• 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.

• Journal of Sericultural and Entomological Science
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• v.25 no.2
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• pp.37-43
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• 1984

The prevalence of the infectious flacherie virus (FV) disease causes a severe damage to cocoon yield and various methods to control the disease have been studied. In this regard, guanidine hydrochloride (GH), one of the guanidine derivatives known as the most inhibitory agent against the replication of picorna virus, was applied to silkworms per os with mulberry leaves and the results were as follows. 1. The application of GH below 0.01% of the chemical concentration did not give any damage to silkworm larvae. 2. The transmission of the virus disease by introducing the FV infected larvae to the healthy larvae group was proportioned to the number of infected larvae. When l% of infected larvae was introduced to the rearing tray of healthy larvae, the pupation rate was 70.7%(79) and it was 38.4% (43) to 5% of infected larvae introduced, while the control of non-mixed with infected larvae gave 89.2% (100) of pupation rate. The cocoon yield from 10,000 larvae also showed the same tendency as the pupation rate. 3. The inhibitory effect of GH against the replication of FV showed ten times in treatment of 0,01% of the chemical agent compared to the non-treatment. 4. The successive application of GH after virus inoculation to silkworm larvae led to the most effective on the inhibition of the virus replication. 5. The immediate application of GH after the virus inoculation also gave the best effect on the inhibition of the virus replication in silkworm larvae. 6. The effect of GH on the inactivation of FV in vitro was not observed.

• Korean Journal of Poultry Science
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• v.32 no.2
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• pp.113-123
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• 2005

Avian influenza (AI) virus (AIV) is distributed worldwide and it has been isolated from various species of wild and domestic birds. AI transfers with high speed and shows diverse pathogenicity syndroms. In Korea, several low Pathogenic AIV, H9N2, have been isolated from the commercial farms with severe decrease of egg production and mortality resulted in severe economic loss since 1996. Therefore, it has been requested to develop AI vaccines to prevent clinical signs and economic losses from the field infection of AIV. To develop a killed vaccine that efficiently prevents low pathogenic AIV (H9N2), evaluation on the pathogenicity and selection of an inactivator for H9N2 is taking place and is being tested safety and immunogenicity of vaccine produced. Based on the pathogenicity test and viral reisolation test, the ADL0401 isolate is the characteristic low pathogenic AIVs and has fairly similar biologic functions compared with MS96 which is the official low pathogenic AIV (H9N2) and one of the predominant AIV isolated from poultry farms in Korea. In antigenicity tests, the ADL0401 and MS96 virus have no significant antigenic difference. In inactivation tests, the ADL0401 isolates can be easily inactivated with $0.1\%$ Formalin at $37^{\circ}C$ within 1 hour with a little decrease of HA titer. The vaccine developed in the present report has no harmful effect on bird and forms good immune capability. Therefore, the isolates, ADL0401 can be used for a killed vaccine which can reduce the clinical signs and viral shedding in the birds infected with H9N2 low pathogenic AIVs.

• Korean Journal of Microbiology
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• v.41 no.3
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• pp.216-224
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• 2005

Chromatography has now been used successfully to provide the requisite purity for human plasma-derived biop-harmaceuticals such as coagulation factors and immunoglobulins. Recently, increasing attention has been focused on establishing efficient cleaning procedures to prevent potential contamination by microorganisms as well as carry-over contamination from batch to batch. The purpose of present study was to develop a cleaning validation system for the assurance of virus removal and/or inactivation during chromatography process. In order to establish an assay system for the validation of virus clearance during chromatography cleaning process, a quantitative real-time PCR method for porcine parvovirus(PPV) was developed, since PPV, a model virus for human parvovirus B19, has a high resistance to a range of physico-chemical treatment. Specific primers for amplification of PPV DNA was selected, and PPV DNA was quantified by use of SYBR Green I. The sensitivity of the assay was calculated to be 1.5 $TCID_{50}/ml$. The established real-time PCR assay was successfully applied to the validation of PPV removal and cleaning during SP-Sepharose cation chromatography for thrombin purification and Q-Sepharose anion chromatography for factor VIII purification. The comparative results obtained by real-time PCR assay and infectivity titrations suggested that the real-time PCR assay could be a useful method for chromatography cleaning validation and that it could have an additive effect on the interpretation and evaluation of virus clearance during the virus removal process.

• Pediatric Infection and Vaccine
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• v.4 no.1
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• pp.116-125
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• 1997

Purpose : Studies on the duration of immune response against Japanese encephalitis virus from recipients with JE vaccine (Nakayama-NIH strain) in Korea. Methods : To determinate the immune response and the duration of antibody against JE vaccine, 213 students were examined since 1994 using hemmaglutination inhibition test and plaque reduction neutralization test (PRNT). Results : 24 months after the first vaccination, haemmaglutination inhibition and neutralizing antibody maintained from the recipients 63.4% (>1:20) and 100% (>1:20), respectively. In April 1996, one dose booster to the same recipients those who were vaccinated in 1994, the GMT antibody for HI and PRNT titer were both increased from 1:11.6 to 1:13.2 and 1:275.7 to 1:348.1, respectively, after 6 months booster (after 30 months from the initial vaccination). This results showed that the antibody from the active immunity could be maintained more than 12 months after the initial vaccination. On the basis of these results, inactivated killed JE vaccine (Nakayama-NIH strain) using for preventing against JE purpose seems to produce antibody enough to protect against JE at present. Conclusions : Along with the results of this study demonstrating duration of antibody, the active immunization could be maintained as long as by initial vaccination of 2 doses, a single dose of booster vaccination made during a period of 1 month to 12 months and the successive booster vaccination by 2 or 3 year intervals. However, the immunization schedule should be concerned with both epidemiology of disease and the immune response of vaccinated individuals.

• Pediatric Infection and Vaccine
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• v.7 no.1
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• pp.120-128
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• 2000

Purpose : Active immunization against hepatitis A with an inactivated vaccine reveals excellent immunogenicity, tolerability and protective efficacy. Inactivated hepatitis A vaccines have been selectively used since 1996 in Korea to prevent hepatitis A. This study was performed to assess the immunogenicity and reactogenicity after two doses of HM175 strain hepatitis A vaccine in healthy Korean children. Methods : 128 healthy children(M/F; 65/63) aged 1 to 15 years, who were seronegative for hepaitatis A, participated in this study. A alum-adsorbed vaccine containing 720 EL.U of antigen form HM175 hepatitis A strain per 0.5 mL dose was injected intramuscularly on the deltoid area. The second dose was given 6 months later, Anti-HAV antibodies were measured by ELISA before and 1 month after each vaccination to assess the immunogenicity. Any local and general adverse events were reported by patients parents with the prepared questionnaire after each vaccination. Results : 120 volunteers(M/F; 60/60) completed the whole series of the study. Seroconversion occurred in all cases after primary and booster vaccination. The mean anti-HAV antibody titer after primary vaccination was 389.2mIU/mL, and 3,609mIU/mL after booster vaccination. And levels of anti-HAV antibodies after booster immunization were significantly higher in female children. The most common local adverse event was soreness on the injection site, but it was mild and resolves within 3 days. Fever was not reported after booster vaccination. Conclusion : Based on these data, we conclude that the inactivated HM175 strain hepatitis A vaccine is highly immunogenic and tolerable in healthy Korean children.

• Pediatric Infection and Vaccine
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• v.17 no.2
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• pp.156-168
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• 2010

Purpose : To compare immunogenicity and reactogenicity of a combined diphtheria-tetanus-acellular pertussis-inactivated poliovirus vaccine (DTPa-IPV, $Infanrix^{TM}$ IPV, GlaxoSmithKline Biologicals) with co-administration of commercially available DTPa and IPV vaccines at separate injection sites (DTPa+IPV). Methods : A total of 458 infants aged 8-12 weeks were randomized to receive three-ose primary vaccination at 2, 4 and 6 months with DTPa-IPV or DTPa+IPV. Blood samples were collected pre and post vaccination for measurement of immune responses. Reactogenicity was assessed following each dose using diary cards. Results : One month post-dose 3, seroprotection rates for anti-diphtheria, anti-tetanus and anti-poliovirus types 1, 2 and 3 were ${\geq}99.5%$ and vaccine response rates to pertussis antigens were at least 98.6% in both DTPa-IPV and DTPa + IPV groups. Non-inferiority between the groups was demonstrated based on pre-defined statistical criteria. Incidences of both local and systemic symptoms were within the same range across both groups with grade 3 symptoms reported following no more than 4.3% of DTPa-IPV doses and 4.5% of DTPa + IPV doses. Two serious adverse events (both pyrexia) after DTPa-IPV administration were considered vaccine-related. Both infants recovered fully. Conclusion : Combined DTPa-IPV vaccine was immunogenic and well tolerated when used as a three-dose primary vaccination course in Korean infants. DTPa-IPV could be incorporated into the Korean vaccination schedule, reducing the number of injections required to complete primary immunization.