• Journal of Food Hygiene and Safety
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• v.13 no.2
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• pp.129-134
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• 1998

To develop an enzyme-linked immunosorbent assay (ELISA) for nivalenol (NIV), we produced polyclonal antibodies against tetraacetyl nivalenol (Ac4-NIV) and established ELISA conditions. Ac4-NIV-hemisuccinate conjugated to bovine serum albumin (Ac4-NIV-HS-BSA) was immunized with Freund's adjuvants into rabbits subcutaneously several times. By use of the antiserum showing the highest titer and Ac4-NIV-HS-HRP conjugate, we established competitive direct ELISA (cdELISA). Standard curve of cdELISA showed that the detection range of Ac4-NIV was about 10~5,000 ng/ml (ppb). The cross-reactivities of the polyclonal antibody towards Ac4-NIV and acetyl T-2 were 100 and 70% respectively, and those towards NIV, deoxynivalenol, 3-acetyl deoxynivalenol, 15-acetyl deoxynivalenol, triacetyl deoxynivalenol, fusarenonX, and T-2 were less than 0.1%. When cdELISA was applied to NIV-spiked corns followed by extraction with 70% acetonitrile and acetylation with acetic anhydride in pyridine, the recovery rates of the Ac4-NIV were 108, 143, and 70% (average, 107%) in the levels of 100, 300, and 1,000 ng/g (ppb), respectively.

• Journal of Microbiology and Biotechnology
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• v.14 no.3
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• pp.612-619
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• 2004

A competitive direct enzyme-linked immunosorbent assay (cdELISA) was developed for selective and rapid detection of a glycopeptide antibiotic, teicoplanin (TP). TP was conjugated to bovine serum albumin (BSA) for use as an immunogen. Repeated subcutaneous injections of 0.5 mg of the conjugate was effective in generating specific polyclonal antibody (PAb) toward TP in rabbits, as determined by cdELISA. TP-horseradish peroxidase conjugate (TP-HRP) was used as an enzyme marker. The cdELISA was developed based on a competition reaction between TP-BSA PAb and TP-HRP conjugate. The TP-BSA PAb was highly sensitive (detection limit, 0.3 ng/ml and specific toward teicoplanin, showing no cross-reactivity to other glycopeptide antibiotics including vancomycin. There were good correlations ($r^2$=0.84 and 0.76, respectively) between cdELISA and microbiological assay, and high-performance liquid chromatography. The cdELISA system developed in this work is expected to be useful not only for selective and rapid monitoring of TP but also for study of TP pharmacokinetics.

• Microbiology and Biotechnology Letters
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• v.25 no.4
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• pp.414-419
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• 1997

In order to develop an enzyme-linked immunosorbent assay (ELISA) for deoxynivalenol (DON) in com, we produced a specific monocl- onal antibody and established ELISA conditions. After the spleen cells from mice immunized with DON-bovine serum albumin conjugate were fused with S$_{p}$2/0 myeloma cells, a hybridoma cell 3G7 producing anti-DON antibody was screened by ELISA. From the standard curve of competitive direct ELISA (cdELISA) using 3G7 monoclonal antibody and DON-HRP conjugate, the detection range of DON showed 3-3,000 ng/ml (ppb). The monoclonal antibody showed some cross-reactivities against DON analogues such as 15 acetyl-DON (110%), nivalenol (5.0%), 3 acetyl-DON (1.7%), fusarenon-x (0.72%), and T-2 (0.59%). When the cdELISA was applied to the spiked coms after extracting with 60% methanol and diluting 5- fold with washing buffer, the assay recoveries of DON were 313, 163, 106, and 88.9% (av., 168%) in the levels of 200, 600, 2,000, and 6,000ng/g, respectively. For the quantitation of DON in coms, 30 samples kept under two different storage conditions of cold and room temperature were assayed by cdELISA. The mean detection concentrations were 595 (detection range, 0-2,750) and 2,448 (detection range, 0-4,500) ppb, respectively.

• Korean Journal of Food Science and Technology
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• v.41 no.2
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• pp.215-219
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• 2009

To conduct a risk assessment of $AFB_1$ intake, $AFM_1$, which is a metabolite of $AFB_1$ in the human and porcine urine, was determined by competitive direct ELISA (cdELISA). The detection limit of cdELISA using anti-$AFM_1$ antibody and $AFB_1$-HRP conjugate was 10 pg/mL. The recoveries of $AFM_1$ were 117-167% after the addition of $AFM_1$ in the human urine in a range of 3-100 pg/mL. 165 samples (95.5%) of those obtained from 172 persons evidenced measurable levels of urinary $AFM_1$. The detected $AFM_1$ ranges were 0-11.6 pg/mL and the average level of $AFM_1$ contamination was 2.74${\pm}$ 1.89 pg/mL. The estimated amount of $AFM_1$ excretion in the human urine was 3.97 ng/day and the estimated $AFB_1$ intake amount was 79.4 ng/day. The probable daily intake (PDI) of $AFB_1$ by the subjects was estimated to be 1.28 ng/kg bw/day, which was higher than the tolerable daily intake (TDI, 0.15 ng/kg bw/day). In the case of porcine urine, the $AFM_1$ ranged between 0.97-26.7 pg/mL and the average contaminated $AFM_1$ was 10.62${\pm}$4.39 pg/mL. The estimated amount of $AFM_1$ excretion in the porcine urine was 27.6 ng/day, and the estimated $AFB_1$ intake amount was 551 ng/day.

• Journal of Food Hygiene and Safety
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• v.18 no.3
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• pp.95-100
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• 2003

Competitive direct enzyme-linked immunosorbent assay(cdELISA) of aflatoxin $B_1$ ($AFB_1$) in deonjang(Korean-style soybean paste) and kochujang(fermented hot peppersoybean paste) and the level of $AFB_1$ in modern or traditional style deonjang and gochujang, produced in Korea, was surveyed by cdELISA. From the standard curve of the cdELISA, the detection limit of $AFB_1$ was 0.2 ng/m/. The average recovery of $AFB_1$ was 71.5% in the range of 1~100 ng/g after spiking $AFB_1$ into deonjang and it means that it could be possible to detect the $AFB_1$ in these range by the cdELISA in deonjang. Among the 30 kochujangs tested, no $AFB_1$ was detected in kochujangs. Among the 30 deonjangs, $AFB_1$ was detected in 6 ones in the range of 1.0~6.0 ng/g. The occurrence of $AFB_1$ in deonjang and kochujang tested in this study was less than the Korea Standard and Specification of aflatoxin in foods (10 ppb).

• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.686-692
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• 2004

To develop the enzyme-linked immunosorbent assay (ELISA) for the analysis of N-acetylehitooligosaccharides (NACOS) and chitooligosaccharides (COS), specific antibodies (Abs) were produced, and their properties were compared. N-acetylehitohexaose (NACOS6), chitohexaose (COS6), and COS mixture (COSM) conjugated to bovine serum albumin (BSA) were used to immunize rabbits. By the use of specific Abs and NACOS6-horseradish peroxidase (HRP), COS6-HRP, and COSM-HRP conjugates, competitive direct ELISA (cdELISA) was developed. The detection limits of NACOS6 by the anti-NACOS6 Ab and COS6 by the anti-COS6 and the anti-COSM Abs in the cdELISAs were about 0.2, 2, ana 2 ng/ml (ppb), respectively. In the cdELISA, the anti-NACOS6 Ab was found to recognize NACOS3-NACOS6, but not N-acetyl-D-glucosamine (GlcNAc), NACOS2, and COSs; the anti-COS6 Ab recognized COS2-COS6 and COSM, but not glucosamine (GlcN) and NACOSs. The recognition pattern of the anti-COSM Ab was almost the same as that of the anti- COS6 Ab, except that the former recognized COS2 and COS3 slightly better than the latter.

• Microbiology and Biotechnology Letters
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• v.24 no.5
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• pp.630-635
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• 1996

For a survey of the occurrence of aflatoxin M$_{1}$ (AFM$_{1}$) in domestic cow's milk, we developed an enzyme-linked immunosorbent assay (ELISA) system, and quantitated the toxin in cow's milk. In order to produce specific antibodies AFM, conjugated to bovine serum albumin (AFM$_{1}$-BSA) and Freund's adjuvant were immunized subcutaneously to rabbits. By use of the antiserum showing the highest titer and AFB$_{1}$-HRP conjugate, we established a competitive direct ELISA (cdELISA) for AFM$_{1}$, whose detection limit was 0.003 ppb. The cross-reactivities of the antiserum against aflatoxin M$_{1}$ M$_{2}$, B$_{1}$, B$_{2}$, G$_{1}$, G$_{2}$, B$_{2a}$, and G$_{2a}$, were 100, 29.9, 25.0, 2.7, 13.0, 0.65, 0, and 0%, respectively. When the cdELISA was applied to the cow's milk spiked with AFM$_{1}$ and followed by cleanup with C$_{18}$ cartridge, the mean recovery of the assay was 104% (mean of CV, 6.4%) in the final concentration of 0.01-1 ppb (10-1, 000 ppt). When cow's milk samples gathered from markets and farms were assayed by the cdELISA, the mean concentration and SD of AFM$_{1}$ was 80.4 $\pm$ 55.0 ppt (n=64; range, 5.6-280 ppt).

• The Korea Journal of Herbology
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• v.24 no.3
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• pp.29-37
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• 2009

Objectives : The present study was carried out to investigate the effect of Trichosanthis Radix extract (TRE) on the proliferation and activation of eosinophils which were prepared from lung cells of asthma-induced mice by ovalbumin (OVA) treatment. Methods : C57BL/6 mouse was exposed to OVA three times a week for 6 weeks. The mouse lung tissues were dissected out, chopped and dossiciated with collagenase (1 $\mu$g/ml). Eosinophils were activated by rmIL-3/rmIL-5 co-treatments. The lung cells were treated with TRE, incubated for 48 hr at 37$^{\circ}C$, and analyzed by flow cytometer, ELISA and RT-PCR methods Results : To measure cytotoxicity, mouse lung fibroblast cells (mLFCs) were pretreated with various concentrations of TRE. TRE at 100 $\mu$g/ml, the highest concentration, examined did not have any cytotoxic effects on mLFCs. In FACS analysis, number of granulocyte/lymphocyte, CD3e-/CCR3+, CD3e+/CD69+, CD4+/CD8+ T cells in asthma-induced lung cells were significantly decreased by TRE treatment compared to the control group. But CD4+/CD25+ T cells were not examined significant change in lung cells treated with TRE. In ELISA analysis, production levels of IL-3, IL-5, IL-13 and histamine in asthma-induced lung cells, which were induced by rIL-3 plus rmIL-5 co-treatment, were significantly decreased by TRE treatment. Conclusions : The present data suggested that Trichosanthis Radix on the inhibition of parameters associated with asthma responses in eosinpophils, and thus implicate the possibility for the clinical application of Trichosanthis Radix.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.6
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• pp.1152-1159
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• 1998

In order to develop more rapid and reproducible analysis of biotin known as vitamin H, attempts were made to establish the condition for enzyme linked immunosorbent assay(ELISA) compared with traditional microbiological assay(MBA). Antibiotin and antiserum were obtained from the immunized rabbits injected with emulsion of biotin KLH conjugate and Freund's adjuvant. The antiserum showed cross reactivity on biocytin, a derivative of biotin, which is converted to biotin in intestine, at the rate of 177%(median inhibitory concentration(IC50)=12.58ppb), but not on other derivatives such as desthiobiotin, diaminobiotin and 2 imino biotin. Specific antibody for biotin was purified from the antiserum through protein A column and desalting column. The conditions of competitive direct ELISA (cdELISA) were established. Detection range of biotin concentration by cdELISA was 0.01∼300ng/ ml(ppb). In the spike test with milk, fruit flake and pine carrot juice, the correlation coefficient between two methods of MBA and ELISA was reliably consistent at the value of r=0.992. But detection of biotin by microbiological assay(MBA) was rather restricted in range and nonspecific. Detection range of biotin by MBA was 0.1∼0.5ng/ml(ppb). It showed cross reactivities on biocytin and desthiobiotin at the rate of 80.1% and 66.7%, respectively. In conclusion, ELISA revealed a significant improvement compared with MBA for the biotin detection in terms of sensitivity, detection range and cross reactivity. In addition, a variety of samples could be analyzed rapidly and conveniently at one time by using ELISA. These results strongly suggest that the ELISA is very promising for the practical application to detect biotin contents in a wide range of food stuffs.

• 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.