Localization of the virus neutralizing and hemagglutinin epitopes of E1 glycoprotein of rubella virus

Current serological assays using whole rubella virus (RV) as a target antigen for detecting RV-specific antibodies fail to define specific RV proteins and antigenic determinants such as hemagglutinin (HA) and virus-neutralizing (VN) epitopes of rubella virus. A panel of El deletion mutants and a subset of E1-specific monoclonal antibodies (MAb) were used for the initial analysis of HA and VN epitopes of E1 glycoprotein. A peptide region (E1(193) to E1(269).) was found to contain HA and VN epitopes. Using both overlapping synthetic peptides and truncated fusion proteins within this region, the HA epitope defined by MAb 3D9F mapped to amino acid residues El(214) to El(240), while two VN epitopes defined by MAb 211391-1 and MAb 16A1 OE mapped to amino acid residues El (214) to E1(233) and E1(219) to E1(233), respectively. The epitopes defined in this study are recognized by antibody whether or not the epitopes are glycosylated.