• Parasites, Hosts and Diseases
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• v.55 no.3
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• pp.247-254
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• 2017

ELISA has been used for the diagnosis of toxoplasmosis, but it is being gradually replaced by a rapid diagnostic test (RDT). We compared and analyzed ELISA and RDT results using the sera collected during 4 consecutive years from residents of Gyodong-do (Island), Incheon-city, Korea. Sera from 921, 993, 940, and 838 adult residents were collected on a yearly basis (2010-2013). ELISA was performed by using a crude extract of T. gondii RH strain antigen and IgG/IgM RDT mounted with recombinant fragment of major surface antigen (SAG1), GST-linker-SAG1A, were applied to the sera. Comparison between groups was analyzed by the Student's t-test. The positive seroprevalence surged from 14.7% (135/921, 2010), 23.1% (231/993, 2011), 23.6% (222/940, 2012), and 32.1% (269/838, 2013) by ELISA. In contrast, RDT showed a more moderate increasing trend from 21.7% (200/921, 2010), 25.5% (253/993, 2011), 28.9% (272/940, 2012) and 33.1% (277/838, 2013). Discrepancies between ELISA and RDT were noted near the cut-off value. At the OD 0.15-0.24 range, RDT could detect 16.1% (169/1051) more positives, which suggests an early or acute toxoplasmosis, but at the OD 0.25-0.34 range, ELISA could detect 35.9% (92/256) more positives of possible chronic infections. Over the OD > 0.35 ELISA and RDT agreed in the majority of the cases. This surge in seroprevalence may be caused by the organic agriculture in addition to eating behavior or increase in pets among Koreans. These facts may be applied on a full-scale national survey using RDT to supplement ELISA to define the characteristics of the infection.

• Korean Journal of Food Science and Technology
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• v.36 no.5
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• pp.828-832
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• 2004

Enzyme-linked immune sorbent assay (ELISA) was applied to quantify soy protein in fresh soybean curd (bean curd) produced by combination of genetically modified (GM) and genetically not modified (non-GM) soybeans. Antibodies against 113 and 24 kDa proteins, which appeared only in non-GM bean curd (specific band), and in both non-GM and GM bean curds (non-specific band) based on SDS-PAGE results, were prepared by immunization to rabbit. Through ELISA using either antibody, GM bean curd protein content was determined at dilution rates of $10^{-1}-10^{-6}$. Standard curve showing relationship between ELISA optical density and non-GM protein content was produced using antibody against 113 kDa protein at protein dilution between $10^{-7}\;to\;10^{-6}$, highly antigen content-dependent dilution. Bean curd prepared by random combinations of GM and non-GM soybeans were analyzed by ELISA, and standard curve was produced. Results reveal non-GM protein content of bean curd could be quantified with higher than 93% accuracy.

• Korean Journal of Food Science and Technology
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• v.38 no.2
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• pp.176-182
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• 2006

Sensitive and specific monoclonal antibody (MAb) was produced from hybridoma (1H11-5) obtained by fusion of myeloma cell (V653) and spleen cell isolated from mouse immunized sulfamthazine (SMZ)-HG-KLH. Direct competitive ELISA was developed for rapid detection of SMZ in milk samples using MAb against SMZ with optimized conditions between MAb and SMZ-HG-HRP conjugate, and applicable conditions for analysis of milk samples were established. Detection range of immunoassay was 0.1 to 100 ppb. Recoveries from spiked raw milk and processed milk samples averaged 82.1-120.7 and 82.1-97.1%, respectively.

• Korean Journal of Agricultural Science
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• v.38 no.1
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• pp.45-50
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• 2011

This study was conducted to investigate the farm situation about bovine leukemia virus(BLV) infection that greatly influence productivity in dairy cattle and compare the accuracy of diagnosis for BLV infection between PCR and ELISA techniques. Blood samples of 193 heads from 5 herds in Chungnam and Chungbuk area were used to analyze BLV gene and serum, and the results were obtained as follows. The amplified BLV gene in dairy cattle by PCR technique resulted in 226 bp, 596 bp and 434 bp, respectively, for gag, pol and env, which were well amplified. The infection rates of BLV virus diagnosed by PCR and ELISA techniques ranged from 80.55 to 100% and from 22.22 to 86.95%, respectively, and the infection rates among 5 herds were significantly different in both methods (P<0.05). Further, the average infection rates of 5 herds were 87.05 and 63.21%, respectively, for PCR and ELISA techniques. Kappa statistics for examining consistency of diagnosis by PCR and ELISA techniques showed 0.246, which represents low consistency. Consequently, PCR based BLV technique was considered as a corrective measure for diagnosis of BLV infection in Holstein dairy cattle.

• Journal of Environmental Health Sciences
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• v.34 no.5
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• pp.369-373
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• 2008

The indoor environment is an important source of exposure to various aeroallergens and pathogenic microorganism. It has been shown that exposure to aeroallergens enhances the risk of indoor inhabitants developing asthma. Since the skin prick test, a typical clinical method for identification of subjects positive to allergens, can rarely cause fatal or non-fatal reactions in susceptible persons, an in vitro assay such as ELISA using serum has been considered for testing positivity against various allergens. We evaluated the validity of a serum ELISA kit for screening positive subjects to major aeroallergens including Dermatophagoides farinae, Dermatophagoides pteronyssinus, cockroach, Alternaria, Cladosporium, Aspergillus, Penicillium, dog hair, cat fur, mugwort, and ragweed. The ELISA results were compared with the skin prick test results, and sensitivity, specificity, and overall accuracy were calculated to each allergen. Higher sensitivities were obtained from D. farinae, (77.8%) and D. pteronyssinus (69.2%), but sensitivities to Aspergillus, Penicillium, dog hair, cat fur, and ragweed were very low down to 0%. Specificity ranged from 88.7% (cat fur) to 100% (mugwort and ragweed). Overall the accuracy of the serum ELISA kit was relatively high, in that the lowest was 85.1% for cat fur and the highest was 98.6% for Alternaria, Cladosporium, and ragweed. Considering specificity and overall accuracy for the serum ELISA kit, it may be considered reliable. However, when the kit is used for screening purpose, positivity to aeroallergens should be carefully determined since sensitivity for the kit is low.

• Parasites, Hosts and Diseases
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• v.34 no.4
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• pp.233-238
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• 1996

The seroepidemiologic studies on antral-ToxopIasma antibody titers were carried out using ELISA and indirect latex agglutination test. Among 899 sera prepared from pregnant women, 39 cases (4.3%) revealed positive reaction and 218 sera from middle school students showed 4 positive reaction (1.8%) by ELISA. By LAT (newly established by National Veterinary Research Institute, Korea), the sera of 7 pregnant women (0.8%) showed positive reaction. When 80 sera showing ≥ 1 :8 by LAT were used for comparing the results obtained from LAT and Toxotest-MT (Eikon Chemical Co., Japans, 7 cases and 8 sera were positive, respectively. All of 11 sera of proven toxoplasmosis patients showed positive reaction in both tests. Overall proportion of agreement between LAT kit and Toxotest-MT was 0.94 (K-index : 0.632, p < 0.01), and LAT was considered to be useful for the screening of toxoplasmosis.

• Research in Plant Disease
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• v.18 no.3
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• pp.231-235
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• 2012

Indian citrus ring spot virus (ICRSV) is known to cause a serious disease to citrus, especially to Kinnow mandarin, the popular cultivated citrus species in India. In this study, we developed diagnostic systems based on enzyme-linked immunosorbent assay (ELISA). In order to generate antibodies against ICRSV coat protein, we overexpressed the coat protein in Escherichia coli using the pET15b expression vector containing an optimized ICRSV coat protein gene. The recombinant ICRSV coat protein was overexpressed as soluble form at $37^{\circ}C$ upon IPTG induction. The protein was purified to 95% in purity by Ni-NTA column chromatography. The purified protein was immunized to rabbit for the generation of polyclonal antibody (PAb). The PAb showed a specific immunoreaction to recombinant ICRSV coat protein in western blot analysis and ELISA. Diluted rabbit antisera (10,000 fold) could detect less than 10 ng and 5 ng of the target protein in western blot and ELISA analysis, respectively.

• Journal of Food Hygiene and Safety
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• v.13 no.4
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• pp.419-424
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• 1998

An enzyme-linked immunosorbent assay (ELISA) was established for the detection of zearalenone by using monoclonal antibodies produced by Z-M-26 hybridoma cells when injected into a mouse and zearalenone-oxime-OV A conjugate. Zearalenone-oxime-OV A conjugates were diluted with carbonyl buffer, coated to 96 well microtiter plates at $4^{\circ}C$ overnight and blocked with 1% BSA overnight. One thousand times diluted antibody solution together with standard zearalenone or sample was added to 96-well microtiter plates and stood overnight. A secondary antibody conjugated with HRP was added and an hour later, enzyme substrate (TMBZ) solution was added for color develpment. Mter 30 minutes, coloring reaction was terminated by adding 2 N $H_2S0_4$ and the O.D. was measured at 450 nm. Detection range of this method was about 0.1~100 ppb. The established indirect competitive ELISA method was suitable for a rapid and effective analysis of zearalenone in agricultural products.

• Journal of Microbiology and Biotechnology
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• v.14 no.2
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• pp.256-261
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• 2004

In order to detect chitooligosaccharides (COS) in soybean paste, tandem immunoaffinity chromatography and enzyme-linked immunosorbent assay (ELISA) were developed. Polyclonal anti-chitooligosaccharides mixture (CaSM) antibody specific to COSM was attached to Sepharose gel for initial sample cleanup and concentration of COS in soybean paste. COS was eluted and quantified by competitive direct ELISA (cdELISA). Average ELISA recoveries from the column using binding buffer spiked with COSM at levels of 0.5, 2.0, 5.0, and $10.0\mu$g/ml were 79.8, 72.0, 77.7, and 60.6%, respectively, with a mean recovery of 72.5%. Mean inter-well and inter-assay coefficients of variation (CV) were 7.7% and 10.3%, respectively. Average recoveries from soybean paste spiked with COSM at levels of 2, 6, 20, and $60\mu$g/g were 115, 91.7, 91, and 73.3%, respectively, with a mean recovery of 92.8%. Mean inter-well and inter-assay CV were 12.9% and 16%, respectively. The COS was detected from 24 out of 25 homemade Korean soybean paste samples at an average of $14.0\mu$g/g (n, 25; range, $0-51.2 \mu$g/g) and from 13 out of 14 commercially made soybean paste samples at an average of $4.1\mu$g/g(n, 14; range, $0-18.4\mu$g/g). The tandem immunoaffinity chromatography-cdELISA that was developed in this study showed that the level of COS eluted from homemade soybean paste was higher than that of the commercially made ones. In addition, the level of COS eluted from commercially available soybean paste in Korea was higher than that of the ones in Japan.

• The Journal of Korean Society of Virology
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• v.30 no.2
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• pp.125-130
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• 2000

Infection with human cytomegalovirus (HCMV) is of considerable clinical relevance after placental transmission and in immunosuppressed patients such as transplant recipients or patients with AIDS. The rapid detection method of HCMV has been required to overcome the time-consuming methods such as classical plaque assay or other immunological methods. This study was performed to establish the in situ ELISA, in which human lung fibroblasts infected with HCMV were fixed and used directly as antigen in 96 well culture plate. Expressed HCMV antigens were detected with HCMV-specific monoclonal antibodies. This method could detect HCMV dose-dependently upto $3{\times}10^2\;pfu/ml$. Antiviral activity of ganciclovir could be assayed within the known range of effective dose. This result showed that HCMV could be quantitated by in situ ELISA. The chemical, which was selected on the basis of component analysis in natural product, was tested to have the anti-HCMV activity by in situ ELISA, and three among five samples were found to have anti-HCMV activity with the dose-dependent manner. Conclusively in situ ELISA could be useful method for quantitation of HCMV and screening antiviral activity of samples to HCMV.