• The Korean Journal of Pesticide Science
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• v.5 no.2
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• pp.1-12
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• 2001

A competitive indirect enzyme-linked immunosorbent assay (ci ELISA) for the organophosphorus insecticide acephate, O,S-dimethyl acetylphosphoramidothioate, was developed using a polyclonal antibody. Three different haptens mimicking the analyze and containing hexanoic acid moiety as a linker were synthesized, and then conjugated with the carrier proteins bovine serum albumin and keyhole limpet hemocyanin by the N-hydroxysuccinimide active ester method. Polyclonal antibodies raised against hapten-KLH conjugates in rabbits and the hapten-BSA conjugates as coating antigens were screened and selected for the assay in the homologous and/or heterologous ELISA system. The effects of various assay conditions, including blocking reagents, detergent content, organic solvents, pH, and preincubation of tile mixture of the polyclonal antibody and the analyze on the sensitivity were evaluated. The $IC_{50}$ value of acephate of 110 ng/mL was obtained in an optimized heterologous system using hapten-3-BSA as a coating antigen and a polyclonal antibody 8377, showing the detection range of 10-1000 ng/mL and the lowest detection limit of 4 ng/mL. The cross-reactivities of the structurally related insecticides, including methamidophos were less than 0.02%. These results indicate that the ELISA could be a convenient and alternative tool for monitoring acephate residues in agricultural products and environmental samples.

• Journal of fish pathology
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• v.22 no.2
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• pp.167-172
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• 2009

Antibody-detection enzyme-linked immunosorbent assay (ELISA) was performed to determine whether the absorbance value of ELISA is influenced by the different serum storage conditions of olive flounder Paralichthys olivaceus. Flounder antiserum to bovine serum albumin was stored at -80, -20, 4 and 20${^{\circ}C}$ for 1, 30, 69 and 124 days, respectively. In addition, the flounder antisera were frozen at -80 and -20${^{\circ}C}$, respectively and then repeated 1, 5 and 10 thaw-freeze cycles. No significant difference was shown in ELISA optical density (O.D.) values of sera, which were stored at the above mentioned storage conditions during 124 days. ELISA O.D. values of unfrozen serum samples, which were previously stored at 4${^{\circ}C}$, were almost similar to those of sera undergoing 1, 5, and 10 freeze-thaw cycles after stored at -80 or -20${^{\circ}C}$. In conclusion, the ELISA O.D. values of flounder sera were not affected by various storage conditions: different temperatures (-80, -20, 4 and 20${^{\circ}C}$), durations of storage (1, 30, 69 and 124 days), and repeated thaw-freeze cycles (1, 5, and 10 times).

• Journal of Food Hygiene and Safety
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• v.12 no.4
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• pp.281-287
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• 1997

We have reported a sensitive, specific and simple direct competitive ELISA method to detect aflatoxin in agricultural commodities. We evaluated the ELISA for practical use to detect aflatoxins contaminated in the domestic and foreign agricultural commodities. The detection limits of the direct ELISA for residual aflatoxins in rice, pine nuts, corns, almonds, bean nuts, and pistachio were 10 ppb and in peanuts and cashew nuts were 20 ppb, which were elucidated from the standard curves of ELISA for aflatoxin fortified into the agricultural commodities. Residue studies of naturally contaminated aflatoxins in the agricultural commodities were also carried out by using direct ELISA. As the results of the studies, it was revealed that there were no residues of aflatoxins in 20 rice samples produced in south Korea, 20 pine nut samples in south Korea (9 samples), USA (1 sample) and China (10 samples), each of 20 almond, pistachio and bean nut samples in USA. However, aflatoxin residues were detected in corn samples imported from north Korea (350∼585 ppb in 2 of 3 samples), from USA (109*326 ppb in 6 of 6 samples) and domestic corns (61-326 ppb in 7 of 17 samples). The toxins were contaminated in corn imported from USA for popcorn (17∼20 ppb, in 3 of 10 samples) whereas no residues were detected in corn from south Korea and China. In case of cashew nuts imported from India, 11.4∼23.1 ppb of aflatoxins were detected in 4 from 20 samples. Most of the contaminated foods were harvested before 1995. Thus, hygienic managements of the foods should be required during storage and circulation at market.

• Parasites, Hosts and Diseases
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• v.51 no.4
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• pp.433-440
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• 2013

Toxocariasis is a worldwide zoonosis caused by larvae of ascarid nematodes of dogs or cats, Toxocara canis or T. cati. Diagnosis of human toxocariasis currently relies on serology that uses T. canis excretory-secretory antigen to detect specific IgG antibodies by ELISA. We investigated the serodiagnostic efficacy of ELISA using crude antigen of T. canis larvae (TCLA). Serum specimens of 64 clinically confirmed toxocariasis, 115 healthy controls, and 119 other tissue-invading helminthiases were screened by ELISA using TCLA. The ELISA using TCLA showed 92.2% (59/64 patient samples) sensitivity and 86.6% (103/119) specificity. Its positive diagnostic predictivity was 78.7% and negative predictivity was 97.8%. No serum of healthy controls reacted but that of anisakiasis (45.5%), gnathostomiasis (19.2%), clonorchiasis (15.8%), sparganosis (11.1%), and cysticercosis (6.3%) cross-reacted. Immunoblot analysis on TCLA recognized antigenic proteins of 28- and 30-kDa bands in their dominant protein quantity and strong blotting reactivity. The present results indicate that the ELISA using our TCLA antigen is acceptable by the sensitivity and specificity for serodiagnosis of human toxocariasis. ELISA with TCLA is recommended to make differential diagnosis for patients with any sign of organ infiltration and eosinophilia.

• Tuberculosis and Respiratory Diseases
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• v.59 no.1
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• pp.47-52
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• 2005

Background : Chlamydia pneumoniae is a clinically important pathogen, the diagnosis of such infection being based mainly on serology. Microimmunofluorescence (MIF) is the current standard diagnostic method, but is subjective and time-consuming, so the authors tested the serology of chronic cough patients using an EILSA method for the Chlamydial antibody, which is a more objective method, and compared the results with those of the standard method. Method : Thirty-five patients, who visited Kangwon National University Hospital between August 2003 and July 2004, were evaluated. A MIF and ELISA tests were used to determine C. pneumoniae antibody titers. Nasopharyngeal aspirates were examined by polymerase chain reaction (PCR). The Spearman rank correlation test was used for data analysis. Results : Sensitivities of ELISA for IgG, IgA and IgM, as judged by MIF, were 84.0, 84.0 and 40.0% and the specificities were 60.0, 60.0 and 96.7%, respectively. Three patients were Chlamydia PCR positive. Conclusion : ELISA can be a useful tool for studying the seroprevalence of Chlamydia pneumoniae. However, further studies will be required prior to its clinical use.

• BMB Reports
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• v.31 no.5
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• pp.519-523
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• 1998

We have previously reported that anti-glucose-6-phosphate dehydrogenase (G6PD) serum raised against native G6PD (nG6PD) enzyme recognized nG6PD antigen poorly in competitive enzyme-linked immunosorbent assay (ELISA) (Kim, 1997). In the present study, we investigated whether anti-G6PD serum raised against nG6PD can react with denatured G6PD effectively in competitive ELISA. We used partially active G6PD (paG6PD) by repeated freeze-thawing or SDS-denatured G6PD (SDS-G6PD) as both immobilized and soluble antigens, and anti-G6PD serum raised against nG6PD for competitive ELISA. The polystyrene cuvettes coated with either paG6PD or SDS-G6PD were challenged with a mixture of a limiting amount of anti-G6PD serum and various doses of paG6PD or SDS-G6PD as competitors, followed by incubation with alkaline phosphatase-anti-IgG conjugate. The competitive ELISA with paG6PD or SDS-G6PD antigen exhibited the sigmoidal dose-response curve characteristic of competition immunoassays. Furthermore, Triton-denatured G6PD (Triton-G6PD) was used in competitive ELISA. The paG6PD, SDS-G6PD, or Triton-G6PD used as competitors increased the inhibition of antibody binding to immobilized either of nG6PD or denatured G6PD compared with nG6PD competitor. The inhibition by denatured G6PD competitors was more pronounced at high competitor concentrations than at low counterparts. We conclude that anti-G6PD serum raised against nG6PD can effectively react with denatured G6PD in competitive ELISA and that our anti-G6PD serum recognizes denatured enzymes better than active enzymes.

• Korean Journal of Veterinary Research
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• v.37 no.3
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• pp.613-618
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• 1997

Direct competitive enzyme linked immunosorbent assay(ELISA) with monoclonal antibodies have been studied for quantitative determination of T-2 toxin from the mold corn. The T-2HS, T-2HS-BSA, T-2HS-HRP and monoclonal antibodies against T-2 toxin produced in the studies were qualified for quantitative ELISA test of T-2 toxin. The mean recovery rate from ground com spiked T-2 toxin was 83%. The meaning range of the T-2 test was 60ng to $2{\mu}g$. According to the recovery results with the com spiked T-2, the tests proved to be suitable in the screening of the moldy feed samples for the presence of T-2 toxin and will be able to become the basis of the ELISA test for the quantitative screening kits of T-2 toxin.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.4 no.1
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• pp.34-40
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• 2001

Purpose: The purpose of this study was to evaluate the clinical efficacy of reverse transcription-polymerase chain reaction (RT-PCR) in detecting rotaviral gastroenteritis in children comparing with that of commercial immunoassays. Methods: Stools from 79 children admitted Korea University Hospital due to diarrhea were collected from December 1999 to February 2000. Immunoassays were done using commercial rotavirus Latex kit and Rotatec (ELISA) kit. RT-PCR was performed to amplify group A rotavirus, most commonly pathogenic to human, using VP4- and VP7-specific primers. The detection rates of immunoassays and RT-PCR were compared. Results: ELISA assay was superior to LA assay and moderately concordant with RT-PCR in detecting rotaviral gastroenteritis. Conclusion: Although RT-PCR is known very sensitive, it does not have significant advantage over immunoassay in detecting rotaviral gastroenteritis.

• Korean Journal of Food Science and Technology
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• v.47 no.3
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• pp.401-404
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• 2015

A sandwich ELISA (sELISA) to detect pork in processed foods was developed using goat anti-pig IgG antibodies. From the sELISA standard curve, the detection range of pork was $3-1,000{\mu}g/mL$. The cross-reactivity between the pig IgG antibodies, pork, and other meats (beef, chicken, fish, and crustaceas) was 100, 0.18, and 0%, respectively. When pork was heated for 10 min, the mean assay recoveries of pig-IgG were 79-32% at $60-70^{\circ}C$ and less than 0.11% at $80^{\circ}C$ or higher. When pork was spiked into cream soup, weaning food, fish paste, and sauce, the mean assay recoveries were 8.8, 45, 36, and 39%, respectively. In 12 commercial processed foods, the assay results coincided qualitatively with the food labels on the packages.

• Korean Journal of Veterinary Service
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• v.34 no.2
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• pp.159-166
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• 2011

This study was carried out to develope enzyme-linked immunosorbent assay (ELISA) for detection of canine brucellosis in dogs experimentally inoculated with Brucella abortus 1119-3 and B. canis RM666. Groups A, B and C of dogs (each group consisting of three dogs) were orally inoculated with approximately $5{\times}10^9$ colony-forming units of B. abortus and B. canis, and with sterile pyrogen-free PBS, respectively. The animals were monitored at regular intervals upto the 12th week post inoculation (PI) by standard tube agglutination test (STAT), plate agglutination test (PAT), Rose Bengal test (RBT), 2-mercaptoethanol rapid slide agglutination test (2ME-RSAT) and ELISA. The induced antibody titers in group A dogs were detected from the first week PI to the eighth week PI in STAT, PAT and RBT using the inactivated whole cells of B. abortus 1119-3 as antigens, while no sera in groups B and C dogs reacted with the antigens. In 2ME-RSAT using whole cells of B. canis M-strain as antigens, the induced antibody titers in group B dogs were observed at the second week PI and persisted for the 12th week PI, while sera of groups A and C dogs did not react with the whole cells. In ELISA using cytoplasmic fractions antigen of B. abortus 1119-3, the mean optical density of antibodies in groups A and B was detected from the first and second weeks PI, respectively, and persisted for 12th week PI, while sera of group C did not cross-react with the fractions antigen. However, in ELISA using the hot saline extracts of B. canis M- as an antigen, the induced antibody titers in only group B dogs were detected from second week PI and persisted for until the end of this study. These results indicate that the ELISA using B. abortus 1119-3 cytoplasmic fractions as antigens can be a good candidate for detection of brucellosis by B. abortus as well as B. canis in dogs.