Antigenicity of Subregions of Recombinant Bovine Leukemia Virus (BLV) Glycoprotein Gp51 for Antibody Detection

Bovine leukemia virus (BLV) is an enveloped virus, found worldwide that can infect cattle and induce many subclinical symptoms and malignant tumors. BLV infection causes severe economic losses in the cattle industry. The identification of BLV-infected cattle for segregation or elimination would be the most effective way to halt the spread of BLV infection on farms, owing to the lack of effective treatments and vaccines. Therefore, antibody detection against the viral glycoprotein gp51 is an effective method for diagnosing BLV-infected animals. In this study, ten different subregions of gp51 containing a common B cell epitope are vital for developing antigens as epitope-driven vaccine design and immunological assays. Such antigens were produced in Escherichia coli expression system to react with antibodies in the serum from BLV-infected cattle and compete for antigenicity. Recombinant His-gp5156-110 and gp5133-301(full) had the same sensitivity in BLV-positive sera, indicating that antibodies responded to the limited subregion of viral gp51, a common B cell epitope. This finding provides significant information for antigen selection in BLV to use in antibody detection assays. Further studies are needed to evaluate the antigenicity of His-gp5156-110 and gp5133-301(full) as antigens for antibody detection assays using a larger number of bovine serum samples.