• The Journal of Korean Society of Virology
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• v.28 no.3
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• pp.233-245
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• 1998

The gene encoding F protein of CBP-1 strain, a heat-stable Newcastle disease virus (NDV) isolated from the diseased pheasants in Korea, was characterized by reverse transcription-polymerase chain reaction (RT-PCR), nucleotide and amino acid sequences. Virus RNA was prepared from the chorioallatoic fluid infected with NDV CBP-1 virus and cDNA was amplified by RT-PCR, cloned and sequenced to analyze. The PCR was sensitive as to detect the virus titer above $2^5$ hemagglutination unit. 1.7kb (1,707bp) size of the cDNA was amplified and cloned into BamHI site of pVL1393 Baculo transfer vector. The nucleotide sequences for F protein were determined by dye terminator cyclic sequencing using four pairs of primers, and 553 amino acid sequences were predicted. In comparison of the nucleotide sequence of F gene of CBP-1 with those of other NDV strains, the homology revealed 88.8%, 98.5% and 98.7% with Kyojungwon (KJW), Texas GB and Beaudette C strains, respectively. As the deduced 553 amino acid sequences of F protein of CBP-1 were compared with those of other NDV strains, the homology appeared 89.9%, 98.7% and 98.9% with KJW, Texas GB and Beaudette C strains, respectively. The putative protease cleavage site (112-116) was R-R-Q-K-R, indicating that CBP-1 strain is velogenic type. The amino acid sequences include 6 sites of N-asparagine-linked glycosylation and 13 cysteine residues. These data indicate that the genotype of CBP-1 strain is more closely associated with the strains of Texas GB and Beaudette C than KJW strain.

• 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 Poultry Science
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• v.39 no.2
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• pp.113-120
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• 2012

Newcastle disease virus (NDV) Kr005/V strain was generated through 55 serial passages of NDV Kr005 strain in Vero cells. The Kr005/V virus yielded high infective titers of $10^{7.8}$ $TCID_{50}/mL$ in Vero cells and the infected cells showed cytopathic effects such as marked cell rounding, though less frequent syncytia. The Kr005/V virus was heat-stable and classified into the lentogenic type with a Mean Death Time (MDT) of 120h or greater while the Kr005 strain was heat-labile and velogenic (MDT of 49.6 h). Only the single amino acid substitution (T to S) was observed at position 433 of the HN protein of the Kr005/V strain, whereas no amino acid change was found in the F protein. The Kr005/V input virus correlated well (correlation coefficient $r^2$=0.97) with the Kr005 virus when ten field sera were tested by virus neutralization test. The biological properties and usefulness of Vero cell-adapted Kr005/V virus were discussed.

• Korean Journal of Veterinary Service
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• v.42 no.4
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• pp.245-250
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• 2019

Newcastle disease (ND) is an infectious poultry disease that caused high mortality and reduced egg production. NDVs are regularly present in the domestic duck population. And ducks play a possible role in the maintenance and transmission of NDVs. While we were monitoring the Avian Influenza, NDVs were isolated from field samples by accident. So we analysed the biological and genetic characteristics of these viruses. Lentogenic NDVs were isolated from two farms among twenty breeder duck farms. The ages of ducks were 39 weeks old in the 'A' farm and 3~72 weeks old in the 'B' farm. And they were not inoculated with the NDVs vaccine. In the biological characteristics, the both viruses which separated from the farm 'A' and 'B' were thermostable. The amino acid sequence of a site from 112 to 119 in the fusion (F) protein was 'GKQGRLIG' which has monobasic motif in the samples of both farms. And this means the separated NDVs are lentogenic. Phylogenetic analysis was performed by entire nucleotide sequence of F protein. The virus strains from the A farm (MN095239) and the B farm (MN095240) belonged to class II genotype I. Using the analysis of whole F protein nucleic acid sequence, the MN095239 (GenBank) had homology with Ulster strain about 99.95% and the MN095239 (GenBank) had homology with KR/CK/KU_LBM255/09 strain about 99.89%. NDV surveillance is needed to investigate epidemiological relationship of domestic breeder duck isolates in Korea.

• Korean Journal of Poultry Science
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• v.28 no.2
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• pp.83-89
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• 2001

Newcastle disease virus, CBP-1 strain isolated from Korean pheasants was passaged for 173 times by 9-day-old specific pathogenic free (SPF) embryonated eggs at $37^{\circ}C$ (parent strain) and subsequently passaged for 15 (cold attenuation (CA) -15) and 30(cold attenuation (CA) -30) times by 10-day-old of commercial broiler chicks embryonated eggs at $29^{\circ}C$, respectively, The Physical and chemical properties (sensitivity to lipid solvents, low pH and thermostability), pathogenicity (mean death time, intracerebral pathogenic index and intravenous patho-genic index), safety, booster or protective effect and characterization of temperature sensitivity were measured in cold attenuated CA-15 or 30 strain and compared to those of parent CBP-1 strain. NDV, CBP-1 CA-30 strain acquired cold attenuation and decreased infectivity at $41^{\circ}C$ compared to those of parent strain grown at $37^{\circ}C$. It lost hemagglutination activity (HA) and cell infectivity at $56^{\circ}C$ for 30, 60, and 120 Min. CA-30 strain treated with ethyl ether also lost its HA and cell infectivity. Both CA-30 and parent strains exhibited a little resistant to HA at pH 3.0 glycine HCI buffer. Intracerebral pathogenic index (ICPI) and intravenous pathogenic index (IVPI) of parent strain were 1.12 and 1.45, but decreased to 0.75 and 0.00 in CA-30 strain, respectively. The safety was evaluated by mortality in chicks inoculated with 10$^{4.0}$ EID$_{50}$ /0.1 ml. The mortalities of parent, CA-30 and commercial Bl strains were 17.5, 12.0 and 0.0%, respectively. The safety of CA-30 strain was higher than that of parent strain. The booster effects of CA-30 strain and parent strain performed in 4-week-old chicks after being vaccinated with primary commercial Bl strain.