Identification of Binding Sites for Neutralizing Monoclonal Antibodies on the 14-kDa Fusion Protein of Orthopox Viruses

A 14-kDa gene-specific probe of vaccinia virus Western Reserve (WR) hybridized to homologous sequences in the genomes of the orthopox virus species cowpox, camelpox, mousepox, and monkeypox virus. The corresponding genes were mapped and sequenced. Homologies of more than 95% were found when compared to the 14-kDa gene of vaccinia virus WR. However, point mutations which led to alterations in the amino acid sequences were mainly located between residues 26 and 40. By use of synthetic peptides, this part of the 14-kDa fusion protein could be identified as the binding site for four different neutralizing monoclonal antibodies.