Screening and Identification of Linear B Cell Epitopes Within the Nonstructural Proteins of Enterovirus 71

Enterovirus 71 (EV-A71) has attracted widespread attention in the past decade because of its higher neurotropicity in addition to causing hand-foot-and-mouth disease (HFMD). Mapping epitopes of viral proteins may promote our understanding of antiviral humoral immunity, and is useful for clinical application. In this study, the linear B cell epitopes within nonstructural proteins of EV-A71 were identified using bioinformatics methods combined with peptide enzyme-linked immunosorbent assay (ELISA). Twenty epitopes were predicted and located at 2ABC (7), 3ABC (5), and 3D (8) protein, respectively. Of 20 epitope-containing peptides, 14 were verified by ELISA (S/CO >2.1), 9 of which had higher reactivity (S/CO >5.0). Furthermore, synthetic peptide SP09 (EV-A71-3ABC_26-41) can react with healthy children sera, and its immunoreactivity was closest to that of EV-A71-VP1 protein. The protein BLAST analysis revealed that SP09 may contain a common epitope due to the high homology of amino acid sequences with other members of human Enterovirus species A. These findings may be useful in the development serological tests for the diagnosis of HFMD caused by a broad range of human Enterovirus species A.