Application of equine infectious anemia virus core proteins produced in a baculovirus expression system to serological diagnosis.

Equine infectious anemia virus (EIAV) core proteins were obtained from a baculovirus expression system. Recombinant baculoviruses (rBVs) highly expressed the Gag precursor and p26 antigens in an rBV-infected Sf21 cell culture supernatant. Enzyme-linked immunosorbent assay (ELISA) and agar gel immunodiffusion (AGID) were conducted using the expressed proteins to detect antibodies from experimentally infected horses. The expressed antigens showed low background levels, high specificity and sensitivity in ELISA and AGID. The results of the serological tests using the expressed antigens were identical to those using a manufactured trial antigen. rBVs containing gag and p26 genes were found to express high quality and large quantities of Gag and p26 antigens, respectively. The antigens were quite useful for detecting anti-EIAV antibodies from virus-infected horses.