Screening and identification of B cell epitopes of structural proteins of foot-and-mouth disease virus serotype Asia1

The objective of this study was to screen and identify the B cell epitopes of structural proteins of foot-and-mouth disease virus (FMDV) serotype Asia1. The complete amino acid sequence of all the four structural proteins (P1 region) was analyzed using the DNAStar Protean system. Seventeen peptides were predicted and selected as potential B cell epitopes. The potential B cell epitope genes were cloned into the pGEX-6P-1 plasmid, then expressed and purified. The resulting 17 glutathione S-transferase (GST) fusion peptides were detected by Western blot and ELISA for evaluation of their antigenicity. Six of the 17 fusion peptides were identified successfully by sera from rabbits immunized with the purified P1 polyprotein of FMDV type Asia1. The six fusion proteins were epi1-1 (VP1:₁TTTTGESADPVT₁₂), epi1-2 (VP1:₁₇NYGGETQTARRLH₂₉), epi1-6 (VP1:₁₉₄TTQDRRKQEIIAPEKQTL₂₁₁), epi2-2 (VP2:₄₀EDAVSGPNTSG₅₀), epi3-1 (VP3:₂₆YGKVSNPPRTSFPG₃₉), and epi4-2 (VP4:₃₀YQNSMDTQLGDN₄₁). The results of this study lay a foundation for further study of the structure and function of the structural proteins and may aid in the design of an epitope vaccine against foot-and-mouth disease (FMD) type Asia1. This study has also shown that the bioinformatics method, in combination with molecular biology methods can be used to map the B cell epitopes on viral proteins.