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 developed a new enzyme-linked immunosorbent assay (ELISA) for antibodies to the ZEBRA product of EBV immediate early gene BZLF1. ZEBRA protein fused with glutathione-S-transferase (GST) was expressed in Escherichia coli and purified by affinity chromatography with glutathione-Sepharose 4B. An ELISA sandwich capture system was constructed with the GST-ZEBRA immobilized on plastic microtiter plates which had been coated with a mouse monoclonal antibody to GST. ZEBRA-IgG antibodies in patients' sera with chronic active EBV infection (CAEBV) and infectious mononucleosis (IM) had, respectively, very high and high titers. Anti-ZEBRA antibodies were also detected at low titers in 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 with the antibody titers to early antigens obtained with an immunofluorescence assay, but not to EBV nuclear antigens. This ELISA is a useful diagnostic and prognostic test for EBV infection.