• Korean Journal of Veterinary Research
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• v.48 no.2
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• pp.153-159
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• 2008

Newcastle disease virus (NDV) is the causative agent of a highly contagious and devastating Newcastle disease of poultry. A NDV (isolate DK1/07) was isolated from apparently healthy wild spot-billed ducks (Anas poecilorhyncha) captured at upper branch of the SapGyo Creek in Chungbuk province, Korea during early 2007. The DK1/07 isolate of minimum chicken embryo lethal dose killed all SPF chicken embryos within 60 h. The cleavage site of the F protein possessed the amino acid sequence $^{112}R-R-Q-K-R-F^{117}$, which is a motif characteristic of virulent NDV strains. The F protein-based phylogenetic analysis revealed that the DK1/07 duck isolate was included in the cluster of genotype VIId and most closely related to recent NDV isolates obtained from chicken farms in Korea. Epidemiological importance of virulent NDV from wild duck is discussed.

• Journal of Veterinary Clinics
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• v.28 no.1
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• pp.113-121
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• 2011

Foot-and-mouth disease (FMD) is a severe vesicular disease of cloven-hoofed animals including domesticated ruminants and pigs. Acute clinical signs may be mild in sheep and goats but are associated with lameness in pigs and mouth lesions with vesicles in cattle. The required condition for a successful pathogen appears to be the ability to counteract both the host innate and adaptive immune response. FMD virus (FMDV) inhibits the induction of antiviral molecules and interferes with the secretory pathway in the infected cell. The surface expression of Major Histocompatibility Complex (MHC) class I molecules is reduced in infected cells. Thus, the ability of the host to recognize and eliminate virus infected cells is decreased. Furthermore, FMDV infection results in a rapid, but transient lymphopenia, reducing the number of T and B cells, and affecting T cell function. The virus appears to premature apoptosis-mediated cell death because it has a very short replication cycle and is able to rapidly produce large amounts of virus. FMDV engages the host protective response at multiple steps to ensure its effective replication and pathogenesis. This review describes the recent pathological and immunological studies to overcome the powerful abilities of FMDV to counteract defense mechanism of host.

• Asian-Australasian Journal of Animal Sciences
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• v.26 no.4
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• pp.588-595
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• 2013

Mesenchymal stem cells (MSCs) are often known to have a therapeutic potential in the cell-mediated repair for fatal or incurable diseases. In this study, canine umbilical cord MSCs (cUC-MSCs) were isolated from umbilical cord matrix (n = 3) and subjected to proliferative culture for 5 consecutive passages. The cells at each passage were characterized for multipotent MSC properties such as proliferation kinetics, expression patterns of MSC surface markers and self-renewal associated markers, and chondrogenic differentiation. In results, the proliferation of the cells as determined by the cumulative population doubling level was observed at its peak on passage 3 and stopped after passage 5, whereas cell doubling time dramatically increased after passage 4. Expression of MSC surface markers (CD44, CD54, CD61, CD80, CD90 and Flk-1), molecule (HMGA2) and pluripotent markers (sox2, nanog) associated with self-renewal was negatively correlated with the number of passages. However, MSC surface marker (CD105) and pluripotent marker (Oct3/4) decreased with increasing the number of subpassage. cUC-MSCs at passage 1 to 5 underwent chondrogenesis under specific culture conditions, but percentage of chondrogenic differentiation decreased with increasing the number of subpassage. Collectively, the present study suggested that sequential subpassage could affect multipotent properties of cUC-MSCs and needs to be addressed before clinical applications.

• Microbiology and Biotechnology Letters
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• v.44 no.3
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• pp.383-390
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• 2016

Mesenchymal stem cells (MSCs) are multipotent stem cells that can be differentiated into a variety of cell types, including adipocytes, osteoblasts, chondrocytes, β-pancreatic islet cells, and neuronal cells. MSCs have been reported to exhibit immunomodulatory effects in many diseases. Many studies have reported that MSCs have distinct roles in modulating inflammatory and immune responses by releasing bioactive molecules. Exosomes are cell-derived vesicles present in biological fluids, including the blood, urine, and cultured medium of cell cultures. In this study, we investigated the immunomodulatory effects of mouse adipose tissue-derived MSCs (mAD-MSCs), cultured medium (MSC-CM) of mAD-MSCs, and mAD-MSC-derived exosomes (MSC-Exo) on lipopolysaccharide (LPS)-induced RAW 264.7 cells. We observed that the expression levels of IL-1β, TNF-α, and IL-10 were significantly increased in LPS-stimulated RAW 264.7 cells compared to those in LPS-unstimulated RAW 264.7 cells. Additionally, these values were significantly (p < 0.05) decreased in mAD-MSCs-RAW 264.7 cell co-culture groups, MSC-CM-treated groups, and MSC-Exo-treated groups. MSCs can modulate the immune system in part by secreting cytokines and growth factors. We observed that immunomodulatory factors such as IL-1β, TNF-α, and IL-10 were secreted by mAD-MSCs under co-culturing conditions of mAD-MSCs with activated RAW 264.7 cells. In addition, mAD-MSC-derived exosomes exhibited similar immunomodulatory effects in activated RAW 264.7 cells. Therefore, our results suggest that mAD-MSCs have an immunomodulatory function through indirect contact.

• Korean Journal of Veterinary Service
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• v.36 no.3
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• pp.151-155
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• 2013

Since a large number of Akabane and bovine ephemeral fever (BEF) infection occurred in the southern part of Korea in 2010, recent information about seroprevalence of Akabane virus (AKAV) and bovine ephemeral fever virus (BEFV) has been required for preventing both diseases. In this study, serological assay against AKAV and BEFV using virus neutralization assay was conducted using 1,743 bovine sera collected from Namwon, Miryang, Yeongju and Uljin which located in Southern part of Korea from March to May in 2012. The overall seropositive rates for AKAV and BEFV were found to be 49.8% and 1.2%, respectively. The regional distribution of seroprevalence for AKAV ranged from 18.1% to 63.7%. Seroprevalences of AKAV were 63.7% in Miryang, 62.3% in Uljin, 50.7% in Namwon, and 18.1% in Yeongju. The seropositive rates for AKAV in southern part of Korea were higher than the annual average at the national level. On the other hand, seropositive rates of BEFV in four regions were from 0.3 to 3.1%. In detail, regional seroprevalences were 3.1% in Miryang, 2.0% in Uljin, and 1.7% in Yeongju, and 0.3% in Namwon. Even only one year after massive outbreaks, overall seropositive rates were very low, similar to the annual average at the nation level. This result indicates that many number of cattle infected with BEFV may be replaced by new born calf or cattle in farm may not be immunized with vaccines. To prevent another epidemic, a national wide warning should be issued and more aggressive control measure must be implied. Recent global warming phenomenon could lead to more vigorous activity of haematophagous vectors and it is possible that arboviral diseases such as AKAV and BEFV are increased. Therefore, continuous sero-monitoring and extensive vaccination combined with control of haematophagous vectors are important to effectively prevent and control diseases caused by AKAV and BEFV.

• Korean Journal of Veterinary Research
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• v.60 no.1
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• pp.25-32
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• 2020

Natural killer (NK) cells play have a crucial role in the early phase of immune responses against various pathogens. We compared characteristics of canine NK cells against two canine mammary carcinoma cell lines, REM134 and CF41.Mg. REM134 showed higher expression of progesterone receptor, proliferative cell nuclear antigen, Ki67, multiple drug resistance, Bmi-1, c-myc, E-cadherin, and human epidermal growth factor receptor type-2 than that of CF41.Mg. For specific expansion and activation of NK cells, we isolated CD5 negative cells from canine peripheral blood mononuclear cells and co-cultured K562 cells in the presence of interleukin (IL)-2, IL-15, and IL-21 for 21 days. As a result, we found that expression markers of activated NK cells such as NKp30, NKp44, NKp46, NKG2D, CD244, perforin, granzyme B, and tumor necrosis factor alpha were highly upregulated. In addition, we found there was upregulated production of interferon gamma of activated NK cells against target cells such as REM134 and CF41.Mg. Specifically, we observed that cytotoxicity of NK cells against target cells was more sensitively reacted to CF41.Mg than REM134. Based on the results of this study, we recommend the development of an experimental application of CF41Mg, which has not been reported in canine mammary carcinoma research.

• Korean Journal of Veterinary Research
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• v.43 no.3
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• pp.449-456
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• 2003

The VP2 gene of aquatic birnavirus, Korean isolate (GC-1) was cloned and expressed using the baculovirus expression system. The VP2 gene and VP2 partial gene, which contained a neutralizing epitope, were constructed for recombinant transfer vectors, for baculovirus expression. The expressed recombinant proteins were confirmed by indirect immuno fluorescence antibody (IFA), SDS-PAGE and Western blot. The level of expression was checked at regular time using IFA and Western blot. To measure the neutralizing activity of recombinant proteins against GC-1 strain, the antisera against recombinant proteins were produced by using guinea pigs. The result showed that the antisera neutralized the GC-1 strain. However, the neutralizing titer was higher in antisera against the VP2 gene expressed recombinant protein than that of VP2 partial gene recombinant protein.

• Microbiology and Biotechnology Letters
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• v.46 no.3
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• pp.269-276
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• 2018

Rabies virus (RABV)-specific antibodies in animals and humans are measured using standard methods such as fluorescent antibody virus neutralization (FAVN) tests and rapid fluorescent focus inhibition tests, which are based on cell culture systems. An alternative assay that is safe and easy to perform is required for rapid sero-surveillance following mass vaccination of animals. Two purified monoclonal antibodies (4G36 and B2H17) against RABV were selected as capture and detection antibodies, respectively. A genetically modified RABV, the ERAGS strain, was propagated and concentrated by polyethylene glycol precipitation. Optimal conditions for the RABV antigen, antibodies, and serum dilution for a blocking enzymelinked immune sorbent assay (B-ELISA) were established. We evaluated the sensitivity, specificity, and accuracy of the B-ELISA using serum samples from 138 dogs, 71 raccoon dogs, and 25 cats. The B-ELISA showed a diagnostic sensitivity of 95.8-96.3%, specificity of 91.3-100%, and accuracy of 96.0-97.2% compared to the FAVN test. These results suggest that the B-ELISA is useful for sero-surveillance of RABV in dogs, raccoon dogs, and cats.

• Korean Journal of Veterinary Research
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• v.43 no.1
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• pp.121-127
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• 2003

Ornithobacterium rhinotracheale (OR) is a bacterium responsible for a respiratory disease in turkeys and chickens, and has been identified as one of the emerging respiratory bacterial pathogens. Ten cases of four hundred cases submitted to National Veterinary Research & Quarantine Service for diagnosis in 2001 and in 2002 were diagnosed as OR infection. The major clinical signs of chickens infected with OR were respiratory symptoms including sneezing, sniveling, wet eyes, and swelling of the sinus infraorbitalis at 3 to 4 weeks of age. At necropsy, gross lesions were commonly found to foamish, white, and yoghurt-like exudates in the peritonium and abdominal air sacs. Microscopically, epithelial metaplasia and proliferation of air sacs were prominant with accompaning inflammatory reactions characterized by heterophils, fibrins, and bacterial colonization. Ten field isolates were obtained from air sacs and peritonium of these affected chickens, and were identified as OR, resulted from by gram-staining, catalase, oxidase, API NE and API ZYM Kit. In additon, using a previously reported primer targeted to 16S rRNA of ORT, 784bp fragment was successfully amplified from templates extracted from the isolates and a reference strain. This report describes an occurrence of Ornithobacterium rhinotracheale infection in chickens in Korea.

• Parasites, Hosts and Diseases
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• v.53 no.4
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• pp.501-506
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• 2015

Biting midges belonging to the genus Culicoides (Diptera: Ceratopogonidae) were collected by Mosquito $Magnet^{(R)}$ and black light traps at 5 sites on Jeju-do, Republic of Korea (Korea), from May-November 2013 to determine species diversity and seasonal distribution. A total of 4,267 specimens were collected, of which 99.9% were female. The most common species was Culicoides tainanus (91.8%), followed by C. lungchiensis (7.2%) and C. punctatus (0.6%), while the remaining 4 species accounted for <0.5% of all Culicoides spp. that were collected. High numbers of C. tainanus were collected in May, followed by decreasing numbers through August, and then increasing numbers through November when surveillance was terminated. Peak numbers of C. lungchiensis were collected during September, with low numbers collected from May-August and October-November. The presence of C. lungchiensis in Korea was confirmed by morphological and molecular analyses.