• The Journal of the Korean Society for Microbiology
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• v.3 no.1
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• pp.43-49
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• 1968

Japanese encephalitis(JE) shows its explosive epidemicity in the temperate zone of Asia but little is known on the overwintering mechanism. One of the hypotheses on the overwintering mechanism is that the virus overwinters in the hibernating animals. There has been no report on the proliferation of JE virus(JEV) or antibody formation in the snakes. The purpose of this experiment is to explore the mutual relationship between JEV and snake and to clarify whether JEV proliferates and induce antibody formation in snakes. Three species of non-poisonous common snakes were employed. Precipitation test was carried out after injecting calf serum and, HI and neutralization tests were done by injecting JEV into the snakes. The gamma globulin fraction of pre- and post-injection serum were compared by paper chromatography. According to the results, precipitating antibody reaction to calf serum could be observed only at $4^{\circ}C$. It was failed to demonstrate HI antibody formation but neutralizing antibody could be detected in one of the 9 snakes. Although antibody could not be detected in test-tube, tile result of paper chromatography shows the remarkable increase of gamma globulin fraction after the injection. Above results are strongly indicating the antibody formation in the snakes.

• Proceedings of the Korea Contents Association Conference
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• 2018.05a
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• pp.347-348
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• 2018

일본 뇌염 바이러스(Japanese encephalitis virus)는 작은빨간집모기(Culex spp.)를 매개로 사람에게 감염될 수 있으며, 인체에 치명적인 질병을 유발한다. 일본 뇌염 바이러스의 혈청형(serotype)은 1종류이지만, 유전형(genotype)은 5종류(GI, GII, GIII, GIV, GV)로 분류되고 있다. 현재 일본 뇌염 바이러스 백신은 아시아 지역에서 감염 빈도가 높은 유전형 3(GIII)에 대한 백신이며, 사백신(inactivated vaccine)과 약독화 백신(attenuated vaccine)이 주로 사용되고 있다. 본 연구에서는 기존 백신의 부작용을 줄이고 한계점을 개선하기 위하여, 생물정보학 데이터베이스를 활용한 접근법을 통해 펩타이드 백신 후보군을 선별하였다. 5가지의 유전형 중에서도 감염 빈도가 가장 높은 유전형 3(GIII) 및 최근 감염빈도가 서서히 늘어나고 있어 주의가 요구되고 있는 유전형 1(GI)을 연구 대상으로 선정하였다. 여러 종류의 생물정보학 데이터베이스를 활용하여 백신으로 활용가치가 높은 것으로 보고되고 있는 외피 단백질(envelope protein)에 대한 아미노산 상동성을 분석하고, 이를 바탕으로 공통 적용이 가능한 동시에 면역원성이 높은 펩타이드 3종을 백신 후보군으로 선별하였다. 더 나아가 이들의 3차원 구조 모델링을 통해 보다 백신으로 활용 가능성이 높은 펩타이드를 최종 도출하였다.

• KOREAN POULTRY JOURNAL
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• v.36 no.7 s.417
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• pp.96-101
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• 2004

사람들이 모기를 싫어하는 이유는 많다. 모기는 사람과 가축에 각종 병원체를 옮기며, 또한 많은 스트레스를 주고, 이로 인한 정신적인 피해가 크기 때문이다. 가축에서는 가축이 수면을 제대로 취하지 못하게 하고, 질병을 일으켜서 경제적인 피해를 입히기도 한다. 모기로 인해 육계는 성장이 늦어지고, 산란계에서는 산란율이 떨어진다. 사람이 모기에 물리게 되면 간지럽고, 빨갛게 붓는 피부 알러지가 생기고, 잠잘 때 윙윙 소리를 내어 수면을 방해한다는 점, 그로 인한 불쾌감, 정신적 스트레스 등의 피해를 입는다. 그러나 무엇보다도 모기가 주는 가장 큰 피해는 각종 질병을 옮기고 다닌다는 것이다. 모기로 인해 옮겨지는 병으로는 뇌염(encephalitis), 마랄리아(malaria), 상피병(filaria), 황열병(yellow fever), 뎅기열(dengue fever) 등을 들 수 있다. 그 중에서도 국내에서 발병하는 병은 일본뇌염(Japanese encephalitis), 말라리아, 상피병 등이 알려져 있다. 가축에서 오는 모기 매개 질병은 소의 아까바네병, 유행열, 이바라기병 및 츄잔병, 아이노바이러스 감염증 등이 있고, 돼지에서는 사람에게 뇌염을 일으킬 수 있는 돼지일본뇌염이 있고 닭에서는 닭류코사이토준병이 있다.

• KSBB Journal
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• v.19 no.1
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• pp.88-92
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• 2004

The immunogenicity of investigational combined vaccine, composed of the Japanese encephalis virus(JEV) and the polysaccharide capsule(Vi) of Salmonella typhi covalently bound to tetanus toxoid(TT) was evaluated in mice. The mice immunized with combined vaccine elicited higher anti-Vi Immunoglobulin G(IgG) as well as anti-JEV IgG levels than the mice immunized with Vi-TT or JEV alone. The combined vaccine produced four-fold increase in anti-Vi IgG level than Vi-TT alone. In JEV the combined vaccine was significantly more immunogenic than JEV alone and induced six-fold increase in IgG level. Adsorption of combined vaccine onto aluminium hydroxide gel also enhanced IgG level for both Vi and JEV.

• Korean Journal of Microbiology
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• v.46 no.2
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• pp.140-147
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• 2010

Japanese encephalitis virus (JEV), a member of the mosquito-borne flaviviruses, causes epidemics of viral encephalitis in the Southeastern Asia. JEV is a small enveloped virus with a positive-sense RNA genome; the infectious virion consists of three structural proteins, namely capsid, membrane (M; a mature form of its prM precursor), and envelope proteins. Here, we investigated a role of the charged residues found at the N-terminus of the JEV M protein in virus production. Using an infectious JEV cDNA, we generated two mutant cDNAs, Mm1 and Mm2, by charged-to-alanine substitution for $E^9$ and $K^{15}K^{16}E^{17}$ residues of the M protein, respectively. By transfection of wild-type or each of the two mutant RNAs transcribed from the corresponding cDNAs, we found that Mm2, but not Mm1, had a ~3-log decrease in virus production, even though a comparable amount of all three structural proteins were produced in transfected cells. Interestingly, the prM protein expressed in Mm2 RNA-transfected cells was not recognized by the polyclonal antiserum raised against the N-terminal 44 amino acids of the wild type M protein, but reacted to the antiserum raised against the corresponding region of the mutant Mm2. Our results indicate that three charged residues ($K^{15}K^{16}E^{17}$) in JEV M protein play a role in virus production. Two polyclonal antisera specifically recognizing the wild-type or Mm2 version of the M protein would provide a useful reagent for the functional study of this protein in the virus life cycle.

• Proceedings of the Microbiological Society of Korea Conference
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• 2000.05a
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• pp.23-36
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• 2000

Japanese encephalitis virus (JEV) is the causative agent of a mosquito-borne encephalitis and is transmitted to human via persistently infected mosquito vectors. Although the virus is known to cause only acute infection, there were reports that showed neurological sequelae, latent infection in peripheral mononuclear cells, and recurrence of the disease after acute encephalitis. Innate resistance of certain cell lines, abnormal SN1 expression of the virus, and anti-apoptotic effect of cullular bcl-2 have been suggested as probable causes of JEV persistence even in the absence of defective interfering (DI) particles. Although possible involvement of DI particles in JEV persistence was suggested, neither has a direct evidence for DI presence nor its molecular characterization been made. Two questions asked in this study are whether the DI virus plays any role in JEV persistent infection if it is associated with and what type of change(s) can be made in persistently infected cells to avoid apoptosis even with the continuous virus replication, DI-free standard stock of JEV was infected in BHK-21, Vero, and SW13 cells and serial high multiplicity passages were performed in order to generate DI particles. There different-sized DI RNA species which were defective in both structural and nonstructural protein coding genes. Rescued ORFs of the DI genome maintained in-frame and the presence of replicative intermediate or replicative form RNA of the DI particles confirmed their replication competence. On the other hand, several clones with JEV persistent infection were established from the cells survived acute infections during the passages. Timing of the DI virus generation during the passages seemed coincide to the appearance of persistently infected cells. The DI RNAs were identified in most of persistently infected cells and were observed throughout the cell maintenance. One of the cloned cell line maintained the viral persistence without DI RNA coreplication. The cells with viral persistence released the reduced but continuous infectious JEV particle for up to 9 months and were refractory to homologous virus superinfection but not to heterologous challenges. Unlike the cells with acute infection these cells were devoid of characteristic DNA fragmentation and JEV-induced apoptosis with or without homologous superinfection. Therefore, the DI RNA generated during JEV undiluted serial passage on mammalian cells was shown to be biologically active and it seemed to be responsible, at least in part, for the establishment and maintenance of the JEV persistence in mammalian cells. Viral persistence without DI RNA coreplication, as in one of the cell clones, supports that JEV persistent infection could be maintained with or without the presence of DI particles. In addition, the fact that the cells with JEV persistence were resistant against homologous virus superinfection, but not against heterologous one, suggests that different viruses have their own and independent pathway for cytopathogenesis even if viral cytopathic effect could be converged to an apoptosis after all.

• Korean Journal of Veterinary Research
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• v.29 no.2
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• pp.109-114
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• 1989

The frequency of appearance of HI antibody against Japanese encephalitis virus was investigated over the three-year period 1982 through 1984. The sample population consisted of 1306 cattle in Saitama prefecture (located in central Japan), and 536 cattle in Kagoshima prefecture (located in southern Japan). During the study period, there was no significant difference in the average antibody-positive rate between cattle in Kagoshima (68.8%) and those in Saitama (65.5%). Variations in the monthly antibody-positive rate and mean monthly antibody titer in the Saitama cattle followed a mountain-like pattern with the peak observed during summer. In the Kagoshima cattle, both parameters also increased in summer and these increases persisted even in winter. The distribution of antibody-positive rate as a function of age ranged from 64.0% to 82.8% in Saitama, though no correlation was observed between these two factors. In the Kagoshima cattle, however, the antibody-positive rate increased with age as follows; the values averaged 29.4% in the one-year-old cattle group, 50.0% in the two-year-old group, 47.4% in the three-year-old group and 74.5% in the four-year-old group. There was no significant correlation between the mean antibody titer and age in either Saitama cattle (15.3~22.5) or Kagoshima cattle (20.0~32.3).

• KSBB Journal
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• v.13 no.3
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• pp.231-237
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• 1998

An attenuated Japanese encephalitis virus (JEV) clone SA-14-14-2(Vero) was obtained through successive adaptation of a primary cell adapted strain, SA-14-14-2(PDK) to Vero cell, a continuous line of monkey kidney cells. The virus titer reached above the 107 plaque forming unit (pfu) per mL of culture supernatant with 3 passages in Vero cells and was maintained close to this level in the further passages. The optimum temperature for the virus growth was $35^{\circ}C$. Growth pattern of the virus indicated that optimum time for the virus harvest is 4 days post infection and the virus accomplished rapid initial propagation even in medium containing no serum supplement. The roller bottle (RB) system and the spinner flask (SF) system using micro-carrier (Cytodex-1) for the JEV cultivation were explored. When RB, SF, and T-flask culture system were compared, there was no significant difference in virus yield. Furthermore, the results indicated that virus could be harvested multiple times from 3 days to 9 days post infection; neither severe cytopathic effect (CPE) in the infected cells nor the decrease in the titer was observed on duration of 9 days.

• Parasites, Hosts and Diseases
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• v.40 no.1
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• pp.45-54
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• 2002

Field trials evaluating selected commercially available mosquito traps variously baited with light, carbon dioxide, and/or octenol were conducted from 18-27 September 2000 in a malarious area near Paekyeon-ri (Tongil-Chon) and Camp Greaves in Paju County, Kyonggi Province, Republic of Korea. The host-seeking activity for common mosquito species, including the primary vector of Japanese encephalitis, Culex tritaeniorhynchus Giles. was determined using hourly aspirator collections from a human and propane lantern-baited Shannon trap doting hours when temperatures exceeded $15^{\circ}C$. The total number of mosquitoes and number of each species captured during the test was compared using a block design. Significant differences were observed for the total number of mosquitoes collected, such that, the Mosquito MagnetTM with octenol > Shannon trap > ABC light trap with light and dry ice > Miniature Black Light trap (manufactured by John W. Hock) $\geq$ New Jersey Trap > ABC light trap with light only. Significant differences in numbers collected among trapes were noted for several species including: Aedes vexans (Meigen), Anopheles lesteri Baisas and Hu. An. sinensis Weidemann, An. sineroides Yamada, An. yatsushiroensis Miyazaki. Culex pipiens pallets Coquillett L., Cx. orientalis Edwards and Cx. tritaeniorhynchus. Host-seeking activity for most common species showed a similar bimodal pattern. Results from these field trap evaluations can significantly enhance current vector and disease surveillance efforts especially for the primary vector of Japanese encephalitis, Cx. tritaeniorhunchus.

• Korean Journal of Microbiology
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• v.35 no.1
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• pp.82-88
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• 1999

In this study, to evaluate newly developed Japanese encephalitis (JE) vaccine candidate CJ50003, we assessed its immunogenicity along with a previously commercialized inactivated JE Biken vaccine. The CR0003 viral antigens produced in Vero cells were administered suhcutaneouly to mice either with alum-adjuvanled or free form. The ELISA titers and neutralizing (NEUV antibody titers accounting for major protective immunity in JE were determined. Mice given alum-adjuvanted vaccine had a 10 times higher antigen-specific NEUT antibody response than did those which {lad received free antigens. This NEUT antibody response was maintained until day 168 with NEUT titer more than 1:160. Even with the 0.5 ng of alum-adjuvanted antigen dose, NEUT titer was induced more than 1:10 which is considered as an evidence for seroconversion and protection. Thc mice immune sera had a similar rate of cross-reactivity against three different viral antigens, Nakayama-NlH, P3 and SA14; as determined by ELISA assay. In a mice challenge model, vaccination with the GI50003 conferred more protection than with commercialized Biken vaccine against Nakayama virus. These data demonstrated that CJ50003 vaccine candidate has an excellent prophylactic efficacy and implicated it has a strong potential for further development and commercialization.