• Journal of Veterinary Science
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• v.22 no.4
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• pp.56.1-56.10
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• 2021

Background: Fluorescent antibody virus neutralization (FAVN) test is a standard assay for quantifying rabies virus-neutralizing antibody (VNA) in serum. However, a safer rabies virus (RABV) should be used in the FAVN assay. There is a need for a new method that is economical and time-saving by eliminating the immunostaining step. Objectives: We aimed to improve the traditional FAVN method by rescuing and characterizing a new recombinant RABV expressing green fluorescent protein (GFP). Methods: A new recombinant RABV expressing GFP designated as ERAGS-GFP was rescued using a reverse genetic system. Immuno-fluorescence assay, peroxidase-linked assay, electron microscopy and reverse transcription polymerase chain reaction were performed to confirm the recombinant ERAGS-GFP virus as a RABV expressing the GFP gene. The safety of ERAGS-GFP was evaluated in 4-week-old mice. The rabies VNA titers were measured and compared with conventional FAVN and FAVN-GFP tests using VERO cells. Results: The virus propagated in VERO cells was confirmed as RABV expressing GFP. The ERAGS-GFP showed the highest titer (10^8.0 TCID₅₀/mL) in VERO cells at 5 days post-inoculation, and GFP expression persisted until passage 30. The body weight of 4-week-old mice inoculated intracranially with ERAGS-GFP continued to increase and the survival rate was 100%. In 62 dog sera, the FAVN-GFP result was significantly correlated with that of conventional FAVN (r = 0.95). Conclusions: We constructed ERAGS-GFP, which could replace the challenge virus standard-11 strain used in FAVN test.

• Korean Journal of Veterinary Research
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• v.58 no.4
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• pp.211-217
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• 2018

Mesenchymal stem cells (MSCs) are useful candidates for tissue engineering and cell therapy. Physiological cell environment not only connects cells to each other, but also connects cells to the extracellular matrix that provide mechanical support, thus exposing the entire cell surface and activating signaling pathways. Hydrogel is a polymeric material that swells in water and maintains a distinct 3-dimensional (3D) network structure by cross linking. In this study, we investigated the optimized cellular function for canine adipose tissue-derived MSCs (cAD-MSCs) using hydrogel. We observed that the expression levels of Ki67 and proliferating cell nuclear antigen, which are involved in cell proliferation and stemness, were increased in transwell-hydrogel (3D-TN) compared to the transwell-normal (TN). Also, transforming growth factor-${\beta}1$ and SOX9, which are typical bone morphogenesis-inducing factors, were increased in 3D-TN compared to the TN. Collagen type II alpha 1, which is a chondrocyte-specific marker, was increased in 3D-TN compared to the TN. Osteocalcin, which is a osteocyte-specific marker, was increased in 3D-TN compared to the TN. Collectively, preconditioning cAD-MSCs via 3D culture systems can enhance inherent secretory properties that may improve the potency and efficacy of MSCs-based therapies for bone regeneration process.

• Journal of the korean veterinary medical association
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• v.23 no.9
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• pp.603-610
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• 1987

The pathological and microbiological studies were carried out to investigate an acute, febrile, highly fetal, infectious disease of rabbits that had occurred in the Winter and in the Spring and that had begun to be reported in Korea from November, 1985. The clinical signs of this disease were characterized by high fever, lethargy, piercing shriek, convulsion, and sudden death with epistaxis, but often they were not observed. The predominant pathogical findings were severe congestion and hamorrhage in trachea, dark brown discoloration of liver by diffuse necrosis or acute viral hepatitis, and hamorrhagic damages of lung, heart, spleen, kidney, etc. The etiological agent was a small round virus, in 25-35nm in diameter and without envelope, thus looking like a picorna virus. This disease resembled what was called the 'Viral Hamorrhagic Pneumonia in Rabbits'(tentative name) that had been reported for the first time in China in 1984. It will be desirable that the disease should be renamed as the 'Viral Hemorrhagic Fever in Rabbits', the 'Acute Viral Hepatitis in Rabbits', etc. because of its charateristics and the basis of pathological findings. An inactivated vaccine is now in the process of preparation for the prophylaxis of this viral disease.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.46 no.5
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• pp.582-588
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• 2013

The impact of global warming on aquatic systems has been a priority research area in the past decade. However, the possibility that increased temperatures will cause shifts in viral disease outbreaks has not been well addressed. In the present study, with increasing water temperature (WT) in the coastal area of Korea, we estimated the possibility of changes in fish viral diseases. From the present time, WT may rise between 0.62 and $1.7^{\circ}C$ by 2050, and the effect on aquaculture could be more adverse than benefitial. Red seabream iridovirus disease (RSIVD) and viral nervous necrosis (VNN) cause high mortality above 22 and $24^{\circ}C$, respectively, and outbreaks could commence earlier and persist for prolonged periods. Nevertheless, the period of occurrence of viral hemorrhagic septicemia (VHS), which outbreaks at a lower WT (< $18^{\circ}C$), could be shorter than the current infectious period. Thermal stress in fish causes reductions in growth and immunocompetence; thus, increases in summer WT can lead to the development of new viral diseases. WT has a strong influence on fish population dynamics; therefore, entry of new viruses and changes in the prevalence of infection can be expected if carrier fishes are introduced or migrate to Korean waters.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.317-320
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• 2015

H3N8 equine influenza virus (EIV) causes respiratory diseases in the horse population, and it has been demonstrated that EIV can transmit into dogs owing to its availability on receptors of canine respiratory epithelial cells. Recently, we isolated H3N8 EIV from an EIV-vaccinated horse that showed symptoms of respiratory disease, and which has a partially truncated nonstructural gene (NS). However, it is not clear that the NS-truncated EIV has an ability to cross the host species barrier from horses to dogs as well. Here, we experimentally infected the NS-truncated H3N8 EIV into dogs, and monitored their clinical signs and viral load in respiratory organs to determine the virus's transmissibility.

• Korean Journal of Veterinary Research
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• v.55 no.4
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• pp.227-232
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• 2015

Akabane and bovine ephemeral fever (BEF) viruses cause vector-borne diseases. In this study, inactivated Akabane virus (AKAV)+Bovine ephemeral fever virus (BEFV) vaccines with or without recombinant vibrio flagellin (revibFlaB) protein were expressed in a baculovirus expression system to measure their safety and immunogenicity. Blood was collected from mice, guinea pigs, sows, and cattle that had been inoculated with the vaccine twice. Inactivated AKAV+BEFV vaccine induced high virus neutralizing antibody (VNA) titer against AKAV and BEFV in mice and guinea pigs. VNA titers against AKAV were higher in mice and guinea pigs immunized with the inactivated AKAV+BEFV vaccine than in animals inoculated with vaccine containing revibFlaB protein. Inactivated AKAV+BEFV vaccine elicited slightly higher VNA titers against AKAV and BEFV than the live AKAV and live BEFV vaccines in mice and guinea pigs. In addition, the inactivated AKAV+BEFV vaccine was safe, and induced high VNA titers, ranging from 1 : 64 to 1 : 512, against both AKAV and BEFV in sows and cattle. Moreover, there were no side effects observed in any treated animals. These results indicate that the inactivated AKAV+BEFV vaccine could be used in cattle with high immunogenicity and good safety.

• Journal of Microbiology and Biotechnology
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• v.25 no.11
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• pp.1960-1965
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• 2015

Rabbit hemorrhagic disease virus (RHDV) is highly contagious and often causes fatal disease that affects both wild and domestic rabbits of the species Oryctolagus cuniculus. A highly pathogenic RHDV variant (RHDVa) has been circulation in the Korean rabbit population since 2007 and has a devastating effect on the rabbit industry in Korea. A highly pathogenic RHDVa was isolated from naturally infected rabbits, and the gene encoding the VP60 protein was cloned into a baculovirus transfer vector and expressed in insect cells. The hemagglutination titer of the Sf-9 cell lysate infected with recombinant VP60 baculovirus was 131,072 units/50 μl and of the supernatant 4,096 units/50 μl. Guinea pigs immunized twice intramuscularly with a trial inactivated RHDVa vaccine containing recombinant VP60 contained 2,152 hemagglutination inhibition (HI) geometric mean titers. The 8-week-old white rabbits inoculated with one vaccine dose were challenged with a lethal RHDVa 21 days later and showed 100% survival rates. The recombinant VP60 protein expressed in a baculovirus system induced high HI titers in guinea pigs and rendered complete protection, which led to the development of a novel inactivated RHDVa vaccine.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.50 no.5
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• pp.547-552
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• 2017

The viral hemorrhagic septicemia virus (VHSV) has an extensive host range, and infects farmed and wild fish inhabiting both freshwater and marine ecosystems. Enzyme-linked immunosorbent assay (ELISA) is highly useful in diagnosing viral hemorrhagic septicemia. However, ELISA shows high, non-specific background reaction with fish antibodies. In this study, we optimized the antigen and antibody concentrations used for detecting specific antibodies in VHSV-infected olive flounder to reduce non-specific binding, and improve the sensitivity of ELISA. The results suggested that OD (optical Density) values were valid when ELISA was performed with $0.1{\mu}g/well$ of virus, involving blocking with blocking buffer (Roth, Roti-Block), 1:300-1:600 dilution with flounder antisera, and 1:1000 dilution with anti-flounder IgM and HRP-conjugated goat anti-mouse IgG for detecting the VHSV antibody in flounder sera. Furthermore, 11 different VHSV strains isolated in Korea from 2012 to 2016 were used to infect the fish. The results showed no correlation between viral pathogenicity and antibody production. This research is a basic study on the application of antibody detection in the diagnosis of viral hemorrhagic septicemia in the olive flounder.

• Korean Journal of Veterinary Research
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• v.63 no.4
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• pp.37.1-37.7
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• 2023

Canine respiratory coronavirus (CRCoV) is a significant pathogen that causes respiratory diseases in dogs, collectively known as a canine infectious respiratory disease. The virus is highly contagious and exhibits high seroprevalence worldwide. Currently, bovine coronavirus (BCoV) enzyme-linked immunosorbent assay (ELISA) kits are used to detect CRCoV antibodies. However, BCoV-ELISA kits cannot differentiate between infections caused by BCoV and those caused by CRCoV. In this study, we evaluated the hemagglutination inhibition (HI) test for CRCoV by comparing it with the virus neutralization (VN) test. Subsequently, we evaluated the seroprevalence of CRCoV in 383 dog serum samples collected from South Korea utilizing the HI test. The HI test for CRCoV showed a strong correlation with the VN test (R = 0.83, p < 0.001). The analysis of seroprevalence revealed that 52.2% (95% confidence interval [CI], 47.2%-57.1%) of the Korean dog serum samples were positive. The seroprevalence exhibited varied with age, with a positivity rate of 43.9% in dogs under 1 year of age and 66.7% in dogs aged 3 to 5 years (odds ratio, 2.54; 95% CI, 1.43-4.59). In conclusion, the HI test to monitor CRCoV antibody proved to be closely related to the VN test. Furthermore, over half of the dogs in Korea tested positive for CRCoV antibodies. These findings contribute to a better understanding of the sero-epidemiology of CRCoV.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.7
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• pp.3281-3285
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• 2012

Objectives: To evaluate the clinicopathologic correlation and prognostic value of HPV18 DNA viral load in patients with early-stage cervical neuroendocrine carcinoma (NECA). Methods: Formalin-fixed, paraffin-embedded tissue of cervical NECA patients with known HPV18 infection and clinicopathologic data including follow-up results were collected. The HPV18 DNA load was assessed with quantitative PCR targeting the HPV18 E6E7 region. Results: Twenty-one patients with early-stage (IB-IIA) cervical NECA were identified. HPV18 DNA viral load ranged from 0.83 to 55,174 copies/cell (median 5.90). Disease progression, observed in 10 cases (48%), was not significantly associated with any clinicopathologic variables. However, the group of patients with progressive disease tended to have a higher rate of pelvic lymph node metastasis (50% versus 9%, p=0.063) and a lower median value of HPV18 DNA viral load (4.37 versus 8.17 copies/cell, p=0.198) compared to the non-recurrent group. When stratified by a cut-off viral load value of 5.00 copies/cell, the group of patients with viral load ${\leq}5.00$ copies/cell had a significantly shorter disease-free survival than the group with viral load >5.00 copies/cell (p=0.028). The group with a lower viral load also tended to have a higher rate of disease progression (75% versus 31%, p=0.080). No significant difference in the other clinicopathologic variables between the lower and higher viral load groups was identified. Conclusion: HPV18 DNA viral load may have a prognostic value in patients with early-stage NECA of the cervix. A low viral load may be predictive of shortened disease-free survival in these patients.