title: Phenotypic and genotypic characteristics of novel mouse cell line (NIH/3T3)-adapted human enterovirus 71 strains (EV71:TLLm and EV71:TLLmv).
abstract: Since its identification in 1969, Enterovirus 71 (EV71) has been causing periodic outbreaks of infection in children worldwide and most prominently in the Asia-Pacific Region. Understanding the pathogenesis of Enterovirus 71 (EV71) is hampered by the virus's inability to infect small animals and replicate in their derived in vitro cultured cells. This manuscript describes the phenotypic and genotypic characteristics of two selected EV71 strains (EV71:TLLm and EV71:TLLmv), which have been adapted to replicate in mouse-derived NIH/3T3 cells, in contrast to the original parental virus which is only able to replicate in primate cell lines. The EV71:TLLm strain exhibited productive infection in all primate and rodent cell lines tested, while EV71:TLLmv exhibited greater preference for mouse cell lines. EV71:TLLmv displayed higher degree of adaptation and temperature adaptability in NIH/3T3 cells than in Vero cells, suggesting much higher fitness in NIH/3T3 cells. In comparison with the parental EV71:BS strain, the adapted strains accumulated multiple adaptive mutations in the genome resulting in amino acid substitutions, most notably in the capsid-encoding region (P1) and viral RNA-dependent RNA polymerase (3D). Two mutations, E167D and L169F, were mapped to the VP1 canyon that binds the SCARB2 receptor on host cells. Another two mutations, S135T and K140I, were located in the VP2 neutralization epitope spanning amino acids 136-150. This is the first report of human EV71 with the ability to productively infect rodent cell lines in vitro.
authors.affiliation: Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, Singapore; Host and Pathogen Interactivity Laboratory, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore.
authors.forename: Carla Bianca Luena
authors.initials: CB
authors.lastname: Victorio
authors.affiliation: Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, Singapore; Host and Pathogen Interactivity Laboratory, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore.
authors.forename: Yishi
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, Singapore.
authors.forename: Qimei
authors.initials: Q
authors.lastname: Ng
authors.affiliation: Host and Pathogen Interactivity Laboratory, Department of Microbiology, Yong Loo Lin School of Medicine, National University Health System, National University of Singapore, Singapore.
authors.forename: Vincent T K
authors.initials: VT
authors.lastname: Chow
authors.affiliation: Temasek Lifesciences Laboratory, 1 Research Link, National University of Singapore, Singapore.
authors.forename: Kaw Bing
authors.initials: KB
authors.lastname: Chua
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D000956:Antigens, Viral / Q000276:immunology; D003588:Cytopathogenic Effect, Viral; D029821:Enterovirus A, Human / Q000235:genetics* / Q000254:growth & development / Q000502:physiology*; D004769:Enterovirus Infections / Q000276:immunology / Q000821:virology; D016679:Genome, Viral; D005838:Genotype; D006801:Humans; D007700:Kinetics; D051379:Mice; D020125:Mutation, Missense / Q000235:genetics; D041681:NIH 3T3 Cells; D010641:Phenotype; D011323:Primates; D012367:RNA, Viral / Q000378:metabolism; D013696:Temperature; D014162:Transfection; D019562:Viral Load
chemical_list: D000956:Antigens, Viral; D012367:RNA, Viral