Differentiation of two bovine lentiviruses by a monoclonal antibody on thebasis of epitope specificity

Bovine immunodeficiency virus (BIV) and Jembrana disease virus (JDV) are bo vine lentiviruses that are closely related genetically. A recombinant fusio n protein containing the capsid protein of BIV expressed in Escherichia coi l was used to immunize mice and produce monoclonal antibodies. Six hybridom as specific for BTV capsid protein were identified, and one antibody, desig nated 10H1, was characterized further. Competitive binding assays were perf ormed to analyze the topography of antigenic determinants by enzyme-linked immunosorbent assay and demonstrated the existence of at least three distin ct antigenic determinants on capsid protein. The monoclonal antibody reacte d specifically with both BIV capsid and the recombinant fusion protein in W estern immunoblot analyses. However, it did not react with the recombinant capsid fusion protein of JDV, indicating that BIV contains at least one uni que epitope in the capsid protein that is absent in JDV, Further mapping of the epitope by chemical cleavage analysis identified that the epitope is l ocated at the 6.4-kDa N terminus of the 29-kDa capsid protein. This monoclo nal antibody assay will be valuable for distinguishing the two closely rela ted lentiviruses by Western blotting.