• Journal of Microbiology and Biotechnology
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• v.14 no.4
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• pp.745-750
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• 2004

The objective of this collaborative study was to establish a Korean standard of Japanese encephalitis (JE) vaccine (mouse brain-derived, formalin-inactivated) for potency assay. A candidate preparation proposed as a Korean standard was provided by GreenCross Vaccine, and six laboratories, including one national control laboratory and five manufacturers of JE vaccine, participated in the study. The potency of the candidate preparation and a reference standard obtained from Japan was estimated by mouse immunogenicity assay using the in vitro plaque reduction neutralization test (PRNT). The results of 72 assays conducted by the 6 laboratories showed that the overall mean potency estimate of the candidate preparation was 2.455 log median plaque reduction neutralization antibody titer per 0.5-ml dosage administered twice in mice at 7-day intervals, and that the mean potency ratio of the candidate preparation relative to the reference standard was 1.074. The potency estimates were quite variable among laboratories irrespective of the preparation. The variability of assays assessed by Z scores and coefficient of variation (CV) were in general within the level of acceptance (Z scores within $\pm3$ and $CV\;\leq\;15%$). Therefore, we concluded that the candidate preparation would be suitable as a national standard for testing the potency of JE vaccine (inactivated).

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.3
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• pp.230-235
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• 2005

For the acellular pertussis vaccine with a high immunogenicity, the concentration, composition and characteristics of acellular pertussis antigens are the crucial points to be considered. Nevertheless, it has not been proved yet whether or not the polymerization degree, one of the characteristics of formalin-detoxified acellular pertussis antigens, has an influence on vaccine potency. Thus, in the present study, the correlations among detoxification conditions of acellular pertussis bulks, their polymerization degrees and their immunogenicities were examined. In addition, the relative importance of pertussis toxoid in vaccine immunogenicity was also investigated. Results show that a lower lysine concentration during detoxification induces highly-polymerized antigens, the immunogenicity has a great dependency on the polymerization degree of antigens, and also pertussis toxoid has a relatively stronger influence on the immunogenicity than other antigens. Accordingly, in the aspect of the potency of detoxified acellular pertussis vaccine, it can be demonstrated that the polymerization of antigens and its degree are the major factors affecting the immunogenicity along with a relatively high content of pertussis toxoid

• Korean Journal of Veterinary Research
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• v.56 no.3
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• pp.189-192
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• 2016

The virus neutralization (VN) test was used to determine potency of the infectious bronchitis (IB) vaccine. The results of VN, hemagglutination inhibition (HI), and enzyme-linked immunosorbent assay (ELISA) were compared with those of the IBV M41. The $r^2$ values between VN and HI titers and the ELISA antibody titer were 0.8782 and 0.0336, respectively, indicating a high correlation between VN and HI, but not VN and ELISA. The Cohen's kappa coefficient between the VN titer of 2 $log_{10}$ and HI titer of 5 $log_2$ was 0.909. Our results showed that VN could be replaced with HI for testing the potency of IBV M41.

• Korean Journal of Veterinary Research
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• v.49 no.3
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• pp.201-205
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• 2009

In this study, we evaluated the stability and potency of live attenuated rinderpest vaccines of lapinized-avianized tissue culture strain origin, which had been produced annually from 2005 to 2008. When immune responses to the vaccines were evaluated using two Holstein calves weighing 100~150 kg, neutralizing antibody titer of 1 : 16 was induced at 21 days post vaccination. When calves were also inoculated with vaccines lots that had been stored for 39 months at ${4^{\circ}C}$, same level of antibody titer was observed. Using the virus titer test, we found that all batches of the vaccine that had been kept for 3, 10, 15, 22, 27, 34, 39, and 45 months showed no significant loss of titers, and fulfilled the requirement necessary ($\geq$ 3 $logTCID_50$) to be used as the national rinderpest vaccine reserve in Korea. In this study, we demonstrated that stability and potency of the rinderpest vaccines were maintained over three years when kept at ${4^{\circ}C}$ storage. This indicates that it maybe feasible to extend the expiration period of this vaccine from one year to three years.

• Korean Journal of Veterinary Research
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• v.45 no.2
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• pp.215-221
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• 2005

Canine coronavirus (CCV) causes a mild gastroenteritis in dogs. The virus is highly contagious. Although the virus was isolated more than thirty years ago, canine coronavirus infection continues to be a widespread problem. Mixed infections with both CCV and canine parvovirus (CPV) are common. Four kinds of commercial killed CCV vaccines are available in Korea. All the commercial vaccines should pass the National Assay for Veterinary Biologicals prior to release. For the potency test of CCV vaccine, it is necessary to use CCV antibody free dogs. The test requires not only kennels but high cost. To develop easy, efficient and economic potency test method for killed CCV vaccine using laboratory animals, a series of experiments with rabbits and guinea pigs were carried out in this study. In the preliminary test, the guinea pigs showed better immune responses than rabbits. The guinea pig was also easy to manage. So guinea pig was selected for the potency test animals. When the guinea pigs were inoculated twice with one dose of vaccine intramuscuarly each, slower and a little lower SN antibody titers were induced in guinea pigs than in dogs (about 2 kg body weight Beagle strain) given the same posology as guinea pigs'. It was concluded that guinea pigs could be substituted for dogs in the potency test of killed CCV vaccine.

• Korean Journal of Veterinary Service
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• v.13 no.1
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• pp.54-63
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• 1990

We have studied about the safety, immunity and protective potency in swine and experimental am mais of two inactivated vaccine produced with NYJ-1-87 strain of ADV that was isolated in Korea. Result obtained through the experiments were summarized as follows. 1. The safe potency of ADV antigens inactivated with BEI and formaline to mouse & guinea pig was on the whole good, but protective potency rates of those to challenge with ADV were 60-75％ without the differences to two antigens. 2. Safety, immunity & protective potency of ADV antigens inactivated with BEI and formaline to swine were on the whole excellent, except for a mild increase of rectal temperature in some pigs after challenge with ADV. 3. When virus excretion of the experimental groups after challenge with ADV was examed by swabbing of nasal, all pigs of control gorup excreted virus from 2 days p.c., partially to 10 days p.c.. But in vaccinated groups, only 25-50% of all pigs of each group excreted virus during experimental periods. 4. Titers of antibodies in swine & quinea pig vaccinated with inactivated ADV antigens become increased after the 1 weeth p.i. showing the highest liters on the 4-5 weeths p.i.

• Biomolecules & Therapeutics
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• v.10 no.2
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• pp.124-128
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• 2002

Hantaan (HTN) and Puumala (PUU) viruses are major etiological agents of hemorrhagic fever with renal syndrome (HFRS), an important public health problem in Korea after the Korean War. The objective of present study was to determine allergenic potency of an inactivated combination vaccine against HTN and PUU viruses inflection. As a series of allergenicity assessment, a homologous active systemic anaphylaxis (ASA) and homologous/heterologous passive cutaneous anaphylaxis (PCA) tests using the mice and guinea pigs were carried out. In the ASA test, no anaphylactic symptoms were observed in the guinea pigs sensitized with the vaccine alone as well as the vaccine emulsified with an adjuvant. By homologous PCA test, the vatscine did not induced the potential IgE antibody production in the sera obtained from the sensitized guinea pigs. In addition, IgE against the vaccine was not significantly enhanced from the mice inoculated with the vaccine, which was judged by the heterologous PCA test in rats. On the other hand, the inoculation of ovalbumin appeared to allergenic reactions both in the ASA and PCA tests. The results suggest that a combination vaccine against HW and PUU viruses have no allergenic potential in mice or guinea pigs.

• Journal of Microbiology and Biotechnology
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• v.12 no.5
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• pp.787-792
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• 2002

When developing a combined DTaP-HepB vaccine, toxicity and HBsAg immunogenicity are both important considerations. Thus, for a combined DTaP-HepB vaccine with a low toxicity, the effect of the DTaP content and $Al(OH)_3$, gel concentration on the vaccine toxicity was investigated. Within the range studied, the higher the concentrations, the higher the vaccine toxicity. The importance of the tetanus toxoid content in the combined DTaP-HepB vaccine was also revealed. A higher concentration of the tetanus toxoid was found to have a negative effect on the stability of the HBsAg immunogenicity in the combined vaccine. Accordingly, considering the factors affecting toxicity and HBsAg immunogenicity, a novel DTaP-HepB vaccine (30 Lf/ml of diphtheria toxoid, 5 Lf/ml of tetanus toxoid, 10 $\mu\textrm{g}$ PN/ml of acellular pertussis, 24 $\mu\textrm{g}$/ml of HBsAg, and 500 $\mu\textrm{g}$ Al/ml of $Al(OH)_3$ gel) was developed. It has a low toxicity and a stable HBsAg immunogenicity and also satisfies the potency criteria of K-FDA for a combined DTaP vaccine.

• Osong Public Health and Research Perspectives
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• v.8 no.6
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• pp.389-396
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• 2017

Objectives: To circumvent the limitations of the current golden standard method, colony-forming unit (CFU) assay, for viability of Bacille Calmette-$Gu{\acute{e}}rin$ (BCG) vaccines, we developed a new method to rapidly and accurately determine the potency of BCG vaccines. Methods: Based on flow cytometry (FACS) and fluorescein diacetate (FDA) as the most appropriate fluorescent staining reagent, 17 lots of BCG vaccines for percutaneous administration and 5 lots of BCG vaccines for intradermal administration were analyzed in this study. The percentage of viable cells measured by flow cytometry along with the total number of organisms in BCG vaccines, as determined on a cell counter, was used to quantify the number of viable cells. Results: Pearson correlation coefficients of FACS and CFU assays for percutaneous and intradermal BCG vaccines were 0.6962 and 0.7428, respectively, indicating a high correlation. The coefficient of variation value of the FACS assay was less than 7%, which was 11 times lower than that of the CFU assay. Conclusion: This study contributes to the evaluation of new potency test method for FACS-based determination of viable cells in BCG vaccines. Accordingly, quality control of BCG vaccines can be significantly improved.

• Journal of Microbiology and Biotechnology
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• v.13 no.3
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• pp.338-343
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• 2003

Various factors, such as the adsorption pH, adjuvant dose, and adjuvant age, which affect the adsorption degree and immunogenicity of an antigen, were investigated. In addition, the effect of pH, antigen content, and adjuvant content on immunogenicity was also studied through animal experiments. Within the ranges studied, a low pH for adsorption, freshly preformed gel, and low pH formulation for the combined DTwP-HepB vaccine were preferrable for the adsorption of the antigens. In addition, a higher DT content was found to have a positive effect on the HBsAg immunogenicity in the combined vaccine. Accordingly, considering the factors affecting the adsorption rate and immunogenicity of the antigens, a novel DTwP-HepB vaccine (40 Lf/ml of diphtheria toxoid, 15 Lf/ml of tetanus toxoid, 20 OU/ml of detoxified whole cell pertussis, $24\;\mu\textrm{g}$ of HBsAg, $24\;\mu\textrm{g}\;Al/ml\;of \;Al(OH)_3\;gel,\;776\;\mu\textrm{g}\; Al/ml\;of\;AIPO_4\;gel$, and pH 7.1) was developed, whose immunogenicity was comparable to the case of administrating, separately and simultaneously, a combined DTwP vaccine (40 Lf/ml of diphtheria toxoid, 15 Lf/ml of tetanus toxoid, 20 OU/ml of detoxified whole cell pertussis, $300\;\mu\textrm{g}\;Al/ml\;of\; AIPO_4\;gel$, and pH 7.1) and mono HepB vaccine [$Hepavax^{\circledR},\;24\;\mu\textrm{g}/ml$ of HBsAg and $500\;\mu\textrm{g}\;Al/ml\;of\;Al(OH)_3\;gel$], which satisfies the potency criteria of the K-FDA for a combined DTwP vaccine and mono HepB vaccine.