A highly specific and sensitive sandwich blocking ELISA based on baculovirus expressed pseudorabies virus glycoprotein B

A direct sandwich blocking enzyme-linked immunosorbent assay (BacgB ELISA) based on the reaction between a monoclonal antibody (MAb) and a recombinant glycoprotein B (gB) of pseudorabies virus (PRV) was developed. This protei n was obtained in large quantities from insect cells infected with a PRV gB recombinant baculovirus. Expression of the gB was confirmed by immunoperox idase monolayer assay (IPMA) with gB specific MAbs. The specificity and sen sitivity of the developed BacgB ELISA were evaluated and compared with two commercially available tests by using sets of sera of known PRV infection o r vaccination history. For validation, 347 serum samples have been tested. The BacgB ELISA had a high sensitivity and specificity, which were comparab le with those of the two commercial tests. In addition, the BacgB ELISA all ows detecting anti-gB antibodies in pig serum as early as 7 days following infection. Also maternal antibodies in uninfected pig sera were detected. W e conclude that the BacgB ELISA is a useful tool for the detection of as we ll vaccinated as infected pigs (including derivatives from gE negative vacc ine strains), with the added advantage that it uses an antigen that can be produced safely and in large quantities. (C) 2000 Elsevier Science B.V. All rights reserved.