• Journal of Food Hygiene and Safety
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• v.13 no.3
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• pp.206-212
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• 1998

An improved antibody-coated sensor system based on quartz crystal microbalance was developed for the detection of Salmonella spp. An antibody against Salmonella common structural antigen was immobilized onto one gold electrode of the piezoelectric quartz crystal surface by various immobilization procedures. The best results in sensitivity and stability were obtained with the thin layers of protein A and 3,3'-dithiopropionimidate.2HCI(DTBP), a homobifunctional thiol-cleavable crosslinker. After the addition of a S. typhimurium suspension into a reaction cell with 0.1 M sodium phosphate buffer, pH 7.2, the resonant frequency owing to S. typhimurium adsorption decreased conspicuously. The antibody-immobilized crystals prepared by the gold-protein A complex formation and DTBP thiolation showed the frequency shifts of 80 and 283 Hz, respectively. The time required for maximum frequency shift was about 30~60 min. The antibody-coated crystal could be reused for 6~8 consecutive assays.

• Korean Journal of Veterinary Service
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• v.22 no.4
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• pp.371-375
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• 1999

Total 1,434 sera collected from 72 pig farms were tested for the detection of porcine reproductive and respiratory syndrome (PRRS) virus antibodies. The overall seroprevalence of PRRS virus antibodies was 49.3% (707/727). Of 72 farms tested 59 (81.9%) farms had at least one or more than one pigs with PRRS virus antibodies. The seroprevalence of PRRS virus antibody varied with age. Seroprevalence of PRRS virus antibody in 1 to 30-day-old, 31 to 40-day-old, 41 to 50-day-old, 51 to 60-day-old, and over 61-day-old pig were 27.4%, 52.3%, 57.9%, 52.7%, and 68.2%, respectively. Gilt showed relatively higher seroprevalence (61.2%) than sow (29.2%) and boar (38.3%). In most farms, the infection of PRRS virus was chronic and confined to grower or finisher. This pattern of infection suggests that partial depopulation of the infected herds appears be one of the measures to eradicate the PRRS virus infection. High seroprevalence of the PRRS virus antibody in gilts and boars indicates that the infected gilts and boars in the breeding farms are the major source of the PRRS virus infection, and also play an important role in spreading the PRRS virus between fan mates or herds.

• Parasites, Hosts and Diseases
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• v.25 no.1
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• pp.7-12
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• 1987

The indirect fluorescent antibody(IFA) test was used to detect serum IgG and IgM antibodies to Trichomonas vaginalis in 31 vaginal trichomoniasis, 7 candidiasis and in 20 non-infected healthy women with antigen prepared from axonic culture of Trichomenas vaginalis isolated from vulvovaginitis patient. The results were as follows: 1. In 31 vaginal trichomoniasis the positive reactions of IgG antibody were 27 in the 1/8 dilution or higher and :l in the 1/4 dilution whereas in healthy women the reaction showed significantly low as in the 1/4 dilution or below. 2. The sensitivity and specificity of IFA test for IgG antibody to trichomonad antigen in this study were 87.1% and 100%, respectively. 3. No significant difference of IgM antibody levels between vaginal trichomoniasis and healthy women was observed. 4. No relation between the levels of IgG and IsM antibodies to trichomonad antigen by IFA test was observed. 5. No relation between the time lapse and the level of serum IgG antibodies in IFA test of vaginal trichomoniasis was regarded. In conclusion the present study suggests that IFA test in trichomoniasis could be a useful tool for detection of anti-trichomonad IgG antibodies and applicable as an immunodiagnostic method.

• Bulletin of the Korean Chemical Society
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• v.32 no.6
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• pp.1975-1979
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• 2011

The modification of a gas diffusion layer (GDL), a vital component in polymer electrolyte fuel cells, is described here for use in the electrochemical detection of antibody-antigen biosensors. Compared to other substrates (gold foil and graphite), mouse anti-rHBsAg monoclonal antibody immobilized on gold-coated GDL (G-GDL) detected analytes of goat anti-mouse IgG antibody-ALP using a relatively low potential (-0.0021 V vs. Ag/AgCl 3 M NaCl), indicating that undesired by-reactions during electrochemical sensing should be avoided with G-GDL. The dependency of the signal against the concentration of analytes was observed, demonstrating the possibility of quantitative electrochemical biosensors based on G-GDL substrates. When a sandwich method was employed, target antigens of rHBsAg with a concentration as low as 500 ng/mL were clearly measured. The detection limit of rHBsAg was significantly improved to 10 ng/mL when higher concentrations of the 4-aminophenylphosphate monosodium salt (APP) acting on substrates were used for generating a redox-active product. Additionally, it was shown that a BSA blocking layer was essential in improving the detection limit in the G-GDL biosensor.

• Journal of Biosystems Engineering
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• v.31 no.2 s.115
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• pp.128-134
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• 2006

Frequent outbreaks of foodborne illness demand the need for rapid and sensitive methods for detection of these pathogens. Recent development of biosensor technology has a great potential to meet the need for rapid and sensitive pathogens detection from foods. An antibody-based fiber-optic biosensor and an automated reagents supply system to detect Listeria monocytogenes were developed. The biosensor for detection of Listeria monocytogenes in PBS and bacteria spiked food samples was evaluated. The automated reagents supply system eliminated cumbersome sample and detection antibody injection procedures that had been done manually. The biosensor could detect $10^4$ cfu/ml of Listeria monocytogenes in PBS. By using the fiber-optic biosensor, $2x10^8$ cfu/ml of Listeria monocytogenes in the food samples were detectable.

• Korean Journal of Veterinary Research
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• v.45 no.2
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• pp.191-197
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• 2005

An immunochromatographic (IC) strip for the rapid detection of Salmonella spp. in the enriched sample was developed. Affinity purified Salmonella polyclonal antibody was conjugated with 40 nm colloidal gold particles which were prepared by citrate method in our laboratory. The antigen-antibody-gold complex was captured by Salmonella antibody attached to test line of nitrocellulose membrane during the capillary migration of sample. Specificity of the IC strip was calculated to be 100% (12/12) and sensitivity was 97.6% (41/42) in the test with pure cultured bacteria. Salmonella was artificially inoculated into raw pork macerated with enrichment broth. And then it was 10-fold diluted from $5.2{\times}10^{8}CFU/ml$ to 5.2 CFU/ml. The IC strip could detect $5.2{\times}10^{6}CFU/ml$ before enrichment. However, the lowest limit of detection was 5.2 CFU/ml after overnight incubation. The results indicated that the IC assay was a rapid, economical and simple method with high specificity and sensitivity for the detection of Salmonella spp. without using any equipment.

• Korean Journal of Veterinary Research
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• v.40 no.1
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• pp.81-85
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• 2000

Coxiella burnetii (C burnetii) is the causative agent of Q fever in animal and human. The distribution of the disease has been documented around world. In this study we developed the competitive enzyme linked immunosorbent assay(cELISA) and compared it with indirect immunofluorescent assay(IFA). A monoclonal antibody(Mab) against C burnetii and a peroxidase-conjugated anti-mouse IgM were used as an indicator system competing against antibody in animal serum or as an indicater of the absence of antibody. Sera were considered antibody positive when the percentage inhibition index(PI index) is upper than 30. PI index is calculated as 100-[sample OD/Mab OD)${\times}100$]. Among 162 bovine serum samples, 23 samples were antibody positive both in cELISA and IFA. And 156 samples showed same results. From goat with experimentally induced infection with C burnetii the antibody was detected 20 days early in cELISA compared to IFA. On the basis of present findings, it was demonstrated that cELISA is a reliable diagnostic method for The detection of specific antibodies against C burnetii infection.

• KSBB Journal
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• v.11 no.4
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• pp.420-430
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• 1996

One-step immuno-chromatography assay system for heat-killed Salmonella typhimurium antigens was developed. Three major components used were a glass fiber membrane (placed at the bottom of the system) with an antibody (specific to the analyse, detection antibody)-gold conjugate deposited in a dry state on the surface, a nitrocellulose membrane (middle) with an antibody (also, specific to the analyse but recognized different epitome: capture antibody) and anti-detection antibody immobilized in spatially separated areas, and a cellulose membrane (top) as absorption pad. These membranes were partially superimposed such that a wicking of aqueous solution containing sample can continuously take place through membranes. Variables that affected the system performance were the concentration of capture antibody, the location on the membrane, inert protein used for blocking of the membrane and for carrying the sample, and the concentration of the gold conjugate. Under optimal conditions, within 15 minutes after absorption of a sample solution from the bottom of the system antigen-antibody complexes of sandwich type were formed on the membrane surface area with immobilized capture antibody and a color signal was generated in proportion to the analyse concentration. The minimum do tection limit of the analyse was $1{\times}106$ Salmonella cells/mL.

• Korean Journal of Veterinary Research
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• v.10 no.2
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• pp.53-57
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• 1970

Hog cholera (HC) virus detection from the artificially infected pigs was made using fluoreescent antibody technique (FAT) and END method. It was observed that the swine origin virulent was detected in most of the organs tested at the early stage of the infection, while the tissue culture attenuated virus was detected only in blood (transitionally), lung, and tonsil.

• Korean Journal of Veterinary Service
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• v.19 no.1
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• pp.30-38
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• 1996

Enzyme-linked immunosorbent assay (ELISA) was developed to detect rotavirus antigen in fecal samples using VP6-specific monoclonal antibody(2B12). The ELISA for rotavirus antigen detection found to have specificity to all bovine and porcine rotaviruses tested but not to bovine viral diarrhea virus and bovine coronavirus. The ELISA appeared to have similar sensitivity and specificity compared to fluorescence antibody assay(FA) and electropherotyping (PAGE).