engineering manipulations. Since the binding site of our product is domain 3 (D3) of the CD4 molecule and different from the CD4 immunological main domain, including D1 and D2, further studies are needed to evaluate the anti-CD4 scFv potential for diagnostic and therapeutic applications.