title: Use of recombinant Epstein-Barr virus early antigen for detection of antibody in patients with nasopharyngeal carcinoma.
abstract: BACKGROUND
  Nasopharyngeal carcinoma (NPC) is one of the most common cancers in southern China and Taiwan. Serological studies revealed the close-relationship between NPC and Epstein-Barr virus (EBV). Elevated serum and saliva levels of anti-EBV antibodies are detected in patients with NPC. Therefore, Development Center for Biotechnology prepared the EBV-early antigen (EA-D) by recombinant DNA technique for screening the serum and throat washing samples from patients with head and neck cancers.
  
  
  METHODS
  The BMRF1 gene for EBV early antigen (EA-D) was placed into the plasmid pDB18, then transformed into an Escherichia coli strain containing the lambda cI857 temperature-sensitive repressor. Heat treatment of the transformant, at exponential growth phase, inactivated the cI protein and induced an over-expression of the EA-D protein. Next, the EA-D was purified by chromatography and characterized as a protein of molecular weight 47 kDa, by sodium dodecyl sulfate-polyacry lamide gel electrophoresis (SDS-PAGE) and Western blot analysis using monoclonal anti-EA antibody and sera from patients with nasopharyngeal carcinoma (NPC). Enzyme-linked immunosorbent assay (ELISA) with the purified EA-D antigen was used to screen 129 serum and throat washing (TW) samples from patients with head and neck tumors, 24 from patients with a nonmalignant disease and 44 from normal donors.
  
  
  RESULTS
  Experimental results indicated significantly higher positive rates of EA-D IgA (69%) and EA-D IgG (91%) in NPC sera than in the sera of patients with other head and neck tumors and normal controls. TW samples from patients with NPC also showed a higher positive rate (34%) than the other groups (7-20%).
  
  
  CONCLUSIONS
  Results in this study demonstrate that the bacterially expressed EA-D antigen could be recognized by sera from patients with NPC and monoclonal anti-EA antibody. Thus, it has potential use in ELISA for screening EBV-related diseases such as NPC.
authors.affiliation: Department of Medical Research, Taichung Veterans General Hospital, Taipei, Taiwan, R.O.C.
authors.forename: M T
authors.initials: MT
authors.lastname: Liu
authors.forename: L S
authors.initials: LS
authors.lastname: Lin
authors.forename: Y
authors.initials: Y
authors.lastname: Yu
authors.forename: T T
authors.initials: TT
authors.lastname: Chung
authors.forename: C Y
authors.initials: CY
authors.lastname: Hsu
authors.forename: J T
authors.initials: JT
authors.lastname: Chen
authors.forename: K C
authors.initials: KC
authors.lastname: Jeng
mesh_terms: D000914:Antibodies, Viral / Q000032:analysis*; D000956:Antigens, Viral / Q000276:immunology*; D001483:Base Sequence; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D004854:Herpesvirus 4, Human / Q000276:immunology*; D006801:Humans; D008969:Molecular Sequence Data; D009303:Nasopharyngeal Neoplasms / Q000821:virology*; D011994:Recombinant Proteins / Q000276:immunology
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; C033305:Epstein-Barr virus early antigen; D011994:Recombinant Proteins