Evaluation of antibodies to the Epstein-Barr virus immediate early gene product ZEBRA by a new enzyme-linked immunosorbent assay

For the serodiagnosis of Epstein-Barr virus (EBV) infections, we have devel oped a new enzyme-linked immunosorbent assay (ELISA) for antibodies to the ZEBRA product of EBV immediate early gene BZLF1, ZEBRA protein fused with g lutathione-S-transferase (GST) was expressed in Escherichia coli and purifi ed by affinity chromatography with glutathione-Sepharose 4B. An ELISA sandw ich capture system was constructed with the GST-ZEBRA immobilized on plasti c microtiter plates which had been coated with a mouse monoclonal antibody to GST. ZEBRA-IgC antibodies in patients' sera with chronic active EBV infe ction (CAEBV) and infectious mononucleosis (IM) had, respectively, very hig h and high titers. Anti-ZEBRA antibodies were also detected at low titers i n sera of some healthy controls. ZEBRA-IgM antibodies were detected in sera of patients with IM and CAEBV but not in sera of healthy controls. In sera of patients with CAEBV, the titers of IgG antibodies to ZEBRA correlated w ith the antibody titers to early antigens obtained with an immunofluorescen ce assay, but not to EBV nuclear antigens. This ELISA is a useful diagnosti c and prognostic test for EBV infection.