Baculovirus expression and diagnostic utility of the glycoprotein E of bovine herpesvirus-1.1 Egyptian strain "Abu-Hammad".

A recombinant baculovirus construct expressing glycoprotein E (gE) of the Egyptian BoHV-1.1 Abu-Hammad strain (rBac/gE-AbuH) was generated and characterized. The recombinant gE (rgE) secreting protein in culture medium of infected insect cells was used as a coating antigen in an indirect enzyme-linked immunosorbent assay (ELISA) to test its utility for detection of antibody against gE of BoHV-1. Indirect gE-ELISA was compared to standard virus neutralization test and commercial blocking gE-ELISA for detection of anti-gE antibody in a panel of bovine sera. Antibody titers estimated by both ELISAs were closely correlated with those determined by virus neutralization test. In conclusion, the developed indirect gE-ELISA was a reliable candidate for inexpensive detection of anti-gE antibody in control and experimental bovine sera with high specificity and sensitivity. Moreover, it emphasized the diagnostic utility of gE based ELISAs to distinguish cattle infected with BoHV-1 from those vaccinated with the gE negative mutants.