Identification and characterization of novel B-cell epitopes on the VP2 protein of bluetongue virus serotype 1.

Abstract

Bluetongue virus (BTV), a double-stranded RNA virus, comprises 36 serotypes and is one of the most widely distributed animal pathogens. VP2 is located on the outermost layer of BTV and contains the majority of epitopes that are recognized by neutralizing antibodies. To date, the B-cell epitopes on BTV-1 VP2 remain poorly characterized. In this study, the VP2was expressed in Escherichia coli and used to generate 10 monoclonal antibodies (mAbs) with hybridoma technology. Epitope mapping with truncated glutathione S-transferase fusion peptides identified two linear B-cell epitopes:TVTAQYT, recognized by mAbs 4A2, 4A8, 4D4, 4D5, 4E6, 4E8, and 4F3, andRLNHSTREITYAQG, recognized by mAbs 4B1, 4E3 and 4E1. A cross-reactivity analysis showed that these antibodies were specific to BTV-1 VP2. These findings identify two immunodominant epitopes on VP2 and provide a foundation for the development of epitope-based, BTV-specific diagnostics and subunit vaccines.