The Japanese encephalitis virus (JEV), a member of the Flaviviridae family and Flavivirus genus, is transmitted by mosquitoes. JEV, of which some 35,000 cases are recorded every year, is a positive RNA virus. Two types of JEV vaccines have been developed to prevent the onset of encephalitis in humans, namely formalin-inactivated and liveattenuated vaccines. JEV inactivated vaccines are usually made using the Nakayama-NIH or Beijing-1 strains of the JEV virus. In this study, the immunological response to the Nakayama-NIH and Beijing-1 strains was analyzed as part of the effort to compile basic data which could lead to the selection of a suitable vaccine strain. To this end, the virus titer of Beijing-1 was found to be two-fold higher than that of Nakayama-NIH by plaque assay. Moreover, Beijing-1-induced neutralizing antibodies showed a higher level of titers when confronted by Korean JEV isolates than Nakayama-NIH-induced neutralizing antibodies (1:320 vs. 1:160, respectively). However, as a minimum ratio of 1:10 neutralizing antibody titers are required to protect against JEV infection, both strains in effect exhibited a sufficient level of neutralizing antibody titers. What's more, Beijing-1 was found to induce a somewhat higher cytotoxic T lymphocyte (CTL) response than Nakayama-NIH. Taken together, this can be taken to mean that Beijing-1 may in fact be a more effective vaccine candidate strain when it comes to inducing a high level of protective immunity against JEV infection.
Antibodies, Neutralizing* ; Asian Continental Ancestry Group* ; Culicidae ; Encephalitis ; Encephalitis Virus, Japanese* ; Encephalitis, Japanese* ; Flaviviridae ; Flavivirus ; Humans ; Lymphocytes* ; RNA Viruses ; Vaccines ; Vaccines, Inactivated ; Viral Load

Three dimensional structures of envelope protein from Korean isolates and Nakayama-NIH strain of Japanese encephalitis virus (JEV) were deduced by a computer program (HyperChem 4.0 Chemplus 1.0) based on the data of the three dimentional structure of Tick-borne encephalitis virus. In the three dimensional structure of envelope protein, neutralizing epitope and T-helper cell recognition site of C-terminal region of Korean isolates were structually similar to those of Nakayama-NIH but the N-terminal region was not. Korean JE isolates were compared with Nakayama-NIH strain by using cross-neutralization antibody test. Neutralizing activities of Korean isolates derived from guinea pigs were higher than those of Nakayama-NIH strain against Korean isolates, although the polyclonal antibody titers of Nakayama-NIH showed 1:160 to 1:640 against Korean isolates. According to the results from three dimentional structures and cross-neutralization analyses, the antigenic difference between Korean JE isolates and Nakayama-NIH strain may be dependent on structural difference of envelope protein.
Animals ; Encephalitis Virus, Japanese ; Encephalitis Viruses* ; Encephalitis Viruses, Tick-Borne ; Encephalitis* ; Guinea Pigs ; Korea*

<b>OBJECTIVEb>To study the pathogenic effect of hepatitis G virus (HGV) infection on hepatic failure.

<b>METHODSb>Using the RT-PCR and EIA techniques to detect HGV RNA and anti-HGV in sera of hepatic failure patients and compare them with their liver function and mortality rates.

<b>RESULTSb>There was no significant difference about the positive rates of HGV among acute hepatic failure, subacute hepatic failure and chronic hepatic failure groups (X(2)=2.54, P>0.05). The level of ALT in HGV-positive group was slightly lower than that in HGV-negative group. The concentration of bilirubin and globulin was higher in HGV-positive group than HGV-negative group, and the concentration of albumin in HGV-positive group was significantly lower than that in HGV-negative group (t=2.59, P<0.05). The mortality rate in HGV-positive group was significantly lower than that in HGV-negative group (X(2)=4.68, 0.01

<b>CONCLUSIONSb>The virulence of HGV is mild, and the HGV infection does not aggravate hepatic failure.

Adult ; Female ; Flaviviridae Infections ; complications ; GB virus C ; pathogenicity ; Hepatitis, Viral, Human ; complications ; Humans ; Liver Failure ; etiology ; Male ; Middle Aged

Zika virus was first isolated in from nonhuman primate in 1947. It is in the genus Flavivirus, closely related to other flavivirus like Dengue, West Nile, Yellow fever and Japanese encephalitis virus. Since 2007 epidemic in Yap island, zika virus infections had spread to the countries in Micronesia and South Pacific. In 2015, Zika virus outbreak occurred in Brazil and now more than 40 countries in American continents reported autochthonous infection. The virus is transmitted mainly by Ae. aegypti mosquito with many other Aedes mosquito species known as vector. Recently, Zika virus infection is known to cause severe neurological complications and congenital malformation. In this paper, we will review current knowledge on Zika virus history, biology, clinical characteristics and preventive method.
Aedes ; Biology ; Brazil ; Culicidae ; Dengue ; Encephalitis Virus, Japanese ; Flavivirus ; Methods ; Microcephaly ; Micronesia ; Primates ; Yellow Fever ; Zika Virus Infection* ; Zika Virus*

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.
Communicable Diseases ; Dengue Virus ; Encephalitis ; Encephalitis Virus, Japanese ; Encephalitis, Viral ; Flavivirus ; T-Lymphocyte Subsets ; T-Lymphocytes ; Toll-Like Receptors ; West Nile virus

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.
Adenoviridae ; Dengue ; Dengue Hemorrhagic Fever ; Dengue Virus ; DNA ; Enzyme-Linked Immunosorbent Assay ; Flaviviridae ; Flavivirus ; Homicide ; Humans ; Immunity, Cellular ; Immunization ; Immunoglobulin G ; Plasmids ; T-Lymphocytes ; Vaccination ; Vaccines ; Vaccinia virus

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.
Adenoviridae ; Dengue ; Dengue Hemorrhagic Fever ; Dengue Virus ; DNA ; Enzyme-Linked Immunosorbent Assay ; Flaviviridae ; Flavivirus ; Homicide ; Humans ; Immunity, Cellular ; Immunization ; Immunoglobulin G ; Plasmids ; T-Lymphocytes ; Vaccination ; Vaccines ; Vaccinia virus

<b>OBJECTIVEb>To observe the relationship between the amount of HBV DNA in serum/liver tissue and HGV infection in patients with chronic hepatitis B (CH-B) for exploring the effect of HGV infection on hepatitis B virus (HBV) replication of CH-B.

<b>METHODSb>HGV RNA in serum, HGV nonstructural region 5 (NS5) antigen (HGV Ag) in liver tissue and the amount of HBV DNA in serum, liver tissue were detected for 56 patients with CH-B by reverse transcription-polymerase chain reaction (RT-PCR) assay, peroxidase antiperoxidase (PAP) immunohistochemical method and fluorescence quantitative PCR assay, respectively. Then the relationship between HGV Ag expression in liver tissue and HGV RNA expression in serum was analysed and the amount of HBV DNA in serum and liver tissues from the serum HGV RNA or liver tissue HGV Ag positive patients were compared with those of the serum HGV-RNA or liver tissue HGV Ag negative patients, respectively.

<b>RESULTSb>Ten (17.9%) and eight (14.3%) patients were positive for serum and liver tissues,respectively.HGV RNA expression in serum was closely related to HGV Ag expression in liver tissues, but there was HGV RNA in serum from some of the liver tissues HGV Ag negative patients ?cases of HGV RNA and HGV Ag positive or negative,HGV RNA positive but HGV Ag negative, HGV RNA negative but HGV Ag positive, respectively: 5,43,5,3,(P<0.01). There was no significant difference in the amount of HBV DNA in serum and liver tissues between HGV RNA or HGV Ag positive and negative patients (P>0.05).

<b>CONCLUSIONSb>HGV infection may not affect HBV replication. Liver is the site of HGV replication, but HGV probably also replicates in extrahepatic tissues. HGV hepatic pathogenicity is probably mild and further studies are still needed.

Adult ; DNA, Viral ; analysis ; blood ; Female ; Flaviviridae Infections ; complications ; virology ; GB virus C ; genetics ; immunology ; pathogenicity ; Hepatitis Antigens ; analysis ; Hepatitis B virus ; genetics ; physiology ; Hepatitis B, Chronic ; complications ; virology ; Hepatitis, Viral, Human ; virology ; Humans ; Liver ; virology ; Male ; RNA, Viral ; blood ; Virus Replication

Hepatitis G virus (HGV) is a single-strand RNA virus in the Flaviviridae family, it was recently identified from the plasma of a patient with chronic hepatitis. HOV infection may cause acute and chronic liver disease by blood transfusion, drug addicts, hemophilia, and multiple sexual partners. But clinical significance of infectious pathway is still unclear. In this report, we amplified HGV RNA by reverse transcription-PCR (RT-PCR) by primers within the highly conserved 5'-noncoding region (NCR) and used restriction fragment length polymorphism (RFLP) method for the polymorphism analysis of amplified HGV gene. HGV was shown to be present in 7 of 78 (9.0%) from HCV RT-PCR positive serum samples and 5 of 58 (8.6%) from HCV RT-PCR negative serum samples. From the RFLP method HGV divided into four genotypes in 12 positive samples. Therefore, HGV genotype was distributed at least four different types in Korea.
Blood Transfusion ; Drug Users ; Flaviviridae ; GB virus C* ; Genotype ; Hemophilia A ; Hepatitis* ; Hepatitis, Chronic ; Humans ; Korea ; Liver Diseases ; Plasma ; Polymorphism, Restriction Fragment Length* ; RNA ; RNA Viruses ; Sexual Partners

Recently, two groups reported independently on the isolation of new positive-trand RNA viruses, designated hepatitis G virus (HGV) & GB virus C (GBV-C). Sequence analysis revealed that both genomes are different isolates of the same virus & represent a new genus of Flaviviridae. The prevalence of HGV ranges from 0.9 to 10% among blood donors throughout the world. A high prevalence of HGV RNA has been found in subjects with frequent parenteral exposure, including intravenous drug users, patients on hemodialysis, patients with hemophilia and patients with anemia. HGV is a blood borne virus that is parenterally transmitted. Vertical transmission has also been reported. HGV commonly occurs as a coinfection with another hepatitis virus such as HCV or HBV. However, HGV coinfection usually does not alter the clinical course or level of biochemical marker and the response to antiviral therapy of chronic hepatitis B or C in these patients. Acute HGV infection rarely causes acute hepatitis and is unlikely to be a major cause of chronic non-A-E hepatitis or fulminant viral hepatitis. HGV infection can be diagnosed by PCR assay to detect the viral RNA in serum. An enzyme-linked immunosorbent assay (ELISA) for detection of antibodies to recombinant HGV putative envelope protein E2 was recently available. But antibodies to E2 appears to be a serological marker for diagnosing recovery from HGV infection. Since the role of HGV as a etiologic agent of liver disease is unclear, therapy is not recommended at this point.
Anemia ; Antibodies ; Biomarkers ; Blood Donors ; Coinfection ; Diagnosis ; Drug Users ; Enzyme-Linked Immunosorbent Assay ; Flaviviridae ; GB virus C* ; Genome ; Hemophilia A ; Hepatitis B, Chronic ; Hepatitis Viruses ; Hepatitis* ; Humans ; Liver Diseases ; Polymerase Chain Reaction ; Prevalence ; Renal Dialysis ; RNA ; RNA Viruses ; RNA, Viral ; Sequence Analysis