Use of bacterial trpE fusion vectors to express and characterize the bovine immunodeficiency-like virus core protein

The gag coding region from Bovine Immunodeficiency-like Virus (BIV) was cloned into E. coli and expressed as a bacterial fusion protein. Six different clones spanning various regions of the gag open reading frame were generated. The resulting fusion proteins were expressed at high concentrations and readily purified. A panel of bovine immune sera specifically recognized the recombinant Gag proteins, as did immune sera from animals infected or immunized with lentiviruses related to BIV, such as Equine Infectious Anemia Virus (EIAV) and Human Immunodeficiency Virus (HIV). Analysis of the deletion clones, using the bovine immune sera panel, enabled us to identify at least one major epitope which was specifically recognized by all bovine sera examined. The ease of expression, purification, and specificity of these fusion proteins should enable a thorough study of the epidemiology of BIV infection.