• 한국생물공학회:학술대회논문집
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• 2005.04a
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• pp.203-206
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• 2005

TGE (Transmissible Gastroenteritis) caused by a virus belonging to family coronavirus, results in an acute infection of the small intestine of the pig. The optimum operation variables such as multiplicity of infection (MOI), infection time and harvest time were investigated for TGE vaccine production by immobilized ST(swine testicle) cells. In the culture supplemented with 5% serum, maximum virus titer of $1.2{\times}10^6pfu/ml$ was obtained at the conditions of 0.01 MOI, 2day infection time, and 1 day harvest time. Serum is a potential source of bacterial, mycoplasmal and viral contamination, and it has a possibility of the introduction of serum proteins, prion and pyrogens into the final product. For these reasons, much attention has been focused on the development of serum-free media. A new serum-free media (SFM) has been developed in order to produce TGE vaccine of high quality with low cost. The performance of SFM developed was compared with other commercially available serum-free media and serum supplemented media in terms of virus productivity. The cultures with serum-free media showed higher titer than that with serum supplemented media. Among various serum-free media tested, CHO-S-SFMII showed highest virus titer.

• Journal of Veterinary Clinics
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• v.17 no.1
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• pp.45-51
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• 2000

Sera from 425 Korean native and 203 Holstein cattle were collected from October 1994 to September 1995 from dairy farms and slaughterhouses in Chonnam province to study the exposure rate to bovine respiratory syncytial virus(BRSV). Serum antibody titers against BRSV were measured by neutralization test, and results were as follows: Overall prevalence of seropositive cattle to BRSV were 74.5%, and the exposure rate to BRSV was higher among the Holstein (77.3%) than among the Korean native cattle(73.2%). The serum antibody titers against BRSV ranged from 1:2~$\geq$1:256 in both species. Among Korean native cattle, the most frequent serum antibody titer was 1:4 against BRSV(19.3%), while only 1.4% of seropositive cattle had serum titer of $\geq$1: 256. Among Holstein cattle, 22.7% of examined cattle contained serum titer of 1:8, while 1.5% of seropositive cattle showed $\geq$ 1:256. Antibody titers against BRSV were higher among males than females in both Holstein (82.1% vs. 73.1%) and Korean native (74.5% vs. 69.2%) cattle. Prevalence of seropositive cattle by age in both species were evenly distributed, although the highest number (76.9%) of seropositive were at the age of 3 in Korean native cattle, while 83.5% of seropositive Holstein cattle were of 2 years old. The lowest seropositive rate was observed in cattle of less than 1 year old(25.0%). Seasonal occurrunce of BRSV was the highest in spring season in both Holstein (86.6%) and Korean native (81.0%) cattle (P<0.05).

• Korean Journal of Veterinary Research
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• v.42 no.3
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• pp.371-376
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• 2002

Swine respiratory diseases have induced severe economic lasses in swine industry worldwide. Therefore, several methods have been made and applied to prevent and control the diseases. However, these methods still have a problem and also induce side effects. Recently, the use of egg yolk antibody was introduced to control and prevent the diseases as one of new trials. As a study of using egg yolk antibody, antibody titers against several different antigens of major pathogens in swine respiratory diseases were compared in egg yolk and serum of hens immunized with those antigens. The titers were measured by ELISA using the antigens as coating antigens. The relationship in antibody titers between egg yolk and serum were identified by analysis of variance for linear regression. Almost of antigens used in this study showed the high relationship in antibody titers between egg yolk and serum (r = 0.87 ~ 0.93) even though the relationship in antibody titers against P. multocida A:3 IROMP was slightly low (r = 0.74)(P<0.01). These results indicated that antibody titer in egg yolk could be useful to predict the titer in serum of chicken.

• Korean Journal of Veterinary Service
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• v.31 no.3
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• pp.315-329
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• 2008

A total of 710 bovine serum samples which are composed 532 bovine serum samples showed negative reaction and 178 bovine serum samples showed positive reaction with tube agglutination test (TAT) from North area of Gyeong-nam, Korea were tested using all the 3 assays which are Rose-Bengal test(RBT), tube agglutination test (TAT) and enzyme-linked immunosorbent assay (ELISA, two types) and analyzed for evaluation of specificity, sensitivity, reproducibility and predictive value. In the comparison of serum antibody titer agglutination test, RBT showed almost agreement with TAT. In the comparison of TAT and two types of ELISA method, they showed difference in specificity and sensitivity about 5%. But there is no significant difference in detecting sensitivity between two types of ELISA method and TAT. In serologic tests for bovine brucellosis, the new assay ELISA would be a good candidate for serologic survey for bovine brucellosis in Korea because it is efficient in detecting many test samples quickly. But the serum agglutination tests (RBT, TAT) are more economical and easy assay for detection. In the test of comparison of antibody titer between first day of finding and 10 days after finding by TAT, there was no change in 55% (76/139) of positive cattle.

• YAKHAK HOEJI
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• v.34 no.5
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• pp.348-364
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• 1990

The activities of twenty-one flavonoids and their related compounds on the hypersensitivity reaction against various antigens were studied in vitro and in vivo. 1. Generally flavonoids inhibited significantly the homologous passive cutaneous anaphylaxis (PCA) induced by reaginic antibody as compared as anaphylaxis by compound 48/80-induced mast cell degranulation, and so more strongly active in the IgE-mediated anaphylaxis than non-IgE-mediated anaphylaxis. 2. Flavonids inhibited remarkably Arths reaction, hemolysin titer, delayed hypersensitivity, haemagglutinin titer, rosette forming cells and plague forming cells against sheep red blood cells, and so it exhibited that flavonoids inhibited type 2, 3 and 4 hypersensitivity. 3. Quercetin, kaempferol, hesperetin, disodium cromoglycate, malvin and baicalein were active dose-dependently in the all types of hypersensitivity. Fisetin, daidzein, morin, narigin, flavone, catechin, rutin, hesperidin, neophsperidin, apigenin and chrysin were significantly active in the various types of hypersensitivity, but apigenin, rutin and catechin were less active in the delayed hypersensitivity. Taxifolin was significantly active in PCA and histamine-induced anaphylaxis except other types of hypersensitivity. Rotenone and cyanin also inhibited all types of hypersensitivity, but they are toxic. 4. Based on these results from hypersensitivity, the following flavonoid structure-activity relationships became apparent. 1) Flavonoids with $C_{2-3}$ double bond in C-ring were more active than that of $C_{2-3}$ saturation. 2) Flavonoids with $C_4$ ketone group in C-ring were more active than abscence of them except catechin and malvin. 3) Flavonoids with benzene ring at positions 2 or 3 in C-ring exhibited same activities. 4) Flavonoids with opening of the C-ring does not abolish their activities. 5) The glycosylated flavonoids in position 3 or 7 was less active than their aglycone. 6) Flavonoids with the more hydroxy group in A and B-ring were more active. 7) Flavonoids with or without $C_3-OH$ did not change their activities.

• The Journal of Korean Society of Virology
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• v.26 no.1
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• pp.67-76
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• 1996

The methods that make Hantavirus grow consist of inoculation into the experimental animals and cultured cells. The cultured cells, such as Vero-E6 and A549 cells, have been usually used for isolation of the virus and the animals, such as mice and rats, are used for large scale preparation of the virus so far. Furthermore, the cell can be used to maintain the virus and assay the infectivity and the animals can be used for the experiment of viral pathogenicity and challenge for assessment of vaccine. Apodemus mice, the own natural host of the virus, has been used for challenge test of Hantaan virus. However it has been pointed out to difficult handling and breeding the animal in laboratory. Therefore, we attempted to establish a new animal model for challenge test at the time of isolation of Maaji virus which is a new hantavirus similar but distinct to Hantaan virus. In suckling hamster, the titer of Maaji virus and the lethality to mice of the virus were increased gradually in the titer and lethality through passage by intracerebral (IC) inoculation. We tried to re-adapt this brain virus to lung of weanling hamster. The brain passaged virus was inoculated into weanling hamster intramuscularly. Again, the titer of the virus in lung was also increased by continuous passage of this virus. This facts could regarded as adaptation to new environment in which the virus proliferates. To identity the virus passaged in hamster with Maaji virus, both of the virus passaged in hamster brain and lung were compared with Maaji virus (MAA-I) and Hantaan virus (HTN 76-118) by means of restriction fragment length polymorphism (RFLP) and slingle strand conformation polymophism (SSCP). As a result, we conclude that Maaji virus could be adapted successfully to weanling hamster through this passage strategy. Utilizing this adapted Maaji virus strain, hamster model is able to be used for challenge test in hantaviral vaccinology and further experiments utilizing hamster system as a rather available and convenient lab animal are expected.

• Korean Journal of Veterinary Research
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• v.31 no.4
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• pp.479-484
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• 1991

Encephalomyocarditis(EMC) virus was isolated from the mummified and stillborn pigs at a swine farm in Chonnam Province, experienced with EMC infection over the period Oct.~Dec. of 1989. In addition some cultural, serological properties of the isolates and experimental infections in the piglets were studied. The results obtained were as follows; 1. Two EMC virus strains with HA titers and CPE similar to EMC-ATCC were established in a baby hamster kidney (BHK)-21 cell line by inoculating homogenates of brain and heart of the 19 mummified or stillborn pigs and designated $K_3$ and $K_{11}$. 2. At the second BHK-21 cell line passage of the initial isolates CPE appeared after incubation for 16~18 hours, while at the fourth and fifth passage the highest titer of HA was recorded, titer of HA using rat and guinea pig erythrocytes. 3. One pig inoculated with the isolate $K_3$ showed dyspnea as clinical signs and died at the 10 days after inoculation at necropsy white necrotic foci were observed from the dead animal heart. 4. Although all the rest surviving pigs showed increases in antibody titer and body temperature of $40^{\circ}C$ above for the initial 2~4 days followed by the return to normal, there were no gross lesions when the animals were sacrificed at the 2 weeks after inoculation.

• Asian-Australasian Journal of Animal Sciences
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• v.14 no.2
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• pp.163-169
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• 2001

Despite the high potency of the retrovirus vector system in gene transfer, one of the main drawbacks of has been difficulty in preparing highly concentrated virus stock. Numerous efforts to boost the virus titer have ended in unsatisfactory results mainly due to fragile property of retrovirus envelope protein. In this study, to overcome this problem, we constructed our own retrovirus vector system producing vector viruses encapsulated with VSV-G (vesicular stomatitis virus G glycoprotein). Concentration process of the virus stock by ultracentrifuge did not sacrifice the virus infectivity, resulting in more than 108 to 109 CFU (colony forming unit) per ml on most of the target cell lines tested. Application of this high-titer retrovirus vector system was tested on chicken embryos. Injection of virus stock beneath the blastoderms of pre-incubated fertilized eggs resulted in chick embryos expressing E. coli LacZ gene with 100% efficiency. Therefore, our results suggest that it is possible to transfer the foreign gene into chicken embryo using our high-titer retrovirus vector.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.6
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• pp.884-891
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• 2006

The effect of dietary vitamin E supplementation on immune responses was studied in breeder chickens during the maturing period. In experiment 1, 17-week old female birds were fed corn-soybean meal based diets supplemented with either 0, 40, 80, 120, or 160 mg vitamin E (all-rac-${\alpha}$-tocopherol acetate)/kg diet for 19 weeks. In experiment 2, 23-week old male birds were fed the corn-soybean meal based diet supplemented with either 0, 20, 40, 80 or 160 mg vitamin E/kg diet for 8 weeks. The chickens were evaluated for growth performance, antibody titer to sheep red blood cell (SRBC), Newcastle disease virus (NDV), infectious bursal disease virus (IBDV) and infectious bronchitis virus (IBV), and skin response to phytohemagglutinin-P (PHA-P). The results showed that supplemental vitamin E improved body weigh gain of laying pullets during peak-laying period but had no significant effect on growth performance of cockerels. For cockerels, addition of 20 mg vitamin E/kg diet significantly enhanced (p<0.05) immune response to SRBC compared to those added with 0, 80 and 160 mg vitamin E/kg diet; addition of 20 mg vitamin E/kg diet had higher (p<0.01) antibody titer to IBDV than those added with 40-160 mg vitamin E/kg diet. No significant effects on immune response were observed in laying pullets fed supplemental vitamin E. The findings suggest that moderate supplementation of vitamin E may enhance immune responses to selective antigens in cockerels but excessive vitamin E may depress specific immune response.

• Korean Journal of Veterinary Service
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• v.13 no.1
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• pp.96-102
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• 1990

The immune responses of commercial layer chickens against Newcastle disease(ND) were compared among different administration methods and times of vaccination during 4 weeks of age. A total of 372 day-old chickens were divided into 4 groups of 93 birds each. Each of 3 groups was received a commercially available B$_1$live vaccine via drinking water, eye instillation or spray method at one, 14 and 28 days of age. One group was used as an unvaccinated control. At two and 4 weeks after each time of vaccination, 15 birds from each group were collected randomly out and challenged with virulent ND virus at the dose of $10^5E1D_{50}$ per bird. Ten to 15 birds from each group were bled at two weeks intervals from day old to 8 weeks of age for hemagglutination inhibition antibody titer, The protection rate was generally low regardless of the times of vaccination although two or more times vaccination gave higher protection than once vaccination. The low protection was considered due to low titer of the vaccine used since the vaccine titer was less than $10^{3.5}EID_{50}$ per bird. Spray method gave better protection compared to eye instillation or drinking water method which resulted in lowest response. Majority of birds showed clinical signs of ND between 3 and 6 days after challenge. Death occured one or two days after onset of symptoms. Major clinical signs observed were depression(94%), anorexia(84%), diarrhoea(29%), difficult breath(15%) and torticollis(10%). Hemorrhagic lesions on post mortem were seen in duodenum(51%), trachea(35%), illeum(13%), ceacal tonsil(11%), proventriculus(10%) and some other odrgans.