Optimization of Recombinant Glycoprotein D (gD) based Indirect ELISA for Detection of Antibodies against Bovine Herpesvirus-1

Bovine herpesvirus 1 (BoHV-1) affects mainly large ruminants (cattle and buffalo), resulting in a substantial negative impact on the industry. The virus causes respiratory symptoms, abortion and a decrease in milk production. Among envelope proteins of the virus, the glycoprotein D (gD) is considered a dominant immunogenic. We expressed the immunogenic portion of gD in the prokaryotic system (E. cloni 10G) and did evaluate its potential as a diagnostic antigen for indirect ELISA. Using the Ni-HRP probe, the expressed recombinant gD protein (rgD, 45kDa) was characterized by SDS-PAGE and western blotting. The immunogenic reactivity of red was optimized for indirect ELISA using known true positive and negative sera (antibodies) of the virus. Sera (n=158) were screened and, with a cut-off value of 0.238, relative diagnostic sensitivity (69%) and specificity (52.3%) of in-house developed indirect ELISA was determined. With these preliminary results, the study suggests the diagnostic potential of recombinant gD protein for serodiagnosis of BoHV-1 infection at a large scale.