• 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.

• Clinical and Experimental Vaccine Research
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• v.12 no.2
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• pp.97-106
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• 2023

Purpose: Rabies is a fatal but preventable disease with proper pre-exposure anti-rabies vaccination (ARV). Dogs, as household pets and strays, are the reservoir and vector of the disease, and dog bites have been associated with human rabies cases in Sri Lanka over the past few years. However, other susceptible species having frequent contact with humans may be a source of infection. One such species is sheep and immunity following ARV has never been tested in sheep reared in Sri Lanka. Materials and Methods: We have tested serum samples from sheep reared in the Animal Centre, Medical Research Institute of Sri Lanka for the presence of anti-rabies antibodies following ARV. Sheep serum samples were tested with Bio-Pro Rabies enzyme-linked immunosorbent assay (ELISA) antibody kits used for the first time in Sri Lanka and our results were verified by a seroneutralization method on cells (fluorescent antibody virus neutralization, FAVN test) currently recommended by World Organization for Animal Health and World Health Organization. Results: Sheep received annual ARV and maintained high neutralizing antibody titers in their serum. No maternal antibodies were detected in lamb around 6 months of age. Agreement between the ELISA and FAVN test, i.e., coefficient concordance was 83.87%. Conclusion: Annual vaccination in sheep has an effect on maintaining adequate protection against rabies by measurements of anti-rabies antibody response. Lambs need to be vaccinated earlier than 6 months of age to achieve protective levels of neutralizing antibodies in their serum. Introducing this ELISA in Sri Lanka will be a good opportunity to determine the level of anti-rabies antibodies in animal serum samples.

• Biomedical Science Letters
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• v.8 no.4
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• pp.269-273
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• 2002

Dengue fever (DF) is an acute febrile illness caused by dengue viruses in the family Flaviviridae, genus Flavivirus. DF has so far posed any problem in Korea, however it has been recently believed to be associated with oversea's traveler infected with dengue virus. Antibody titers of sera from DF patients against dengue virus were measured by indirect immunofluorescence assay (IFA) and plaque reduction neutralization test (PRNT), including the haematologic test. Three of patients with DF showed highly fluorescent and neutralizing antibody titers by IFA and PRNT assay. Two of them showed higher, remarkably. Meanwhile, one of them was tested and resulted in severe tirombocytopenia, elevated serum levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT) activities as well as mild leucopenia, increased monocytes and basophils and depressed lymphocytes in haematological differential count.

• Korean Journal of Veterinary Service
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• v.33 no.2
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• pp.105-111
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• 2010

Rabies virus which belongs to the genus Lyssavirus of the family Rhabdoviridae is known as a highly neurotropic virus and causes fatal encephalitis accompanied by severe neurological symptoms in almost all mammals, including humans. In this study, monoclonal antibodies (MAbs) against rabies virus were produced, characterized and applications of MAbs as diagnostic reagents were assessed Spleen and inguinal lymph node cells from Balb/c mouse immunized with purified rabies virus were fused with SP2/O myeloma cells using polyethylene glycol (PEG) and hybridoma cells producing rabies virus-specific MAbs were screened by an indirect fluorescent antibody test. A total of ten MAbs were produced against rabies virus. The protein specificity and neutralizing activity of MAbs were determined by Western blot analysis and fluorescent antibody virus neutralization test, respectively. As a result, two MAbs, 5G3 and 6H4 had specificity for nucleoprotein (N protein) and two other MAbs, 5B1 and 5C1 had neutralizing activity for rabies virus. Some MAbs recognized the rabies virus-infected bovine brain stem cells by immunohistochemistry (IHC) assay. In conclusion, it was confirmed that MAbs produced in this study were rabies virusspecific and could be used as reliable diagnostic reagents for the detection of rabies virus.

• Biomedical Science Letters
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• v.6 no.2
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• pp.141-149
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• 2000

The etiologic agents of haemorrhagic fever with renal syndrome (HFRS) in Korea are Hantaan and Seoul virus in the genus Hantavirus, family Bunyaviridae. Antibody titers of sera from HFRS patients against Hantaan virus were measured by immunofluorescent antibody technique (IFAT), enzyme-linked immunosorbent assay (ELISA), high density composite particle agglutination (HDPA) and plaque reduction neutralization test (PRNI). PRNT and nested reverse transcriptase polymerase chain reaction (nested RT-PCR) was used for serotypic differentiation of Hantaviruses against Hantaan and Seoul virus. Eight doubtful HFRS patients showed higher fluorescent, IgG ELISA, agglutination and neutralizing antibody titer by IFAT, ELISA IgG, HDPA and PRNT, respectively Five out of them showed high IgM antibody titer by IgM capture ELISA against Hantaan virus, remarkably. Fifteen HFRS patients showed higher fluorescent antibody titer by IFAT. In PRNT, 12 out of them showed high neutralizing antibody titer against HTNV, 2 against SEOV and 1 against both viruses. In nested RT-PCR using serotype specific-primer, 3 out of them showed positive against HTNV and 1 against SEOV.

• 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.31 no.4
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• pp.471-477
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• 1991

Attempts to isolate chicken anemia agent (CAA) were made by inoculating tissue homogenates into MDCC-MSBl or LSCC-1104B1 cell lines and passaging the cells serially. CAA was isolated from the liver and thymus of 11 weeks old layer chickens and from the liver of 10 weeks old broiler breeder chickens. The layer flock experienced approximately 45% mortality during 9 to 14 week of age from gangrenous dermatitis and lymphoid organs of affected chickens were severely atrophied. The broiler breeder flock experienced approximately 7% mortality during 7 to 9 weeks of age and affected birds showed lesions of colibacillosis, staphylococcal arthritis, and coccidiosis together with atrophied lymphoid organs. The isolated viruses were identified as CAA by the indirect fluorescent antibody test and virus neutralization test using CAA immune sera including one to Gifu-1 strain of CAA. The CAA isolate 89-69, when inoculated into susceptible 1 day old SPF chicks, induced anemia 14 to 16 days after inoculation. It did not induce any cytopathic effects in chicken embryo liver and chicken embryo fibroblast cell cultures. Infectivity of the isolate was not affected by the treatment of chloroform or heat ($70^{\circ}C$ for 15 minutes).

• Korean Journal of Veterinary Service
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• v.22 no.1
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• pp.43-52
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• 1999

Presently, viral isolation in the diarrheal feces can be reached by many tools such as fluorescent antibody test(FA), negative contrast electron microscopy(NCEM), virus neutralization test, cell culture, and so on. The purpose of the study was to aimed at the establishment of simplified NCEM technique which can be efficiently applied for diarrheal feces and also the understanding on prevalence of viral-induced diarrhea in calves. One hundred fourty-seven korean indigenous calves with diarrhea were examined to their feces by the modified NCEM. Among them, 98(66.7%) were confirmed to have one or more viruses in feces. The viruses detected were identified as rotavirus(33.3%), coronavirus(16.3% ), togavirus(10.2%) and herpesvirus(0.7%). Ten cases of combined viral infection were consisted of 8 with rotavirus+coronavirus, one with rotavirus+togavlrus and one with rotavirus+herpesvirus. Dirrheal types could classified by yello-wish watery(44.9a ), blood-tinged(19.7% ), white watery(17.7% ) , brownish watery(14.3%), greenish watery(3.4%) diarrhea, respectively. Yellowish watery diarrhea(66cases) was frequently included rotavirus(31.8%), coronavirus(15.2%), and togavirus(13.6%), respectively. Consequently, these results suggest that the modified NCEM is reliable and efficient diagnostic tool for detection of viruses in the diarrheal feces and many calves rearing in Chonnam province have been exposed to some enteric viral agents mainly including rotavirus and coronavirus.

• Molecules and Cells
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• v.44 no.10
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• pp.770-779
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• 2021

Transgenic Arabidopsis thaliana expressing an anti-rabies monoclonal antibody (mAb), SO57, was obtained using Agrobacterium-mediated floral dip transformation. The endoplasmic reticulum (ER) retention signal Lys-Asp-Glu-Leu (KDEL) was tagged to the C-terminus of the anti-rabies mAb heavy chain to localize the mAb to the ER and enhance its accumulation. When the inaccurately folded proteins accumulated in the ER exceed its storage capacity, it results in stress that can affect plant development and growth. We generated T₁ transformants and obtained homozygous T₃ seeds from transgenic Arabidopsis to investigate the effect of KDEL on plant growth. The germination rate did not significantly differ between plants expressing mAb SO57 without KDEL (SO plant) and mAb SO57 with KDEL (SOK plant). The primary roots of SOK agar media grown plants were slightly shorter than those of SO plants. Transcriptomic analysis showed that expression of all 11 ER stress-related genes were not significantly changed in SOK plants relative to SO plants. SOK plants showed approximately three-fold higher mAb expression levels than those of SO plants. Consequently, the purified mAb amount per unit of SOK plant biomass was approximately three times higher than that of SO plants. A neutralization assay revealed that both plants exhibited efficient rapid fluorescent focus inhibition test values against the rabies virus relative to commercially available human rabies immunoglobulins. KDEL did not upregulate ER stress-related genes; therefore, the enhanced production of the mAb did not affect plant growth. Thus, KDEL fusion is recommended for enhancing mAb production in plant systems.