Immunogenicity of transmembrane deleted-G protein of bovine ephemeral fever virus (BEFV) expressed in insect cells

Abstract

Bovine ephemeral fever (BEF) is a common febrile disease in cattle in tropical countries causing loss of milk production and reproductive performance. Recently, severe outbreaks have occurred in many countries in East Asia, the Middle East, and Southeast Asia, especially in the rainy season, while limited vaccines and diagnostic tools are available. Thus, the aim of this study was to produce a secreted, soluble form of BEFV G glycoprotein in insect cells for further applications. BEFV G gene expressing transmembrane-deleted G glycoprotein (G∆TM) was constructed and cloned into the baculovirus vector. The recombinant G∆TM protein was expressed in High5 insect cells and then purified by affinity chromatography. The purified G∆TM reacted specifically with a convalescent bovine serum. Four 8-week-old Wistar rats were injected subcutaneously with the purified G∆TM protein. Postimmunized rat serum samples also strongly reacted with the G protein by western blot and immunoperoxidase mono player assay (IPMA). These results indicated the potential use of the transmembrane-deleted G protein to develop protein based-diagnostic tools for BEFV control programs.