• IMMUNE NETWORK
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• v.7 no.2
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• pp.66-74
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• 2007

Background: The genus Flavivirus consists of many emerging arboviruses, including Dengue virus (DV), Japanese encephalitis virus (JEV) and West Nile virus (WNV). Effective preventive vaccines remain elusive for these diseases. Mice are being increasingly used as the animal model for vaccine studies. However, the pathogenic mechanisms of these viruses are not clearly understood. Here, we investigated the interaction of DV and JEV with murine bone marrow-derived dendritic cells (bmDC). Methods: ELISA and FACS analysis were employed to investigate cytokine production and phenotypic changes of DCs obtained from bone marrow following flavivirus infection. Results: We observed that these viruses altered the cytokine profile and phenotypic markers. Although both viruses belong to the same family, JEV-infected bmDC produced anti-inflammatory cytokine (IL-10) along with pro-inflammatory cytokines, whereas DV infection induced production of large amounts of pro-inflammatory cytokines (IL-6 and TNF-${\alpha}$) and no IL-10 from murine bmDCs. Both flaviviruses also up-regulated the expression of co-stimulatory molecules such as CD40, CD80 and CD86. JEV infection led to down-regulation of MHC II expression on infected bmDCs. We also found that cytokine production induced by JEV and DV is MyD88-dependent. This dependence was complete for DV, as cytokine production was completely abolished in the absence of MyD88. With regard to JEV, the absence of MyD88 led to a partial reduction in cytokine levels. Conclusion: Here, we demonstrate that MyD88 plays an important role in the pathogenesis of flaviviruses. Our study provides insight into the pathogenesis of JEV and DV in the murine model.

• IMMUNE NETWORK
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• v.12 no.2
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• pp.48-57
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• 2012

Acute viral encephalitis caused by neurotrophic viruses, such as mosquito-borne flaviviruses, is an emerging and re-emerging disease that represents an immense global health problem. Considerable progression has been made in understanding the pathogenesis of acute viral encephalitis, but the immune-pathological processes occurring during the progression of encephalitis and the roles played by various molecules and cellular components of the innate and adaptive systems still remain undefined. Recent findings reveal the significant contribution of Toll-like receptors (TLRs) and regulatory $CD4^+$ T cells in the outcomes of infectious diseases caused by neurotrophic viruses. In this review, we discuss the ample evidence focused on the roles of TLRs and $CD4^+$ helper T cell subsets on the progression of acute viral encephalitis. Finally, we draw attention to the importance of these molecules and cellular components in defining the pathogenesis of acute viral encephalitis, thereby providing new therapeutic avenues for this disease.

• Proceedings of the Korea Contents Association Conference
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• 2017.05a
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• pp.109-110
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• 2017

본 연구에서는 2016년 전 세계에 공포를 안겼던 지카 바이러스(Zika virus)와 최근 아열대성 기후의 확대로 인해 향후 대유행이 예상되는 뎅기 바이러스(Dengue virus)의 구별 진단 방법에 대해 논의하고자 한다. 두 바이러스는 모두 플라비바이러스 속(Flavivirus genus)에 해당되며, 동일한 단백질 도메인(domain)으로 구성되어 있다. 본 연구에서는 여러 도메인 중에서도 진단에 유리하다고 판단되는 비구조단백질 1(NS1, non-structural protein 1)을 선정하였으며, UniProt (Universal Protein Resource) 데이터베이스를 활용하여 지카 바이러스와 뎅기 바이러스의 비구조단백질 1의 아미노산 서열을 상호 비교 분석 하였다. 더 나아가 IEDB (Immune Epitope Database) 데이터베이스를 활용하여 비구조단백질 1의 아미노산 중, 진단에 용이한 에피토프로 예상되는 5개의 후보를 도출하였다. 최종적으로 후보군으로부터 지카 바이러스와 뎅기 바이러스를 구별하여 진단할 수 있다고 판단되는 에피토프(펩타이드)를 제안하였다.

• Proceedings of the Korea Contents Association Conference
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• 2017.05a
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• pp.297-298
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• 2017

플라비바이러스(Flavivirus)는 모기와 같은 곤충을 매개로 하여 인체에 감염된다고 잘 알려져 있다. 그 대표적인 예로 지카 바이러스(Zika virus), 뎅기 바이러스(Dengue virus), 황열 바이러스(Yellow fever virus), 일본 뇌염 바이러스(Japanese encephalitis virus) 등을 들 수 있다. 본 연구에서는 생물정보학을 기반으로 인체 감염 주요 플라비바이러스인 지카 바이러스, 뎅기 바이러스. 황열 바이러스, 일본 뇌염 바이러스의 총 4종류 플라비바이러스에 공통적으로 적용 가능한 펩타이드 백신 후보를 제시하고자 한다. 먼저 UniProt (The Universal Protein Resource)의 유전자 서열정보를 이용하여 4종류의 바이러스가 가진 단백질 중 백신으로써 적합한 단백질을 선정하였다. 선정된 단백질의 아미노산 서열정보를 바탕으로 IEDB (Immune Epitope Database And Analysis Resource)를 활용한 에피토프(epitope) 분석을 통해 에피토프로 작용하는 4 종류 바이러스의 공통적인 서열을 도출하였다.

• Journal of Biosystems Engineering
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• v.42 no.3
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• pp.217-226
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• 2017

Purpose: Aedes aegypti and Aedes albopictus are notorious disease vectors that spread various viruses including dengue, yellow fever, chikungunya, and Zika. Recent Zika virus outbreaks were carried by Ae. aegypti, raising awareness about the perils of its global distribution. Because Ae. albopictus is spread throughout South Korea and can carry the same viruses as Ae. aegypti, monitoring potential distributions of Ae. albopictus and Ae. aegypti is necessary. Methods: In this study, the potential distributions of Ae. albopictus and Ae. aegypti in South Korea were modeled using CLIMEX software, and changes in response to climate change were predicted. Results: The results indicated that the climatic suitability for Ae. albopictus was consistently high, while occurrence of Ae. aegypti was only predicted for Jeju Island in 2080. Conclusions: The results provide basic information for preventing the invasion of Ae. aegypti, and consequent interactions between Ae. aegypti and Ae. albopictus, which may cause severe outbreaks of dangerous diseases.

• Biomolecules & Therapeutics
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• v.26 no.3
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• pp.242-254
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• 2018

Defensins are antimicrobial peptides that participate in the innate immunity of hosts. Humans constitutively and/or inducibly express ${\alpha}$- and ${\beta}$-defensins, which are known for their antiviral and antibacterial activities. This review describes the application of human defensins. We discuss the extant experimental results, limited though they are, to consider the potential applicability of human defensins as antiviral agents. Given their antiviral effects, we propose that basic research be conducted on human defensins that focuses on RNA viruses, such as human immunodeficiency virus (HIV), influenza A virus (IAV), respiratory syncytial virus (RSV), and dengue virus (DENV), which are considered serious human pathogens but have posed huge challenges for vaccine development for different reasons. Concerning the prophylactic and therapeutic applications of defensins, we then discuss the applicability of human defensins as antivirals that has been demonstrated in reports using animal models. Finally, we discuss the potential adjuvant-like activity of human defensins and propose an exploration of the 'defensin vaccine' concept to prime the body with a controlled supply of human defensins. In sum, we suggest a conceptual framework to achieve the practical application of human defensins to combat viral infections.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• v.23 no.6
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• pp.539-547
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• 2020

Purpose: Pediatric acute liver failure (PALF) is a serious condition; however, data on PALF in developing countries are sparse, particularly concerning molecular diagnosis and liver transplantation (LT). This study aimed to determine the causes, outcomes, and prognostic factors of PALF. Methods: We retrospectively reviewed the medical records of children (age <15 years) with PALF diagnosed using the American Association for the Study of Liver Diseases criteria at our center from 2011 to 2016. The collected data included laboratory results, complications, outcomes, and potential factors associated with death and LT. Results: We included a total of 27 patients, with a median age of 2 years (interquartile range, 3 months to 4 years). Viral infection was the most common etiology (n=8, 30%), predominantly dengue infection (n=4). A total of 16 patients (59%) died and 11 patients survived (3 patients with LT). The prognostic factors associated with death or LT requirement were grade IV hepatic encephalopathy (p<0.01), hypotension (p=0.02), gastrointestinal bleeding (p=0.03), increased intracranial pressure (p=0.04), and higher peak serum lactate level (p=0.01). Peak serum lactate ≥6 mmoL/L had a sensitivity of 79% and a specificity of 88% for predicting mortality or the necessity of LT. Conclusion: Viral infection was the most common cause of PALF. The mortality rate remained high, and a considerable number of patients required LT. In addition to several clinical factors, peak serum lactate could be a potential marker for predicting poor outcomes in PALF.

• Genomics & Informatics
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• v.14 no.3
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• pp.104-111
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• 2016

Zika virus (ZIKV) is a mosquito borne pathogen, belongs to Flaviviridae family having a positive-sense single-stranded RNA genome, currently known for causing large epidemics in Brazil. Its infection can cause microcephaly, a serious birth defect during pregnancy. The recent outbreak of ZIKV in February 2016 in Brazil realized it as a major health risk, demands an enhanced surveillance and a need to develop novel drugs against ZIKV. Amodiaquine, prochlorperazine, quinacrine, and berberine are few promising drugs approved by Food and Drug Administration against dengue virus which also belong to Flaviviridae family. In this study, we performed molecular docking analysis of these drugs against nonstructural 3 (NS3) protein of ZIKV. The protease activity of NS3 is necessary for viral replication and its prohibition could be considered as a strategy for treatment of ZIKV infection. Amongst these four drugs, berberine has shown highest binding affinity of -5.8 kcal/mol and it is binding around the active site region of the receptor. Based on the properties of berberine, more similar compounds were retrieved from ZINC database and a structure-based virtual screening was carried out by AutoDock Vina in PyRx 0.8. Best 10 novel drug-like compounds were identified and amongst them ZINC53047591 (2-(benzylsulfanyl)-3-cyclohexyl-3H-spiro[benzo[h]quinazoline-5,1'-cyclopentan]-4(6H)-one) was found to interact with NS3 protein with binding energy of -7.1 kcal/mol and formed H-bonds with Ser135 and Asn152 amino acid residues. Observations made in this study may extend an assuring platform for developing anti-viral competitive inhibitors against ZIKV infection.

• Entomological Research
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• v.48 no.5
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• pp.439-447
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• 2018

Adult mosquito surveillance was conducted from 2013 through 2014 at four cattle sheds, a wild bird refuge, and two residential areas located in Gyeongnam Province in the Republic of Korea. Adult mosquitoes were collected in black light traps from April 1, through November 30. Mosquito surveillance was conducted to figure out population densities of vector mosquitoes, possibly invaded mosquitoes and identify various virus infections at the selected sites. A total of 107,466 females comprising 14 species and 7 genera were collected from 2013 to 2014. The most common species collected were Culex tritaeniorhynchus Giles (63.8%), Anopheles sinensis s.l. (18.9%), Aedes vexans nipponii (Theobald) (7.7%), and Culex pipiens Coquillett (5.1%). Trap indices (TIs) varied widely for species over their range, due to geographical distribution and degree of association with rural and urban communities. The most collected An. sinensiss.l. and Cx. tritaeniorhynchus appeared at a cow shed in Hapcheon (TI 347.5) and a pigsty in Daejeo-1-dong, Busan (TI 1,040.8), respectively, due in part to their situation near breeding sites such as rice paddies. The bi-weekly population densities for mosquito species were variable for each of the years, apparently as a result of variable annual weather conditions. None of the mosquito species collected tested for the flavivirus including Japanese Encephalitis Virus, West Nile Virus, Dengue Virus, and Zika Virus infections by polymerase chain reaction (PCR) assay were positive.

• Parasites, Hosts and Diseases
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• v.57 no.3
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• pp.283-290
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• 2019

A rapid diagnostic test (RDT) kit was developed to detect non-structural protein 1 (NS1) of yellow fever virus (YFV) using monoclonal antibody. NS1 protein was purified from the cultured YFV and used to immunize mice. Monoclonal antibody to NS1 was selected and conjugated with colloidal gold to produce the YFV NS1 RDT kit. The YFV RDTs were evaluated for sensitivity and specificity using positive and negative samples of monkeys from Brazil and negative human blood samples from Korea. Among monoclonal antibodies, clones 3A11 and 3B7 proved most sensitive, and used for YFV RDT kit. Diagnostic accuracy of YFV RDT was fairly high; Sensitivity was 0.0% and specificity was 100% against Dengue viruses type 2 and 3, Zika, Chikungunya and Mayaro viruses. This YFV RDT kit could be employed as a test of choice for point-of-care diagnosis and large scale surveys of YFV infection under clinical or field conditions in endemic areas and on the globe.