Detection of flavivirus antibodies in human serum by epitope-blocking immunoassay.

Human flavivirus group-reactive, dengue complex-reactive, and encephalitis virus complex-reactive antibodies were detected using epitope-blocking immunoassays in which the binding of selected mouse monoclonal antibodies to flavivirus antigens was blocked by human serum. When late (greater than 6 months after illness) convalescent sera were tested, the epitope-blocking immunoassays were superior to the hemagglutination inhibition test and comparable to the plaque reduction neutralization for identifying subjects immune to dengue, to Japanese encephalitis, or both viruses.