Differentiation of serum antibodies from pigs vaccinated or infected with Aujeszky's disease virus by a competitive enzyme immunoassay.

A competitive enzyme immunoassay was developed to detect antibodies to a glycoprotein (gI) of Aujeszky's disease virus. Infected cell monolayers were used as antigen and a monoclonal antibody directed against an epitope of gI as indicator antibody. It was demonstrated that pigs vaccinated with the Bartha, BUK or NIA-4 strains did not produce antibody to the epitope of gI, whereas all wild-type viruses tested did induce this antibody. The antibody to the gI epitope persisted for at least 15 weeks. The present test, which enables us to distinguish pigs vaccinated with certain attenuated strains from pigs infected with wild-type Aujeszky's disease virus, may be of great value in future combined vaccination-eradication programmes for Aujeszky's disease.