Classical swine fever virus: Antigenic architecture of the E2 glycoprotein elucidated by epitope mapping using synthetic peptides

Detailed epitope characterization of the major envelope glycoprotein E2 of the classical swine fever virus (CSFV) is important for our understanding of interactions between the virus and the host immune system, as well as for the development of CSFV-specific diagnostic assays and epitope- or peptide-based marker vaccines. As was shown previously by competitive binding assay, monoclonal antibodies obtained by our group recognize eight epitopes on the E2 protein. Here, we report mapping of five linear, nonoverlapping B-cell epitopes that use a set of synthetic peptides, which encompass the full sequence of the CSFV E2 protein (Shimen strain). Two of the epitopes are located in the antigenic domain A of the E2, while another three belong to a highly structured region of this glycoprotein. The alignment of the identified gene sequences was performed for 12 CSFV strains, three strains of bovine viral diarrhea virus (BVDV), and two strains of the border disease virus (BDV). The data obtained could be used to improve CSFV diagnostic assays, as well as to investigate the effects of aminoacid substitutions in E2 on its antigenic properties.