Abstract

VP2 is a structural protein of the foot-and-mouth disease virus (FMDV). In this study, a FMDV serotype-independent monoclonal antibody (MAb), 4B2, was generated. By screening a phage-displayed random 12-peptide library, we found positive phages displaying the consensus motif ETTXLE (X is any amino acid (aa)), which is highly homologous to 6ETTLLE11 at the N-terminus of the VP2 protein. Subsequently, a series of GST-fusion proteins expressing a truncated N-terminus of VP2 were examined by western blot analysis using the MAb 4B2. The results indicated that the motif 6ETTLLE11 of VP2 may be the minimal requirement of the epitope recognized by 4B2. Moreover, a 12-aa peptide 2KKTEETTLLEDR13 was shown to be the minimal unit of the epitope with maximal binding activity to 4B2. Alanine-scanning analysis demonstrated thatThr7, Thr8, and Leu10 are the functional residues of the 4B2 epitope Glu6 and Leu9 are required residues, and Glu11 plays a crucial role in the binding of MAb 4B2. The fine mapping of the epitope indicated that MAb 4B2 has the potential to be used in FMDV diagnosis.

• Keywords: foot-and-mouth disease virus; monoclonal antibody; phage display; VP2; epitope mapping