• Korean Journal of Veterinary Research
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• v.46 no.3
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• pp.185-196
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• 2006

Newcastle disease (ND) is a highly contagious disease of poultry that can cause severe economic losses throughout the world. Vaccination has been used for a long time and proved as one of the most effective method to reduce the economic loss due to ND virus infection, The measurement of antibody titer such as hamagglutination-inhibition (Hl) test with sera has been used as a useful method to evaluate the immunity leve of host. However, Hl test is gradually being replaced by the enzyme linked-immunosorbent assay (ELISA), To evaluate the efficacy of ELISA in the chickens vaccinated with different procedure, present study has been performed. After SPF chicks and commercial broilers were vaccinated with different kinds of live vaccines such as V4, VG/GA and/or Bl at various time, the antibody level has been measured using both HI test and ELISA. Challenge test with velogenic viscerotropic NDV was also performed to measure the protective level of antibody. In the SPF chickens, the mean ELISA titer after vaccination and survival rate after challenge was increased and correlated with days post inoculation. More than 80% of chickens with higher than 1,000 ELISA titer after vaccination were survived after challenge with velogenic ND virus and had good correlation between survival rate and antibody titier. In commercial broiler chickens, most of them at market age had low level of ELISA titer regardless of the number of vaccination, and had a low correlation between survival rate and ELISA titer. However, the ELISA titer of remaining birds after challenge was increased. This result indicated that ELISA titer had good response against velogenic NOV infection compared to Hl titer.

• Korean Journal of Veterinary Service
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• v.26 no.3
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• pp.215-219
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• 2003

This study was conducted to investigate the similarity between hemagglutination inhibition (HI) test and enzyme-linked immunosorbent assay(ELISA) titers and sample to positive ratio (S/P ratio) of Newcastle disease(ND) virus. To perform this study, the 372 sera of broiler chicks and 120 sera of layers and breed chicks were collected from slaughter house and farms, respectively. As a result of HI test out of different chicks, the positive percentage of ND antibody titer of broiler, layer and breeder, when a standard positive HI titer were '2', was 84.4%, 100% and 100%, respectively. The positive percentage of ND antibody titer by ELISA was shown 38.4%, 100% and 100% and S/P ratio were also shown 81.5%, 98.2% and 99.2%, respectively. The results of comparative survey with same sera by two experimental methods were as follows; In low HI titer, ELISA titer was not similar to HI titer, but S/P ratio was similar to it. In high HI titer, ELISA titer was not similar to HI titer. Therefore, HI titer was more similar to S/P ratio than ELISA titer.

• Journal of Environmental Health Sciences
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• v.23 no.4
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• pp.73-81
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• 1997

Diphtheria was the world-spread, respiratory infectious disease in the past. But after developing the diphtheria toxoid, diphtheria vaccine, composed of diphtheria toxoid, is generalized, so prevalence of diphtheria is sharply dropped. But diphtheria is come back in NIS(New Independent States) in 1990s. It is believed that recurrence of diphtheria is mainly due to shortage of protective diphtheria antibody titer in adults. And it is related to 70% prevalence in adults, not in children. Considering this changing environment, this study was designed to research the diphtheria antibody titer of whole population and existence of titer difference by sex. Also it was studied whether ELISA has fitness as determination method of diphtheria antibody titer compared with neutralization method on microcell culture. This study was done to 277 samples of three hospitals in Seoul area, and sera was tested by neutralization method on microcell culture and ELISA method. The results of this study were as follows 1) Of this studied population, 31.05% had an antibody titer below the protective level (<0.01 IU/ml), 40.79% had a titer of a relative degree of protection (0.01-0.09 IU/ml) and 28.16% had a reliable degree of protection ($\geq$0.1 IU/ml). Therefore, 68.95% had a basic protective antibody titer level. 2) 20-40 age group showed the lowest diphtheria antibody titer among the studied population. 3) GMT of diphtheria antibody titer was the highest in the children. But, after child period, GMT was fallen. Standard deviation value was the lowest in older group. 4) Protective level of diphtheria antibody titer of male was slightly higher than female (70.94% vs 66.66%). But this difference was not statistically significant. 5) Diphtheria antibody titer by ELISA method was wholly higher than by neutralization method on microcell culture. Compared the two results by ELISA and neutralization, the regression coefficient was 0.38. And in titer, which was obtained by ELISA method, false-positive results was abundant.

• The Journal of the Korean Society for Microbiology
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• v.21 no.2
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• pp.205-210
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• 1986

Serological investigations for the leptospirosis on hospitalized patients in Choonchun Sungsim Hospital during the periods from August to November 1985 and 841 inhabitants of Kangwondo area including Choonchun, Choonsung, Inje, Chulwon, Hwachun, Gosung, Taibaik, Samchuk and Yangju area were carried out. 1. Among 58 hospitalized patients who were suspected as leptospirosis, 10 patients were detected to have antibody against Leptospira. All of positive sera had the highest antibody titer against serogroup Icterohemorrhagiae and most positive sera were also reactive to serogroup Australis and Canicola. Antibody titer of positive sera detected by microscopic agglutination(MA) test were ranging from 1 : 40 to 1 : 2,560. Antibody titer detected by ELISA method were higher than those detected by MAT(ELISA 1 : 400$\sim$1 : 25,600) and IgM titer of positive sera were generally higher than IgG titer. 2, Of 841 inhabitants in 8 area of Kangwondo, 17 persons (2,02%) possessing antibody against Leptospira were detected by ELISA method, IgG titer in positive sera were generally higher than IgM titer. Persons possessing antibody to Leptospira were distributed in both sex and in various age group, and no significant regional and occupational fluctuations were obserbed.

• Korean Journal of Veterinary Service
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• v.21 no.3
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• pp.277-284
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• 1998

Serum samples were collected from 100 breeders and their progeny 600 broilers. The breeders and broilers were vaccinated against infectious bronchitis(IB), infectious bursal disease(IBD) and Newcastle disease(ND) viruses according to general vaccination program. The antibodies in serum samples against IB, IBD and ND viruses were detected by ELISA using commercial ELISA kit. Geometric mean titer(GMT) of ELISA was monitored from 1-day-old to 35-day-old broilers and compared to that of breeder chickens. The GMT of ELISA to IB, IBD and ND was declined half level of the day old broiler's antibody titers at about 4, 9 and 4 days of age. The GMT of ELISA to IB, IBD and ND was declined than that of protective antibody titer at about 12, 11, and 15 days of age. Thereafter, the GMT of ELISA to IB, ND were declined and disappeared according to age of broilers. The GMT of ELISA to IBD was declined according to age of broilers, but at 25 days of age increased and 31 days of age increased than that of protective antibody titer. Taken together, these studies led to conclusion that time-course of antibody titers of broilers from vaccinated breeders and that of progeny broliers which vaccinated according to vaccine program. Those are very important data to design vaccine program to breeders and broilers.

• Korean Journal of Veterinary Research
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• v.29 no.4
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• pp.503-515
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• 1989

Critical parameters affecting sensitivity and specificity of an enzyme-linked immunosorbent assay(ELISA) for detection of antibodies to avian infections bronchitis virus(IBV) were standardized. By adopting the optimized conditions an equation calculating ELISA antibody titers from the observations at single serum dilution was formulated. The purified antigen of IBV Mass-41 strain was dispensed into polystyrene microplate wells at a concentration of 300ng per well($100{\mu}l$) and the plates were coated by completey drying at $37^{\circ}C$. Diluted chicken serum and horseradish peroxidase conjugated goat anti-chicken IgG were added in order in $100{\mu}l$ volumes per well and allowed to react for 30 minutes each at room temperature. Just before use and after each reaction the plates were washed three times with distilled water. Finally o-phenylenediamine solution was added as an enzyme substrate. After incubation for another 15 minutes at room temperature absorbances were read at 492nm. Hyperimmune serum against Mass-41 strain was used as internal reference positive(IRP) serum. After repeated titration of IRP and negative serum, a constant titer of IRP was determined. Serum titrations were carried out for various sample sera together with IRP and negative sera and the observed titers of sample sera were corrected by reflecting the ratio between observed and constant titers of IRP serum. These corrected titers of the sample sera were plotted against sample/positive(S/P) OD ratios. All the OD's measured in the serum titrations were also corrected by substracting negative serum OD. The following equation was formulated from the above data; $Log_{10}$ ELISA titer=$5.568({\log}_{10}S/P)+4.161$ Thus it was possible to calculate ELISA titer by measuring absorbance at 1/400 single serum dilution. Titer measured by cross ELISA tests employing Mass-41 strain and three local IBV isolates were similar. These results suggest that the ELISA tests standardized in this study can be used for evaluating not only vaccinal immunity but also for infection status against fields IBV's.

• Parasites, Hosts and Diseases
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• v.30 no.2
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• pp.83-90
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• 1992

Sensitivity of anti-Texoplasma antibody (IgG) test by enzyme·linked immunosorbent assay (ELISA) was evaluated in comparison with indirect laten agglutination (ILA) using 2,016 paired human samples of serum and cerebrospinal quid (CSF) . The samples were collected from neurologic patients in Korea with mass lesions in central nervous system(CNS) as revealed by imaging diagnosis(CTIMRI). When the sera were screened for anti-Toxoplasma antibody by ILA, 76 cases (3.8%) were positive (1:32 or higher titers). In the pairs samples of CSF, no positive reactions were observed. When ELISA was performed using PBS extract of Percoll purified tachysoites as antigen, cut-off absorbance was determined as 0.40 for serum and 0.27 for CSF tests. The antibody positive rates by ELISA were 7.0% in serum and 5.6% in CSF Of them, 40 cases(2.0%) showed positive reactions in both serum and CSF, The antibody positive rates were higher in groups older than 40 years, The rates were higher in male(4.7% by ILA, 8.3% by ELISA) than in female(2.2% by ILA, 5.0% by ELISA). The rates in CSF showed no such sex difference. ELISA showed twice higher positive rates when serum was tested, and was sensitive enough to detect specific antibodies in CSF. Etiologic relations between positive antibody tests and CNS lesions remained unknown.

• Journal of the Korea Institute of Military Science and Technology
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• v.13 no.3
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• pp.478-485
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• 2010

The vaccine is biological pretreatment that improves immunity to a particular disease. We can get immunity from producing antibody with injection antigen which has ability to defense against the disease. The ELISA is the most widely used method to measure antibody titer. We have developed and performed validation of ELISA according to the guideline of KFDA and ICH. In this paper, we have verified ELISA method is an excellent method to measure the titer of anti-PA antibody. We have constructed recombinant protective antigen among anthrax toxins and used as antigen of ELISA. In this validation, we have evaluated precision (repeatability, interlaboratory precision), specificity, linearity(range) and LOD, which are validation articles suggested by guideline. Inter-person precision was replaced with inter-laboratory precision. From the results, we have confirmed high precision in all experiments with CV under 20%.

• Parasites, Hosts and Diseases
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• v.25 no.2
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• pp.188-194
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• 1987

The development of antibody titers and crossreaction between Sarcocystis and Toxoplasma were investigated by means of IF A test and ELISA in pigs experimentally infected with $1.5{\times}10^6$ S. suicanis sporocysts and 10,000 T. gondii oocysts, respectively. The intact and soluble Sarcocystis antigens were prepared from the bradyzoites harvested by peptic digestion of infected pork. The intact and soluble Toxoplasma antigens were prepared from the tachyzoites in mouse peritoneal cavity. IgG antibodies in pigs infected with Sarcocystis and Toxoplasma, respectively were detected first at 2 weeks post infection on both IF A test and ELISA. The antibody titer to Toxoplasma reached its maximum at 6 weeks post infection and decreased thereafter. The antibody titer to Sarcocystis reached its maximum terminally. The cross-reaction titer in pigs infected with Toxoplasma against Sarcocystis antigen was up to 1 : 16 in IFA test and up to 1 : 32 in ELISA. The titer in control group was below 1 : 4 in both reactions.

• Korean Journal of Veterinary Service
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• v.21 no.2
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• pp.133-139
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• 1998

Serum samples collected from 30 breeders and their progeny 30 chicks. The antibodies against infectious bronchitis(IB), infectious bursal disease (IBD) and Newcastle disease(ND) viruses were detected by ELISA using commercial ELISA kit. The breeders were vaccinated against IB, IBD and ND viruses according to general vaccination program. Geometric mean titers(GMT) of ELISA were monitored from 1-day old to 17-day old chicks and compared with breeder chickens. The GMT of ELISA to IB, IBD and ND were declined half level of the breeder antibody titer at 6-, 8- and 7-day old. And, the GMT of ELISA to IB, IBD and ND were declined than that of protective titer at 6-, 1-, and 4-day old. Thereafter, the GMT of ELISA was declined and disappeared according to ages of chicks. Taken together, this study led to conclusion that time-course of maternal antibody titers of chicks from vaccinated breeders, and this is very important data for vaccination to chicks.