• Proceedings of the Korean Society of Veterinary Pathology Conference
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• 2003.10a
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• pp.58-58
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• 2003

The present experiment was carried out to study the pathogenesis of Newcastle disease by immunohisthochemistry and RT-PCR Two weeks aged specific pathogen-free chickens (White Leghorn) were inoculated with Newcastle disease virus(Kyojeongwon Strain : NDV) intranasally. (omitted)

• Korean Journal of Veterinary Research
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• v.38 no.3
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• pp.565-573
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• 1998

To study the specific tools for the diagnosis of Newcastle disease virus (NDV) in chicken, polymerase chain reaction (PCR) and its presumable conditions were evaluated for the detection of hemagglutinin-neuraminidase (HN) gene of NDV RNA. For these purposes, Kyojeongwon strain of the NDV was propagated in allantoic cavity of SPF embryonating chicken eggs, and viral RNA was extracted from fractionated virus after the allantoic fluids were ultracentrifuged with sucrose gradient. The first-strand cDNA was then made for the HN gene of NDV RNA by reverse transcription at $42^{\circ}C$ for 1 hour using specific primer complementary to the HN gene. The single-stranded cDNA was used as template in the PCR of the HN-DNA, and various conditions of the PCR were evaluated to set up method for the specific detection of the HN-DNA. The PCR conditions promising for the detection of HN gene consist of preheating at $94^{\circ}C$, 5 min, 30 cycles of denaturation at $94^{\circ}C$, 1 min, annealing at $55^{\circ}C$, 1 min and polymerization at $72^{\circ}C$, 2 min, and a cycle of extension at $72^{\circ}C$, 5 min. when NDVs of allantoic fluids without fractionation were applied to the above PCR condition, the HN genes were detected effectively not only from Kyojeongwon but from other velogenic strains such as Herts and a field isolate.

• Korean Journal of Poultry Science
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• v.27 no.2
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• pp.109-114
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• 2000

The objective of these experiments was to develop an attenuated thermostable Newcastle disease virus(NDV), CBP-1 strain isolated from infected pheasants. Safety, pathogenicity and protective effects against velogenic NDV were also investigated to evaluate if the attenuated NDV, CBP-1 strain could be a candidate for a new NDV vaccine strain. CBP-1 strain was passaged up to the 173 times by nine days old embryonated eggs and chicken embryo fibroblast(CEF) cell cultures. Its sensitivitly to lipid solvents and low pH, thermostability, mean death time(MDT), intracerebral pathogenicity index(ICPI) of one day old chicks and intravenous pathogenicity index(IVPI) of four weeks old chicks were examined. Safety, boosting and protective effects were tested by chicks mortality. CBP-1 NDV strain had significant thermostability at 56$\^{C}$ for 30 minutes. by hemagglutinin activity and egg infectivity test, but was not resistant to lipid solvent. It showed possibility to use as a feed or water vaccine because of the resistance to low pH. MDT, ICPI and IVPI of CBP-1 were attenuated from 51.5, 1.96, 2.60 to 112.4, 1.12, 1.45. These results implied that the 173rd passages in embryonated egg and CEF cell cultures induced a substantial attenuation of the pathogenicity of the parent virus, changing the virulence from velogenic to intermediate between mesogenic and lentogenic. After vaccination with CBP-1 at one day old by drinking water mortality was 17.5%. However, spray vaccination with B1 at one day old, CBP-1 at two weeks ild and challenge with velogenic Kyojeongwon strain at four weeks old showed 93.5% survival rate. Mortality of chicks, vaccination with 173rd passaged CBP-1 strain at one day old, two weeks old and challenge with Kyokeongwon strain at four weeks old, was 20.0%. The results of these studies indicated that partial attenuated CBP-1 strain tended to be a low safety for ND of broiler chicks and would need to be more successive attenuation.

• Korean Journal of Veterinary Service
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• v.27 no.1
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• pp.63-73
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• 2004

The present experiment was carried out to study the pathogenesis of Newcastle disease(ND), ND virus (NDV) antigens and genes in various organs from NDV inoculated chickens were detected by immunohistochemistry and RT-PCR. Immunohistochemically, NDV antigens were detected in the spleen, thymus, cecal tonsil, proventriculus, trachea and lungs at 12 hour post-inoculation (hpi). Viral antigens were localized mainly in the cytoplasm of lymphocytes and macrophages. After 48 hpi, clinical findings of the affected chickens were open-mouth breathing, conjunctivitis, watery diarrhea and edema around the eye and neck. After 72 hpi, chickens showed muscular tremor, paralysis of the legs and wings, and coma. Histopathological results consist of multi-focal necrosis with hemorrhages in lymphoid aggregates of the intestinal tracts, necrosis of the lymphoid tissues, neuronal degeneration and necrosis, and perivascular cuffing. Using RT-PCR, virus genes were detected in the spleen and proventriculus at 48 hpi, and in the brain at 60 hpi.

• Korean Journal of Veterinary Research
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• v.46 no.3
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• pp.215-224
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• 2006

In order to search the availability of the lectin extracted from Korean mistletoe(Viscum album coloratum) as an adjuvant for the avian vaccines, attempts were made to determine toxicity of the lectin in chicks and its immunostimulating activity on the inactivated vaccines against Newcastle disease virus(NDV). For the determination of toxicity, the lectin was injected into the thigh muscle of SPF chicks(Charles River) of 1-week-old and observed hematologically and pathologically. For the determination of immunostimulating effects, lectin-adjuvanted, inactivated NDV vaccines were injected into the thigh muscle of SPF chicks in the same age group. Sera of the chicks were examined for the hemagglutination-inhibition(HI) antibodies induced, their HI titers and reaction to the NDV antigens. The data were further compared with those from aluminum hydroxide [$Al(OH)_3$]-adjuvanted vaccines and vaccines without adjuvant, and the results are as follows. There were no significant changes observed in the values of RBC, WBC, Hb, PCV, MCV, MCH, MCHC, AST, ALT, BUN, creatinine and total proteins in the chicks administered with lectin of 1.1, 2.2 and $22.2{\mu}g/kg$ body weight, which means the lectin has no effects on blood values and functions of liver and kidney. In histopathologic observation, no lesions were observed in the brain, heart, liver, lung, spleen, kidney, thymus and bursa of Fabricius of the chicks administered with lectin of 1.1, 2.2 and $22.2{\mu}g/kg$ body weight. There were inflammatory lesions, such as congestion, hemorrhage, edema, infiltration of macrophages and coagulation necrosis observed in the thigh muscle of chicks administered with lectin of $22.2{\mu}g/kg$ body weight, whereas no changes were observed in 1.1 and $22.2{\mu}g/kg$ lectin administered chicks. In chicks immunized with lectin($4.4{\mu}g/kg$ of body weight)-adjuvanted B1, LaSota and Ulster 2C vaccines, HI titers in reciprocal values for $log_2$ were 1.8-2.2 at 1 week after vaccination, which was similar with those of 1.5-2.9 by $Al(OH)_3$-adjuvanted vaccines. The HI titers by the lectin-adjuvanted vaccines reached to 3.9-5.3 at 4 weeks, whereas those by the $Al(OH)_3$-adjuvanted vaccines were more high as 7.3-9.3. Meanwhile, the immunostimulating effects of the lectin were recognized while compared to the HI titers with 2.4-3.7 in chicks immunized with vaccines without adjuvants at 4 weeks after vaccination. The chicks immunized with lectin-adjuvanted vaccines were enough to resist challenges by Kyojeongwon strain, a very virulent NDV at 4 weeks after vaccination as well as chicks immunized with $Al(OH)_3$-adjuvanted vaccines. The HI titers by the lectin-adjuvanted vaccines reached to high level as 8.7-10.3 as those with 8.2-9.6 by the $Al(OH)_3$-adjuvanted vaccines at 6 weeks after vaccination, which may be the booster effects by the challenge virus. Antibodies specific to the HN and F antigens of NDV were observed in the sera of both chicks immunized with lectin-adjuvanted vaccines and $Al(OH)_3$-adjuvanted vaccines.