Discovery of a broad-spectrum monoclonal antibody recognizing a conserved, linear epitope WFYDGYPT on VP1 protein of Enterovirus A species.

Background: The hand, foot and mouth disease (HFMD) was caused by species of Enterovirus A and Enterovirus B in the Asian-Pacific region. Broad-spectrum monoclonal antibodies (mAb) that can bind multiple serotypes of enteroviruses have gradually become a research hotspot in the diagnosis, prevention and treatment of HFMD.

Methods: In this study, a mAb 1H4 was obtained using monoclonal antibody technology by immunizing purified virus particles of Coxsackievirus A5 (CV-A5). Examined by indirect immunofluorescence and Western blotting, 1H4 detected successfully all seven selected serotypes CV-A2, CV-A4, CV-A5, CV-A6, CV-A10, CV-A16 and EV-A71 of Enterovirus A and targeted structural protein VP1.

Results: The mAb 1H4 showed no cross-reactivity to strains of Enterovirus B and Enterovirus C. A linear epitope ₂₀₂WFYDGYPT₂₀₉ was identified as the minimal binding region of 1H4 by indirect ELISAs with overlapped and truncated peptides of VP1. Alanine scanning test found that W₂₀₂, F₂₀₃, D₂₀₅, G₂₀₆, Y₂₀₇, P₂₀₈, and T₂₀₉ were key residues in the epitope region. BLAST of the epitope in the NCBI genus Enterovirus protein database indicates that the epitope sequence is highly conserved among Enterovirus A species, but not among the other Enterovirus species.

Conclusions: The results suggest that the mAb 1H4 may be a useful tool for development with a cost-effective and accurate method for surveillance and early differentiation of serotypes from Enterovirus A species to other species.