Torque teno virus(TTV) has been found to be prevalent world-wide in healthy populations and in patients with various diseases, but its etiological role has not yet been determined. Using high-throughput unbiased seque...Torque teno virus(TTV) has been found to be prevalent world-wide in healthy populations and in patients with various diseases, but its etiological role has not yet been determined. Using high-throughput unbiased sequencing to screen for viruses in the serum of a patient with persistent high fever who died of suspected viral infection and prolonged weakness, we identified the complete genome sequence of a TTV(isolate Hebei-1). The genome of TTV-Hebei-1 is 3649 bp in length, encoding four putative open reading frames, and it has a G+C content of 49%. Genomic comparison and a BLASTN search revealed that the assembled genome of TTV-Hebei-1 represented a novel isolate, with a genome sequence that was highly heterologous to the sequences of other reported TTV strains. A phylogenetic tree constructed using the complete genome sequence showed that TTV-Hebei-1 and an uncharacterized Taiwan Residents strain, TW53A37, constitute a new TTV genotype. The patient was strongly suspected of carrying a viral infection and died eventually without any other possible causes being apparent. No virus other than the novel TTV was identified in his serum sample. Although a direct causal link between the novel TTV genotype infection and the patient's disease could not be confirmed, the findings suggest that surveillance of this novel TTV genotype is necessary and that its role in disease deserves to be explored.展开更多
Several receptors have been identified as implicated on viral entry into the hepatocyte; and, this interaction between the virus and potential receptors could modulate infection, spontaneous viral clearance, persisten...Several receptors have been identified as implicated on viral entry into the hepatocyte; and, this interaction between the virus and potential receptors could modulate infection, spontaneous viral clearance, persistence of the infection and the widespread of the virus as outbreak. Nevertheless, the playing role of each of them remains controversial. The NiemannPick type C1 like 1 gene (NPC1L1) receptor has been recently implicated on hepatitis C virus (HCV) entry into the cell and ezetimibe, an anti-cholesterol drug seems to block that, emerging the idea to control hepatitis C outbreak modulating lipid-related receptors. Hepatitis C infection seems to modulate lipid metabolism according to host genetic background. Indeed, it circulates like a lipoviroparticle. The main aim of this field of vision would be to discuss the role of hepatocyte receptors implicated on virus entry, especially NPC1L1 and the therapeutic options derived from the better knowledge about HCV-lipidsreceptors interaction.展开更多
Many flaviviruses are emerging and reemerging pathogens, such as West Nile virus （WNV）, dengue virus （DENV）, yellow fever virus （YFV）, and Japanese encephalitis virus. Serological assay is the dominant method fo...Many flaviviruses are emerging and reemerging pathogens, such as West Nile virus （WNV）, dengue virus （DENV）, yellow fever virus （YFV）, and Japanese encephalitis virus. Serological assay is the dominant method for diagnosis of flavivirus infections in human. Because antibodies generated during flavivirus infections cross-react with other flavivirus members, plaque reduction neutralization test （PRNT） is the only available assay to determine the infecting flavivirus type. Since PRNT requires culturing raw viruses, it must be performed in biosafety levet-3 or level-4 containment for many flaviviruses, and takes more than ten days to complete. To overcome these problems, we have developed flavivirus viral-like particles （VLPs） that could be used to replace raw viruses in the neutralization assay. The VLPs were prepared by trans packaging a luciferase-reporting replicon with viral structural proteins. This novel assay involves three simple steps： （i） VLPs from a panel of flaviviruses are incubated with flavivirus-infected sera at 37℃ for 1 h; （ii）the neutralized VLPs are used to infect Vero cells; and （iii） the infected cells are measured for luciferase activities at 22 h post-infection. The virus type whose VLP is most efficiently neutralized by the serum specimen （as quantified by the luciferase activities） is the etiologic agent. As a proof-of-concept, we show that a WNV-infected mouse serum neutralized the WNV VLP more efficiently and selectively than the DENV and YFV VLPs. Our results demonstrate that the VLP neutralization assay maintains the ＂gold standard＂ of the classic PRNT; importantly, it shortens the assay time from 〉10 days to 〈1 day, and can be performed in biosafety level-2 facility.展开更多
The nucleocapsid protein(N) is a major structural protein of coronaviruses. The N protein of bat SARS-like coronavirus(SL-CoV) has a high similarity with that of SARS-CoV. In this study,the SL-CoV N protein was expres...The nucleocapsid protein(N) is a major structural protein of coronaviruses. The N protein of bat SARS-like coronavirus(SL-CoV) has a high similarity with that of SARS-CoV. In this study,the SL-CoV N protein was expressed in Escherichia coli,purified and used as antigen. An Indirect Enzyme-Linked Immunosorbent Assay(indirect ELISA) was developed for detection of SARS-or SL-CoV infections in bat populations. The detection of 573 bat sera with this indirect ELISA demonstrated that SL-CoVs consistently circulate in Rhinilophus species,further supporting the proposal that bats are natural reservoirs of SL-CoVs. This method uses 1-2 μl of serum sample and can be used for preliminary screening of infections by SARS-or SL-CoV with a small amount of serum sample.展开更多
AIM:To investigate the current seroprevalence of hepatitis A virus(HAV) antibodies in patients with chronic viral liver disease in Korea.We also tried to identify the factors affecting the prevalence of HAV antibodies...AIM:To investigate the current seroprevalence of hepatitis A virus(HAV) antibodies in patients with chronic viral liver disease in Korea.We also tried to identify the factors affecting the prevalence of HAV antibodies. METHODS:We performed an analysis of the clinical records of 986 patients(mean age:49±9 years,714 males/272 females) with chronic hepatitis B virus(HBV) or hepatitis C virus(HCV) infection who had undergone HAV antibody testing between January 2008 and December 2009.RESULTS:The overall prevalence of IgG anti-HAV was 86.61%(854/986) in patients with chronic liver disease and was 88.13%(869/986) in age-and gendermatched patients from the Center for Health Promotion.The anti-HAV prevalence was 80.04%(405/506) in patients with chronic hepatitis B,86.96%(20/23) in patients with chronic hepatitis C,93.78%(422/450) in patients with HBV related liver cirrhosis,and 100%(7/7) in patients with HCV related liver cirrhosis.The anti-HAV prevalence according to the decade of age was as follows:20s(6.67%) ,30s(50.86%) ,40s(92.29%) ,50s(97.77%) ,and 60s(100%) .The antiHAV prevalence was significantly higher in patients older than 40 years compared with that in patients younger than 40 years of age.Multivariable analysis showed that age≥40 years,female gender and metropolitan cities as the place of residence were independent risk factors for IgG anti-HAV seropositivity. CONCLUSION:Most Korean patients with chronic liver disease and who are above 40 years of age have already been exposed to hepatitis A virus.展开更多
基金supported by a grant from the National Natural Science Foundation of China (No. 81072350)the National Hi-Tech Research and Development (863) Program of China (No. 2012AA022-003)+2 种基金the China Mega-Project on Major Drug Development (No. 2011ZX09401-023)the China Mega-Project on Infectious Disease Prevention (No. 2013ZX10004-605, No. 2013ZX10004-607, No. 2013ZX10004-217, and No. 2011ZX10004-001) the State Key Laboratory of Pathogen and BioSecurity Program (No. SKLPBS1113)
文摘Torque teno virus(TTV) has been found to be prevalent world-wide in healthy populations and in patients with various diseases, but its etiological role has not yet been determined. Using high-throughput unbiased sequencing to screen for viruses in the serum of a patient with persistent high fever who died of suspected viral infection and prolonged weakness, we identified the complete genome sequence of a TTV(isolate Hebei-1). The genome of TTV-Hebei-1 is 3649 bp in length, encoding four putative open reading frames, and it has a G+C content of 49%. Genomic comparison and a BLASTN search revealed that the assembled genome of TTV-Hebei-1 represented a novel isolate, with a genome sequence that was highly heterologous to the sequences of other reported TTV strains. A phylogenetic tree constructed using the complete genome sequence showed that TTV-Hebei-1 and an uncharacterized Taiwan Residents strain, TW53A37, constitute a new TTV genotype. The patient was strongly suspected of carrying a viral infection and died eventually without any other possible causes being apparent. No virus other than the novel TTV was identified in his serum sample. Although a direct causal link between the novel TTV genotype infection and the patient's disease could not be confirmed, the findings suggest that surveillance of this novel TTV genotype is necessary and that its role in disease deserves to be explored.
文摘Several receptors have been identified as implicated on viral entry into the hepatocyte; and, this interaction between the virus and potential receptors could modulate infection, spontaneous viral clearance, persistence of the infection and the widespread of the virus as outbreak. Nevertheless, the playing role of each of them remains controversial. The NiemannPick type C1 like 1 gene (NPC1L1) receptor has been recently implicated on hepatitis C virus (HCV) entry into the cell and ezetimibe, an anti-cholesterol drug seems to block that, emerging the idea to control hepatitis C outbreak modulating lipid-related receptors. Hepatitis C infection seems to modulate lipid metabolism according to host genetic background. Indeed, it circulates like a lipoviroparticle. The main aim of this field of vision would be to discuss the role of hepatocyte receptors implicated on virus entry, especially NPC1L1 and the therapeutic options derived from the better knowledge about HCV-lipidsreceptors interaction.
基金supported by National Institute of Health grants U01 AI061193 and U54-AI057158 (Northeast Biodefense Center).
文摘Many flaviviruses are emerging and reemerging pathogens, such as West Nile virus （WNV）, dengue virus （DENV）, yellow fever virus （YFV）, and Japanese encephalitis virus. Serological assay is the dominant method for diagnosis of flavivirus infections in human. Because antibodies generated during flavivirus infections cross-react with other flavivirus members, plaque reduction neutralization test （PRNT） is the only available assay to determine the infecting flavivirus type. Since PRNT requires culturing raw viruses, it must be performed in biosafety levet-3 or level-4 containment for many flaviviruses, and takes more than ten days to complete. To overcome these problems, we have developed flavivirus viral-like particles （VLPs） that could be used to replace raw viruses in the neutralization assay. The VLPs were prepared by trans packaging a luciferase-reporting replicon with viral structural proteins. This novel assay involves three simple steps： （i） VLPs from a panel of flaviviruses are incubated with flavivirus-infected sera at 37℃ for 1 h; （ii）the neutralized VLPs are used to infect Vero cells; and （iii） the infected cells are measured for luciferase activities at 22 h post-infection. The virus type whose VLP is most efficiently neutralized by the serum specimen （as quantified by the luciferase activities） is the etiologic agent. As a proof-of-concept, we show that a WNV-infected mouse serum neutralized the WNV VLP more efficiently and selectively than the DENV and YFV VLPs. Our results demonstrate that the VLP neutralization assay maintains the ＂gold standard＂ of the classic PRNT; importantly, it shortens the assay time from 〉10 days to 〈1 day, and can be performed in biosafety level-2 facility.
基金The State Key Program for Basic Research Grant (2005CB523004) The Knowledge InnovationProgram Key Project (KSCX1-YW-R-07).
文摘The nucleocapsid protein(N) is a major structural protein of coronaviruses. The N protein of bat SARS-like coronavirus(SL-CoV) has a high similarity with that of SARS-CoV. In this study,the SL-CoV N protein was expressed in Escherichia coli,purified and used as antigen. An Indirect Enzyme-Linked Immunosorbent Assay(indirect ELISA) was developed for detection of SARS-or SL-CoV infections in bat populations. The detection of 573 bat sera with this indirect ELISA demonstrated that SL-CoVs consistently circulate in Rhinilophus species,further supporting the proposal that bats are natural reservoirs of SL-CoVs. This method uses 1-2 μl of serum sample and can be used for preliminary screening of infections by SARS-or SL-CoV with a small amount of serum sample.
文摘AIM:To investigate the current seroprevalence of hepatitis A virus(HAV) antibodies in patients with chronic viral liver disease in Korea.We also tried to identify the factors affecting the prevalence of HAV antibodies. METHODS:We performed an analysis of the clinical records of 986 patients(mean age:49±9 years,714 males/272 females) with chronic hepatitis B virus(HBV) or hepatitis C virus(HCV) infection who had undergone HAV antibody testing between January 2008 and December 2009.RESULTS:The overall prevalence of IgG anti-HAV was 86.61%(854/986) in patients with chronic liver disease and was 88.13%(869/986) in age-and gendermatched patients from the Center for Health Promotion.The anti-HAV prevalence was 80.04%(405/506) in patients with chronic hepatitis B,86.96%(20/23) in patients with chronic hepatitis C,93.78%(422/450) in patients with HBV related liver cirrhosis,and 100%(7/7) in patients with HCV related liver cirrhosis.The anti-HAV prevalence according to the decade of age was as follows:20s(6.67%) ,30s(50.86%) ,40s(92.29%) ,50s(97.77%) ,and 60s(100%) .The antiHAV prevalence was significantly higher in patients older than 40 years compared with that in patients younger than 40 years of age.Multivariable analysis showed that age≥40 years,female gender and metropolitan cities as the place of residence were independent risk factors for IgG anti-HAV seropositivity. CONCLUSION:Most Korean patients with chronic liver disease and who are above 40 years of age have already been exposed to hepatitis A virus.
