Identification of a conserved linear epitope at the N terminus of the rabies virus glycoprotein

A novel, linear B-cell epitope has been identified at the N terminus of the rabies virus (RABV) glycoprotein. Screening of a phage-display library demonstrated that two glycoprotein-specific mAbs recognized a conserved sequence, WxxxDI, which aligned between aa 14 and 19 of the mature glycoprotein. Screening of truncated glycoprotein fragments with both mAbs confirmed the location of the epitope in the N-terminal region. Alignment of amino acid sequences from a range of RABV isolates indicated that the site was conserved in most viruses. Alignment with representatives of other lyssaviruses suggested that it is conserved within phylogroup I, which includes the European bat lyssaviruses, but not phylogroup II. A 12 aa synthetic peptide of this epitope was recognized by both mAbs and sera from a subset of rabies-vaccinated dogs. In a multimeric form, the peptide could induce an epitope-specific response following immunization in rabbits and mice.