LOCALIZATION AND DIAGNOSTIC APPLICATION OF IMMUNODOMINANT DOMAINS OF THE BFRF3-ENCODED EPSTEIN-BARR-VIRUS CAPSID PROTEIN

The Epstein-Barr virus (EBV) open reading frame BFRF3 encodes a viral structural capsid protein or tegument protein, VCA p18, that is highly immunogenic in humans. In this study, a cluster of immunodominant epi topes in the C-terminus of VCA p18 has been identified. These epitopes were combined into a single synthetic peptide that was analyzed for d iagnostic value in an ELISA. This VCA combined peptide appeared to be an excellent VCA marker with remarkable applications for IgG- and IgM- related EBV diagnostics. The combined peptide reacted with 95% of 159 sera that were IgG VCA-positive by immunofluorescence assay. In additi on, 95% of sera from 67 persons with confirmed infectious mononucleosi s were positive for IgM antibodies to this VCA combined peptide. An Ig G-specific seroconversion could be demonstrated by subsequent serum sa mples during the acute phase of primary EBV infections. Although 97% o f the tested sera from nasopharyngeal carcinoma patients had IgG antib odies reacting positively with the VCA combined peptide, only 61% cont ained IgA anti-VCA combined peptide.