Corrigendum: Characterizing affinity epitopes between prion protein and beta-amyloid using an epitope mapping immunoassay

Due to an author error the National Research Foundation of Korea Grant Number was incorrectly listed in the original online publication of this article.

Characterizing affinity epitopes between prion protein and beta-amyloid using an epitope mapping immunoassay

Cellular prion protein, a membrane protein, is expressed in all mammals. Prion protein is also found in human blood as an anchorless protein, and this protein form is one of the many potential sources of misfolded prion protein replication during transmission. Many studies have suggested that beta-amyloid1-42 oligomer causes neurotoxicity associated with Alzheimer's disease, which is mediated by the prion protein that acts as a receptor and regulates the hippocampal potentiation. The prevention of the binding of these proteins has been proposed as a possible preventative treatment for Alzheimer's disease; therefore, a greater understanding of the binding hot-spots between the two molecules is necessary. In this study, the epitope mapping immunoassay was employed to characterize binding epitopes within the prion protein and complementary epitopes in beta-amyloid. Residues 23-39 and 93-119 in the prion protein were involved in binding to beta-amyloid1-40 and 1-42, and monomers of this protein interacted with prion protein residues 93-113 and 123-166. Furthermore, beta-amyloid antibodies against the C-terminus detected bound beta-amyloid1-42 at residues 23-40, 104-122 and 159-175. beta-Amyloid epitopes necessary for the interaction with prion protein were not determined. In conclusion, charged clusters and hydrophobic regions of the prion protein were involved in binding to beta-amyloid1-40 and 1-42. The 3D structure appears to be necessary for beta-amyloid to interact with prion protein. In the future, these binding sites may be utilized for 3D structure modeling, as well as for the pharmaceutical intervention of Alzheimer's disease.

Immunogenicity and Protective Effectiveness of Japanese Encephalitis Vaccine: A Prospective Multicenter Cohort Study / 소아감염

PURPOSE: This study aimed to study the antibody response of Japanese encephalitis vaccination in children using different kinds of vaccines (inactivated vaccine, live attenuated vaccine or interchanged) and evaluate the effectiveness of the vaccines to provide the basis of efficient immunization schedule of Japanese encephalitis. METHODS: Measurement of the neutralization antibody (NTAb) titers following Japanese encephalitis vaccination using different vaccines for 170 children, 2-6 year of age, who visited six university hospitals and are confirmed by immunization records. RESULTS: Among 170 children who were given primary immunization on Japanese encephalitis, 103 children were given inactivated vaccine, 64 children were given live attenuated vaccine and 3 children were given interchangeably. NTAb titers were more than 1:10 in all children of three groups. The geographic mean antibody titer was 322 in inactivated vaccine group and 266 in live attenuated vaccine group. However, there was no significant difference between two groups. In both groups, the NTAb titer showed the peak at 1-4 months after the third immunization and declined. The NTAb titers of three children who were given two kinds of vaccines alternately were 1:135, 1:632, and 1:2511, respectively. CONCLUSION: According to the results of this study in children younger than 6 years old, there is no significant difference in effectiveness between inactivated and live attenuated vaccines. However, further studies for the changes of antibody titers for a longer period of time on larger population are required.

Yellow Fever Vaccine-associated Viscerotropic Disease / 대한내과학회지

This report describes a case of yellow fever vaccine-associated viscerotropic disease (YEL-AVD) that occurred after vaccination in a 23-year-old male. Seven days after vaccination, our patient presented with fever, myalgia, and nausea. The IgM enzyme-linked immunosorbent assay (ELISA) for yellow fever virus was positive. After a 24 day hospitalization, he recovered and was discharged. Yellow fever is a viral hemorrhagic febrile illness caused by a flavivirus and transmitted by mosquitoes. The clinical presentation ranges from a mild febrile illness to a serious infection, leading to hepatic and renal failure, myocardial injury, hemorrhage, and shock, with a case fatality rate of 20-30%. Because yellow fever is a potentially fatal disease, vaccination is encouraged for people traveling to high-risk areas. Although considered a safe vaccine, severe adverse reactions have been reported. In 2001, rare, but severe, acute viscerotropic disease following vaccination was first described. We report the case of a 23-year-old male with fever and hepatitis following vaccination with 17D yellow fever vaccine.

Prevalence of tick-borne encephalitis virus in ticks from southern Korea

The prevalence of tick-borne encephalitis virus (TBEV) in southern Korea was determined by collecting ticks using tick drags. A total of 4,077 of 6,788 ticks collected were pooled (649 pools) according to collection site, species, and developmental stage and assayed for TBEV. The TBEV protein E and NS5 gene fragments were detected using RT-nested PCR in six pools of nymphs collected from Jeju Island (2,491 ticks). The minimum field detection rates for TBEV were 0.17% and 0.14% for Haemaphysalis longicornis and Haemayphysalis. flava nymphs, respectively. The 252 bp NS5 and 477 bp protein E gene amplicons were sequenced. Phylogenetic analysis showed that the NS5 and protein E genes of the Jeju strain were clustered with Western subtype (98.0% and 99.4% identity, respectively). The Western subtype of TBEV is endemic in Korea, including Jeju Island. The study of vector and zoonotic host susceptibility to TBEV is required to better understand its potential impact on public health.

Meningitis following vaccination with yellow-fever vaccine / 대한내과학회지

Yellow fever is the original viral hemorrhagic fever (VHF), a pansystemic viral sepsis with viremia, fever, prostration, hepatic, renal, and myocardial injury, hemorrhage, shock, and high lethality. Yellow fever was one of the most feared lethal diseases before the development of an effective vaccine. Yellow fever (YF) can be prevented by an attenuated vaccine. The yellow-fever 17D vaccine developed in the 1930s has been regarded as one of the most successful live attenuated vaccines, with few side effects or adverse events. The adverse effects associated with yellow-fever vaccine are generally mild and include headache, myalgia, and low-grade fever. Recently, however, some cases of severe neurologic disease and multi-organ system disease have been described in individuals who received yellow-fever vaccine. We report the case of a 39-year-old female with meningitis following vaccination with 17D yellow-fever vaccine.

Seroepidemiological Characteristics of Haemorrhagic Fever with Renal Syndrome from 1996 to 2005 in Korea

Haemorrhagic fever with renal syndrome (HFRS) caused by Hantaan viruses has been one of the principal acute febrile disease in Korea. To analysis the sero-epidemiological patterns of HFRS, 4,177 patient sera of acute febrile illness submitted for serological assay to National Institute of Health from Community Health Centers, Institutes of Health and Environment and hospitals from 1996 to 2005 were examined for antibodies against Hantaan virus by indirect immunofluorescent assay (IFA). Serum samples with greater than 1:32 antibody titer were considered positive. The results were analyzed seroepidemiologically by annual, sexual, seasonal, age and regional distribution of HFRS patients. Out of 4,177 serum samples tested, 1,415 samples (33.9%) were positive to Hantaan virus. The ratio of males (48.2%, 682/1,415) to females (38.2%, 541/1,415) was 1.3:1. Seasonal incidence showed that 69.5% (985/1,415) of cases occurred from October to December, resulting with higher prevalence in November (41.3%, 584/1,415). Regionally, seropositive rates of samples collected in Gyenggi, Gangwon and Chungbuk were 39.9% (564/1,415), 19.3% (274/1,415) and 8.5% (120/1,1415), respectively. Age distributions of seropositive of HFRS were detected from 20 to 79 years (78%).

Positive Rate of Antibody Against Dengue Virus for Korean Who Traveled to Dengue Epidemic Area / 감염과화학요법

BACKGROUND: Recently, dengue fever has increased throughout tropical regions and emerged as the most important vector borne viral disease in human. 4 serotypes of viruses are circulating concurrently in these regions and thus it may be anticipated to increase risk of dengue hemorrhagic fever. Even though dengue fever is still not endemic in Korea, it is necessary to test antibodies against dengue viruses because the number of Koreans who have visited these regions is continuously increasing. MATERIALS AND METHODS: Serum specimens from persons with suspected dengue fever had been collected. Commercial kit, immunochromatographic test (ICA), and the IgM capture enzyme-linked immunosorbent assay (MAC-ELISA) were employed for dengue fever detection in these studies. For confirmation randomized 25 specimens among total of 99 specimens were selected and compared with those results from commercial kit and IFA. RESULTS: 33 (33.3%) among 99 specimens showed positive antibody against dengue virus by commercial kit. Positive rate of traveller who have visited Indonesia, Philippines, Malaysia, Thiland was 54.5%. To compare the efficiency of test methods, 25 randomly selected specimens were tested by the MAC-ELISA and IFA simultaneously. 9 specimens showed postive results with the MAC-ELISA method whereas 13 speciments were positive with the IFA methods. CONCLUSION: Confirming the diagnosis of dengue fever with antibody against dengue virus was attempted for the first time in Korea. The results from our study indicate that establishing a national surveillance and/or laboratory diagnostic system in Korea are necessary. In addtion, antibody test strategies for national surveillance system should be carefully considered.

Positive Rate of Antibody Against Dengue Virus for Korean Who Traveled to Dengue Epidemic Area / 감염과화학요법

BACKGROUND: Recently, dengue fever has increased throughout tropical regions and emerged as the most important vector borne viral disease in human. 4 serotypes of viruses are circulating concurrently in these regions and thus it may be anticipated to increase risk of dengue hemorrhagic fever. Even though dengue fever is still not endemic in Korea, it is necessary to test antibodies against dengue viruses because the number of Koreans who have visited these regions is continuously increasing. MATERIALS AND METHODS: Serum specimens from persons with suspected dengue fever had been collected. Commercial kit, immunochromatographic test (ICA), and the IgM capture enzyme-linked immunosorbent assay (MAC-ELISA) were employed for dengue fever detection in these studies. For confirmation randomized 25 specimens among total of 99 specimens were selected and compared with those results from commercial kit and IFA. RESULTS: 33 (33.3%) among 99 specimens showed positive antibody against dengue virus by commercial kit. Positive rate of traveller who have visited Indonesia, Philippines, Malaysia, Thiland was 54.5%. To compare the efficiency of test methods, 25 randomly selected specimens were tested by the MAC-ELISA and IFA simultaneously. 9 specimens showed postive results with the MAC-ELISA method whereas 13 speciments were positive with the IFA methods. CONCLUSION: Confirming the diagnosis of dengue fever with antibody against dengue virus was attempted for the first time in Korea. The results from our study indicate that establishing a national surveillance and/or laboratory diagnostic system in Korea are necessary. In addtion, antibody test strategies for national surveillance system should be carefully considered.

Application of Hantavirus N Protein Expressed by E. coli System

Hantaan viruses cause haemorrhagic fever with renal syndrome (HFRS), resulting in severe morbidity and mortality in humans. The genome of Hantaan virus is composed of three segmented and single stranded negative sense RNA genome. In this study, we expressed nucleocapsid (N) proteins of Hantaan 76-118, Seoul 80-39 and Hantaan virus isolated in Korea (01-23) using E. coli system. These N proteins were fused with a thioredoxin protein for secretion of the expressed protein. The antigenicity of each expressed N proteins was examined in Western blot with sera from HFRS patients and normal controls. The expressed N proteins did not show any cross-reactivity with sera obtained from patients with leptospirosis and tsutsugamushi disease. These results suggest that our recombinant N proteins can be used for the development of diagnostic system to distinguish between HFRS and leptospirosis or tsutsugamushi.

Expression and Purification of Glycoprotein G1 of Hantaan Virus in E. coli System

Envelope glycoprotein 1 (G1) and glycoprotein 2 (G2) of Hantaan (HTN) virus are believed to be major viral antigens that can induce neutralizing immunity against HTN virus infection. The purpose of this study is to clone and express G1 gene in an E. coli expression system. The truncated G1 gene (amino acid residues 35 to 123) of the HTN virus strain 76-118 was amplified by polymerase chain reaction (PCR). The 0.28 kb PCR product was cloned into pCR2.1 vector and named as pCGS1. The truncated G1 gene was excised from the pCGS1 and subcloned into the BamHI and SalI sites of pGEX-4T-2 and named pGGS1. The nucleotide sequence of the 0.28 kb truncated G1 gene was determined. It is revealed four non-silent nucleotide substitutions between the published sequence of strain HTN virus strain 76-118 and our stock of HTN virus strain 76-118 (passaged several times in our laboratory). The first G1 mutation was found to constitute an A to G nucleotide substitution, giving raise to an asparagine to serine mutation at residue 64. The second G1 mutation was found to constitute an A to C nucleotide substitution, giving raise to an lysine to threonine mutation at residue 112. The third G1 mutation was found to constitute an A to C nucleotide substitution, giving raise to an lysine to threonine mutation at residue 112. The fourth G1 mutation was found to constitute an G to A nucleotide substitution, giving raise to an glutamic acid to lysine mutation at residue 117. The truncated G1 gene was expressed as a 37 kDa protein fused to glutathione-S-transferase (GST). The GST fusion protein was purified by Glutathione Sepharose 4B affinity chromatography and reacted with the sera from patients of hemorrhage fever with renal syndrome (HFRS). One of 12 serum samples from HFRS patients was reactive with the 37 kDa fusion protein strongly. Three sera reacted moderately with the fusion protein. Six sera reacted only weakly with the protein, while remaing two were non-reactive. Control sera from patients with scrub typhus leptospirosis, or negative HFRS did not react with the recombinant fusion protein.

Serologic and Genetic Characterization of Hantavirus from Apodemus Mice Captured in Kyonggi - do and Gangwon - do , 2001

Hantaan virus is widely distributed in Korea and has been known to cause hemorrhagic fever with renal syndrome (HFRS). Hantaviruses are carried by numerous rodent species throughout the world. Especially, the striped field mice, Apodemus agrarius, is natural host for Hantaan virus in Korea. In this study, a total 105 wild rodents of 3 species (101 of Apodemus agrarius, 2 of Eothenomys regulus, and 2 of Mus musculus) were trapped in Kyonggi and Gangwon provinces for April to June, 2001 to study serologic and genetic characterization. 8 Apodemus agrarius (7.9%) were immunofluorescent antibody (IFA) positive against Hantaan virus and Hantaan virus genome was found in 5 among 8 seropositive rodents. S gene of isolated Hantaan virus genome was amplified and directly sequenced. Based on 917 bases of S gene (411-1327 bases), 2001 Korean isolates showed 94.8% to 95.5% nucleotide homologies in comparison with prototype Hantaan virus 76-118 which was isolated from Apodemus agrarius in Korea, 1976. The partial M gene (1969-2240 bases) showed 94.1% to 100.0% nucleotide homologies in comparison with 76-118 strain. In phylogenetic analysis, 2001 Korean isolates made the distinct cluster. Therefore, Hantaan viruses isolated in 2001 were not significantly chinged in genetic level comparison with previous isolate from Korea.