• Pediatric Infection and Vaccine
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• 제25권3호
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• pp.132-140
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• 2018

목적: 뎅기바이러스 감염 환자 발생은 해외 여행이 증가함에 따라 증가하고 있다. 최근 감염 경험이 없는 사람에게 백신을 접종하면 이후 야생 뎅기바이러스 감염 시 중증 뎅기열 증상을 보일 수 있다고 연구된 바 있다. 따라서, 본 연구는 한국의 다양한 연령군에서 뎅기바이러스에 대한 혈청역학을 연구하였다. 방법: 건강한 영아 98명(2개월-1세), 청소년 152명(13-19세), 성인 90명(20-50세) 및 노인 106명(65세 이상)에서 수집한 혈청 총 446명을 대상으로 하였다. 각 연령군의 뎅기바이러스 immunoglobulin G (IgG) 항체 검사를 ELISA을 통해 측정하였다. 또한 뎅기바이러스 IgG 항체 검사에서 양성 또는 equivocal을 보이는 혈청에 한하여 일본뇌염 바이러스의 IgG 항체를 검사하였다. 결과: 총 446명 검체 중, 청소년군에서 1명(0.2%)만 뎅기바이러스 항체 검사에서 양성으로 나왔다. Equivocal은 14명(3.1%)으로, 청소년군 10명과 노인군 4명이 해당하였다. 뎅기바이러스 IgG 양성이 나온 1명에서 일본뇌염 바이러스 또한 IgG 양성으로 나왔다. 뎅기바이러스 IgG equivocal이 나온 14명에서는 일본뇌염 바이러스 IgG 양성이 6명, equivocal이 3명이었고 음성은 5명이었다. 결론: 한국인에서 뎅기바이러스에 대한 항체 보유율은 매우 낮았다. 본 연구는 향후 뎅기열 예방을 위한 보건 정책 수립에 중요한 자료가 될 수 있을 것이며 향후 지속적인 혈청면역 평가도 필요할 것이다.

• IMMUNE NETWORK
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• 제11권5호
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• pp.268-280
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• 2011

Background: Dengue virus, which belongs to the Flavivirus genus of the Flaviviridae family, causes fatal dengue hemorrhagic fever (DHF) and dengue shock syndrome (DSS) with infection risk of 2.5 billion people worldwide. However, approved vaccines are still not available. Here, we explored the immune responses induced by alternating prime-boost vaccination using DNA vaccine, adenovirus, and vaccinia virus expressing E protein of dengue virus type 2 (DenV2). Methods: Following immunization with DNA vaccine (pDE), adenovirus (rAd-E), and/or vaccinia virus (VV-E) expressing E protein, E protein-specific IgG and its isotypes were determined by conventional ELISA. Intracellular CD154 and cytokine staining was used for enumerating CD4+ T cells specific for E protein. E protein-specific CD8+ T cell responses were evaluated by in vivo CTL killing activity and intracellular IFN-${\gamma}$ staining. Results: Among three constructs, VV-E induced the most potent IgG responses, Th1-type cytokine production by stimulated CD4+ T cells, and the CD8+ T cell response. Furthermore, when the three constructs were used for alternating prime-boost vaccination, the results revealed a different pattern of CD4+ and CD8+ T cell responses. i) Priming with VV-E induced higher E-specific IgG level but it was decreased rapidly. ii) Strong CD8+ T cell responses specific for E protein were induced when VV-E was used for the priming step, and such CD8+ T cell responses were significantly boosted with pDE. iii) Priming with rAd-E induced stronger CD4+ T cell responses which subsequently boosted with pDE to a greater extent than VV-E and rAd-E. Conclusion: These results indicate that priming with live viral vector vaccines could induce different patterns of E protein-specific CD4+ and CD8+ T cell responses which were significantly enhanced by booster vaccination with the DNA vaccine. Therefore, our observation will provide valuable information for the establishment of optimal prime-boost vaccination against DenV.

• BMB Reports
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• 제33권4호
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• pp.294-299
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• 2000

Proteolytic processing of the dengue virus serotype 2 polyprotein precursor is catalyzed by a host signal peptidase and a virus encoded two-component protease consisting of the nonstructural proteins, NS2B and NS3. We expressed in Escherichia coli the NS2B, NS3(pro) and NS2B-NS3 proteins from the dengue virus type 2 strain 16681 as N-terminal fusions with a hexahistidine affinity tag under the control of the inducible trc promoter. All fusion proteins were purified to >90% purity by detergent extraction of inclusion bodies and a single step metal chelate chromatography. Proteins were refolded on-column and recovered with yields of 0.5, 6.0 and 1.0 mg/l of E. coli culture that was grown to $OD_{600}=1.0$ for NS2B, NS3(pro) and NS2B-NS3, respectively. Purified proteins gave strong signals in Western blots using $Ni^{2+}-nitrilotriacetic$ acid as a probe for the presence of the polyHis tag. During the purification process, $(His)_{6}NS2B-NS3$ was apparently not autoproteolytically cleaved at the NS2B/NS3 site.

• BMB Reports
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• 제35권2호
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• pp.206-212
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• 2002

The NS2B-NS3(pro) polyprotein segment from the dengue virus serotype 2 strain 16681 was purified from overexpressing E. coli by metal chelate affinity chromatography and gel filtration. Enzymatic activity of the refolded NS2B-NS3(pro) protease complex was determined in vitro with dansyl-labeled peptide substrates, based upon native dengue virus type 2 cleavage sites. The 12mer substrate peptides and the cleavage products could be separated by reversed-phase HPLC, and were identified by UV and fluorescence detection. All of the peptide substrates (representing the DEN polyprotein junction sequences at the NS2A/NS2B, NS2B/NS3, NS3/NS4A and NS4B/NS5 sites) were cleaved by the recombinant protease NS2B-NS3(pro). No cleavage was observed with an enzymatically inactive S135A mutant of the NS3 protein, or with a modified substrate peptide of the NS3/NS4A polyprotein site that contained a K2093A substitution. Enzymatic activity was dependent on the salt concentration. A 50% decrease of activity was observed in the presence of 0.1M sodium chloride. Our results show that the NS3 protease activity of the refolded NS2B-NS3(pro) protein can be assayed in vitro with high specificity by using cleavage-junction derived peptide substrates.

• Parasites, Hosts and Diseases
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• 제57권3호
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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.