Dear Editor,
Previous studies had described the adaptation of enterovirus 71 (EV-A71) strains that enabled entry and viral replication in Chinese Hamster Ovary (CHO) cell line (Zaini and McMinn 2012;Zaini et al.2012).These adapted strains derived from serial passage of a clinical isolate in CHO cells exhibited an amino acid substitution at VP2149,which enhanced viral replication by 100~1000-fold compared to the clinical isolate.The VP2149 mutation was claimed responsible for adaptation to CHO-K1 cells without performing detailed molecular analyses to support these claims.In this study,we evaluate various VP1 and VP2 mutations in two CHO-adapted EV-A71 strains derived in our lab to assess their contribution to the phenotype of CHO cell adaptation.