AN ENZYME-LINKED-IMMUNOSORBENT-ASSAY TO DETECT ANTIBODIES AGAINST GLYCOPROTEIN GE OF BOVINE HERPESVIRUS-1 ALLOWS DIFFERENTIATION BETWEEN INFECTED AND VACCINATED CATTLE

A blocking enzyme-linked immunosorbent assay (ELISA) was developed for detecting antibodies against glycoprotein gE (gE) of bovine herpesvir us 1 (BHV1). The assay is based on the use of two monoclonal antibodie s directed against different antigenic domains on gE. Sera from uninfe cted cattle and cattle that had been repeatedly vaccinated with gE-neg ative marker vaccines scored negative, whereas sera from cattle natura lly or experimentally infected with BHV1 field strains scored positive in the gE-ELISA. Antibodies against gE appeared in the serum around 1 1 days after infection. Cattle that were first vaccinated and then cha llenged, thus having less virus replication, also became gE-seropositi ve. The sensitivity and specificity of the gE-ELISA is high, and there fore the gE-ELISA is suitable for differentiating between infected cat tle and vaccinated cattle with a gE-negative vaccine. (C) 1997 Elsevie r Science B.V.