GLYCOPROTEIN GE BLOCKING ELISAS TO DIFFERENTIATE BETWEEN AUJESZKYS-DISEASE-VACCINATED AND INFECTED ANIMALS

Three blocking ELISAs for the detection of antibodies against glycopro tein E (gE) of Aujeszky's disease virus (ADV) in sera (an indirect blo cking ELISA (gE-iELISA), a direct blocking ELISA (gE-dELISA) and a two -site 'sandwich' blocking ELISA (gE-sELISA)) have been developed. The gE-ELISAs are based on monoclonal antibodies (mAbs) directed to gE and detect gE-specific antibodies in sera by blocking the binding of mAbs to one (in the gE-iELISA. and the gE-dELISA) or two (in the gE-sELISA ) epitopes of gE. From a panel of thirteen gE-specific mAbs, mAbs, the ir conjugates and the combination coating mAb/conjugate that optimally detect anti-gE antibodies in the assays were selected. Sera from unin fected unvaccinated swine or swine vaccinated against different swine viral disorders were negative by three gE-ELISAs, the blocking gB-ELIS A, and VNT. Swine vaccinated with gE-negative vaccine were seropositiv e in the gB-ELISA and VNT but were seronegative by three gE-ELISAs. In fected unvaccinated swine, infected swine vaccinated with gE-negative vaccine, and swine vaccinated with gE-positive vaccine were detected a s seropositive by three gE-ELISAs as well as in the gB-ELISA; The gE-d ELISA and the gE-sELISA proved to be specific and the most sensitive a nd reliable assays to distinguish ADV-infected swine from those vaccin ated with gE-negative vaccine. These two gE-ELISAs were at least as se nsitive as the gB-ELISA for detecting ADV-specific antibodies. (C) 199 7 Elsevier Science B.V.