Udo Reischl and Christian Gerdes, Institute of Medical Microbiology and Hygiene, University of Regensburg, 93053 Regensburg, Germany
Serodiagnosis of Epstein-Barr virus (EBV) infection is currently based on the detection of antibodies to distinct EBV antigens. In the past few years the specificity and sensitivity of serodiagnostic assay systems have been considerably improved by the use of purified recombinant EBV antigens. After cloning and high-level expression of a particular viral protein as DHFR fusion protein in Escherichia coli, we purified the recombinant antigen to near homogeneity with the help of continuous elution electrophoresis. Sera from both EBVpositive and -negative donors were screened by immunoblot analysis and enzyme-linked immunosorbent assay for IgM and IgG antibodies against the EBV-encoded protein p23. The recombinant antigen seems to be a useful diagnostic marker for EBV infection, since antibodies were not detectable in 30 of 30 EBV-negative sera, and 294 of 302 EBV-positive sera contained either IgM or IgG anti-p23 antibodies (or both).
In the field of clinical diagnosis the determination of specific antibodies against distinct structural or functional antigenic proteins of a given pathogen is the most commonly used diagnostic tool for the detection of viral infections. Although most of the established test systems still use natural antigen from different sources, the advent of genetic engineering opens up the possibility of producing proteins of limited natural availability. Recombinant technology has already proven to be an excellent alternative for the production of specific antigens, which are