Detection of Aichi virus with antibody targeting of conserved viral protein 1 epitope

Aichi virus (AiV) is an emerging single-stranded, positive-sense, non-enveloped RNA virus in the Picornaviridae that causes acute gastroenteritis in humans. The first case of AiV infection in Taiwan was diagnosed in a human neonate with enterovirus-associated symptoms; the virus was successfully isolated and propagated. To establish a method to detect AiV, we analyzed the antigen epitope and generated a polyclonal antibody against AiV viral protein 1 (VP1). This peptide-purified anti-AiV VP1 antibody showed high specificity against AiV VP1 without cross-reaction to nine other tested strains of Picornaviruses. The anti-AiV VP1 antibody was used in immunofluorescence analysis, immunoblotting, and enzyme-linked immunosorbent assay to elucidate the cell tropism and replication kinetics of AiV. Use of the anti-AiV VP1 antibody also revealed AiV infection restriction with interferon type I and polyI/C antiviral treatment. The AiV infection and detection system may provide an in vitro platform for AiV virology study.