• Korean Journal of Veterinary Service
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• v.26 no.1
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• pp.73-80
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• 2003

In order to obtain information on murine model for foot and mouth disease virus(FMDV) type Asia 1, we studied whether guinea pig was a suitable model for studying FMDV. Apparently healthy 3 months old albino guinea pigs and unweaned 3 days old Swiss albino mice were used for this study. Total of 8 guinea pigs were divided into the infected(n=5) and control(n=3) groups. The incubation period of FMDV in the guinea pigs were roughly 2 days and the viremia persisted for 3 days in the guinea pigs. Mice inoculated with the plasma from control guinea pigs did not show any sign of viremia. The plasma were titrated by virus neutralization test using suckling mice as an indicator host. The mean virus neutralizing antibody titers of infected guinea pig at 3 DPI, 4 DPI and 5 DPI were log$\_$10/2.16, log$\_$10/ 3.39 and log$\_$10/ 3.44, respectively whereas there was no neutralizing antibody titer in control group. The difference between the mortality pattern and mean virus neutralizing antibody titer of infected and that of control group at day 3, 4, 5 were statistically significant(p<0.0l).

• Genomics & Informatics
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• v.18 no.3
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• pp.31.1-31.8
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• 2020

The coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has become a global pandemic. No specific therapeutic agents or vaccines for COVID-19 are available, though several antiviral drugs, are under investigation as treatment agents for COVID-19. The use of convalescent plasma transfusion that contain neutralizing antibodies for COVID-19 has become the major focus. This requires mass screening of populations for these antibodies. While several countries started reporting population based antibody rate, its simple point estimate may be misinterpreted without proper estimation of standard error and confidence intervals. In this paper, we review the importance of antibody studies and present the 95% confidence intervals COVID-19 antibody rate for the Korean population using two recently performed antibody tests in Korea. Due to the sparsity of data, the estimation of confidence interval is a big challenge. Thus, we consider several confidence intervals using Asymptotic, Exact and Bayesian estimation methods. In this article, we found that the Wald method gives the narrowest interval among all Asymptotic methods whereas mid p-value gives the narrowest among all Exact methods and Jeffrey's method gives the narrowest from Bayesian method. The most conservative 95% confidence interval estimation shows that as of 00:00 on September 15, 2020, at least 32,602 people were infected but not confirmed in Korea.

• Korean Journal of Veterinary Research
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• v.61 no.3
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• pp.23.1-23.8
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• 2021

Porcine epidemic diarrhea (PED) is characterized by acute enteritis, watery diarrhea, weight loss, dehydration, and death with high mortality in neonatal piglets. In this study, 3 virus isolates collected in Vietnam between 2016 and 2017 were successfully propagated in Vero cells at high virus titers. Sequence analysis of the full-length spike (S) gene revealed that all 3 isolates belong to genogroup 2a, which is closely related to other prevalent Asian strains. Amino acid sequence comparisons revealed 98.19% to 99.13% homology with the Vietnam isolates circulating during 2013-2015, suggesting that field PED viruses (PEDVs) evolve continuously. Experiments in animals demonstrated that antisera from guinea pigs immunized with the vaccine strain resulted in higher levels (5 log₂) of neutralizing antibody against the homologous strain, and showed a relatively lower level of neutralizing antibody against the field isolates. This finding would be helpful in choosing a PEDV strain for vaccine development.

• Korean Journal of Veterinary Research
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• v.28 no.2
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• pp.355-359
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• 1988

A porcine parvovirus inactivated vaccine was prepared and inoculated to 7 piglets and also 8 guinea-pigs, and their serum antibodies were titrated. Twenty-two field serum samples of unvaccinated sows were also tested by SN and HI methods. It was observed that SN test was superior over HI test. Therefore, it is suggested that the SN test could well be used in the detection of serum antibody for PPV in vaccinated pigs.

• Clinical and Experimental Vaccine Research
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• v.12 no.4
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• pp.337-345
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• 2023

Purpose: The global fight against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has led to widespread vaccination efforts, yet the optimal dosing schedule for SARS-CoV-2 vaccines remains a subject of ongoing research. This study aims to investigate the effectiveness of administering two booster doses as the third and fourth doses at different intervals to enhance vaccine protection. Materials and Methods: This study was conducted at a military regional hospital operated by the Ministry of National Defense in Taiwan. A cohort of vaccinated individuals was selected, and their vaccine potency was assessed at various time intervals following their initial vaccine administration. The study participants received booster doses as the third and fourth doses, with differing time intervals between them. The study monitored neutralizing antibody titers and other relevant parameters to assess vaccine efficacy. Results: Our findings revealed that the potency of the SARS-CoV-2 vaccine exhibited a significant decline 80 days after the initial vaccine administration. However, a longer interval of 175 days between booster injections resulted in significantly higher neutralizing antibody titers. The individuals who received the extended interval boosters exhibited a more robust immune response, suggesting that a vaccine schedule with a 175-day interval between injections may provide superior protection against SARS-CoV-2. Conclusion: This study underscores the importance of optimizing vaccine booster dosing schedules to maximize protection against SARS-CoV-2. The results indicate that a longer interval of 175 days between the third and fourth doses of the vaccine can significantly enhance the neutralizing antibody response, potentially offering improved protection against the virus. These findings have important implications for vaccine distribution and administration strategies in the ongoing battle against the SARS-CoV-2 pandemic. Further research and largescale trials are needed to confirm and extend these findings for broader public health implications.

• Journal of Microbiology and Biotechnology
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• v.28 no.8
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• pp.1376-1383
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• 2018

The hepatitis B virus (HBV) envelope contains small (S), middle (M), and large (L) proteins. PreS1 of the L protein contains a receptor-binding motif crucial for HBV infection. This motif is highly conserved among 10 HBV genotypes (A-J), making it a potential target for the prevention of HBV infection. In this study, we successfully generated a neutralizing human monoclonal antibody (mAb), 1A8 (IgG1), that recognizes the receptor-binding motif of preS1 using a phage-displayed human synthetic Fab library. Analysis of the antigen-binding activity of 1A8 for different genotypes indicated that it can specifically bind to the preS1 of major HBV genotypes (A-D). Based on Bio-Layer interferometry, the affinity ($K_D$) of 1A8 for the preS1 of genotype C was 3.55 nM. 1A8 immunoprecipitated the hepatitis B virions of genotypes C and D. In an in vitro neutralization assay using HepG2 cells overexpressing the cellular receptor sodium taurocholate cotransporting polypeptide, 1A8 effectively neutralized HBV infection with genotype D. Taken together, the results suggest that 1A8 may neutralize the four HBV genotypes. Considering that genotypes A-D are most prevalent, 1A8 may be a neutralizing human mAb with promising potential in the prevention and treatment of HBV infection.

• Journal of fish pathology
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• v.22 no.3
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• pp.219-228
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• 2009

The genomic and subgenomic RNAs of fish nodavirus encode the four proteins, protein A, capsid protein, non-structural protein B1 and B2. In this study, we describe the immune response of olive flounder Paralichthys olivaceus immunized with live fish nodavirus or recombinant capsid protein, non-structural protein B1 and B2 expressed in E. coli. Nodavirus-infected flounder produced antibodies to capsid protein, B1 and B2 and nodavirus-neutralizing activities were detected in the serum of the nodavirus-infected flounder. The flounder were immunized against the three recombinant proteins of fish nodavirus and the sera from these immunized fishes were assayed for nodavirus-specific antibody by ELISA and a neutralization test. In the immunized flounder, all three recombinant proteins induced the production of similar levels of antibody, but only the antibody to capsid protein significantly neutralized nodavirus. These results indicate that all three nodaviral proteins are immunogenic in flounder, but only the capsid protein can induce neutralizing antibody against nodavirus.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.165-169
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• 1999

The incidence of aseptic meningitis infection is ensuing and threatening the health of children. Enteroviruses are the major agents of aseptic meningitis and identification of virus has been a clue to diagnosis and epidemiology. The outbreak of aseptic meningitis occurred in Pusan, 1998. Patients were concentrated from April through November. Children were more susceptible than adults. Among 306 cases of specimens from stool, throat swab tested, only 7.2% were positive on virus isolation, 12 cases from stool and 10 from throat, respectively. All isolated 7 serotypes of viruses represented cytopathic effect on cultured cells. Three types of echovirus 6.25, 30 and coxsackievirus B2, B3, B4, B6 were identified by neutralizing antibody test. Isolated coxsackievirus and echovirus were observed by an electron microscope with negative staining.

• Korean Journal of Veterinary Research
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• v.29 no.2
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• pp.83-90
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• 1989

The changes in serum total protein and immunoglobulin levels, and BVD, IBR and PI-3 viral neutralizing antibody titers in colostrum-conferred Korean native calves during the first 12 weeks postpartum were studied, and the results obtained were summerized as follows: The Mean concentration of total protein, total immunoglobulin, IgG, IgM and IgA in sera of 9 calves at birth were $3.8{\pm}0.5g/dl$, $0.27{\pm}0.15mg/ml$, $0.06{\pm}0.08mg/ml$, $0.21{\pm}0.11mg/ml$, and extremely low concentration, respectively. Serum total protein level reached a maximum at 20 hours after birth, total immunoglobulin, IgG, and IgM levels at 24 hours, and IgA level at 28 hours, respectively. Serum IgA level reached a minimum at 4 weeks old, IgM level at 5 weeks, total immunoglobulin level at 8 weeks, and IgG level at 10 weeks, respectively. After then those levels had begun to increase, but total protein level was still decreasing at 12 weeks old. The half-lives of IgG, IgM, and IgA were 21.1 days, 4.0 days, and 2.6 days-respectively. In 10 Korean native cows immediately after parturition, serum neutralizing antibody titers specific to BVD, IBR and PI-3 virus were $8.7{\pm}1.5{\log}_2$, $5.7{\pm}1.2{\log}_2$, and $6.8{\pm}1.01{\log}_2$, respectively. And colostral neutralizing antibody titers against BVD, IBR, and PI-3 virus were $10.1{\pm}1.4{\log}_2$, $6.8{\pm}1.3{\log}_2$ and $7.8{\pm}1.7{\log}_2$, respectively. Before suckling the colostrum, SN antibody titers against BVD, IBR, and PI-3 virus were undetectable from all of 9 Korean native calves. Nevertheless SN antibody titer against BVD virus reached a maximum level ($9.2{\pm}0.6{\log}_2$) at 24 hours after birth, that against IBR virus ($6.1{\pm}1.0{\log}_2$) at 20 hours after birth, and that against PI-3 virus ($6.8{\pm}0.9{\log}_2$) at 32 hours after birth, respectively. In 12 weeks old calves, the SN antibodies against BVD and IBR virus were still decreasing, but that against PI-3 virus reached a minimum at 10 weeks, and increased after 12 weeks of age. The half-lives of SN antibodies against BVD, PI-3 and IBR, virus were 16.0 days, 22.6 days, and 25.5 days, respectively.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1994.11a
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• pp.61-67
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• 1994

One fundamental problem in developing an AIDS vaccine is antigenic variation of HIV. Despite a substantial induced immune response in gp120-immunized monkeys and humans, high titers of V3-directed type specific neutralizing antibodies may not be sufficient to neutralize continuously emerging new isolates. Several studies analyzing anti-gp120 antibodies in HIV-infected individuals have clearly indicated that most broadly neutralizing antibodies are directed to conformation-dependent epitopes. Therefore, it seems important to evaluate the potential efficacy of candidate gp120 vaccines at inducing such antibodies, that might be potentially protective against multiple HIV strains. One concern in the development of any recombinant protein as a vaccine is its stability when mixed with an adjuvant. This could be a particularly important factor for recombinant gp120, given the conformational nature of its major, broadly neutralizing, epitopes. We hypothesized that gp120 complexed with recombinant CD4 could stabilize the conformation-dependent epitopes and effectively deliver these epitopes to the immune system. In this study, a soluble gp120-CD4 complex in Syntex Adjuvant Formulation was tested in mice to analyze the anti-gp120 antibody response. With the aim of defining the fine specificity and neutalizing activities of the immune response, 17Mabs were generated and characterized. The studies indicate that the gp120-CD4 complex elicits neutralizing anti-gp120 antibodies, most of which are directed to the conformation dependent epitopes.