title: Immunochemical identification and partial characterization of a native hepatitis C viral non-structural 4 antigen in sera of HCV infected patients.
abstract: BACKGROUND
  The identification of native HCV antigens may prove very useful in the diagnosis and early treatment of HCV infection. Here, we aimed to identify and partially characterize a native HCV-NS4 antigen.
  
  
  METHODS
  The western blot, ELISA and immunohistochemical staining were used to identify the native antigen in sera and liver biopsies of HCV serotype 4 infected patients.
  
  
  RESULTS
  The native NS4 antigen was identified in serum at 27-kDa molecular weight, in addition to a lower approximately 21-kDa antigen. The purified HCV antigen showed a polypeptide band at 27-kDa when analyzed by silver stained SDS-PAGE and a single peak at 7.6 min by capillary zone electrophoresis. The immunostaining pattern of hepatocytes was cytoplasmic with mainly coarse granular and diffuse pattern based on specific rabbit antisera to the native HCV antigen. A highly significant correlation (r=0.797, p<0.0001) was shown between serum concentrations of the HCV-NS4 antigen and HCV-RNA. Also, antigen detection rates were increased (p<0.05) with the progression of liver disease.
  
  
  CONCLUSIONS
  A native HCV-NS4 antigen was identified and partially characterized as 27-kDa protein and the NS4 antigenemia based ELISA test can serve as a useful addition to HCV diagnostic methods, especially under field condition.
authors.affiliation: Research & Development Department, Biotechnology Research Center, New Damietta, Egypt. amattallah@hotmail.com
authors.forename: Abdelfattah M
authors.initials: AM
authors.lastname: Attallah
authors.forename: Hisham
authors.initials: H
authors.lastname: Ismail
authors.forename: Gamal E
authors.initials: GE
authors.lastname: Shiha
authors.forename: Mohamed I
authors.initials: MI
authors.lastname: Abou-Dobara
authors.forename: Rania E
authors.initials: RE
authors.lastname: El-Sherbiny
authors.forename: Ibrahim
authors.initials: I
authors.lastname: El-Dosoky
mesh_terms: D000293:Adolescent; D000328:Adult; D015153:Blotting, Western / Q000379:methods*; D002648:Child; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006526:Hepatitis C / Q000097:blood* / Q000276:immunology*; D018936:Hepatitis C Antigens / Q000097:blood* / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry; D008099:Liver / Q000276:immunology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D017361:Viral Nonstructural Proteins / Q000097:blood* / Q000276:immunology*
chemical_list: D018936:Hepatitis C Antigens; C093542:NS4 protein, hepatitis C virus; D017361:Viral Nonstructural Proteins