The molecular basis of mouse adaptation by human enterovirus 71.
A mouse-adapted strain of human enterovirus 71 (HEV71) was selected by serial passage of a HEV71 clinical isolate (HEV71-26M) in Chinese hamster ovary (CHO) cells (CHO-26M) and in newborn BALB/c mice (MP-26M). Despite improved growth in CHO cells, CHO-26M did not show increased virulence in newborn BALB/c mice compared with HEV71-26M. By contrast, infection of newborn mice with MP-26M resulted in severe disease of high mortality. Skeletal muscle was the primary site of replication in mice for both viruses. However, MP-26M infection induced severe necrotizing myositis, whereas CHO-26M infection caused only mild inflammation. MP-26M was also isolated from whole blood, heart, liver, spleen and brain of infected mice. CHO-26M harboured a single mutation within the open reading frame (ORF), resulting in an amino acid substitution of K(149)-->I in the VP2 capsid protein; two further ORF mutations that resulted in amino acid substitutions were identified in MP-26M, located within the VP1 capsid protein (G(145)-->E) and the 2C protein (K(216)-->R). Infectious cDNA clone-derived mutant virus populations containing the mutations identified in CHO-26M and MP-26M were generated in order to study the molecular basis of CHO cell and mouse adaptation. The VP2 (K(149)-->I) change was responsible only for improved growth in CHO cells and did not lead to increased virulence in mice. Of the two amino acid substitutions identified in MP-26M, the VP1 (G(145)-->E) mutation alone was sufficient to increase virulence in mice to the level observed in MP-26M-infected mice.
Chua
Beng Hooi
BH
Division of Virology, Telethon Institute for Child Health Research, Perth, Australia.
Phuektes
Patchara
P
School of Veterinary and Biomedical Sciences, Murdoch University, Perth, Australia.|Division of Virology, Telethon Institute for Child Health Research, Perth, Australia.
Sanders
Sharon A
SA
Division of Virology, Telethon Institute for Child Health Research, Perth, Australia.
Nicholls
Philip K
PK
School of Veterinary and Biomedical Sciences, Murdoch University, Perth, Australia.
McMinn
Peter C
PC
Discipline of Infectious Diseases and Immunology, The University of Sydney, Australia.|Division of Virology, Telethon Institute for Child Health Research, Perth, Australia.
D000220:Adaptation, Biological; D019943:Amino Acid Substitution / Q000235:genetics; D000818:Animals; D000831:Animals, Newborn; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004252:DNA Mutational Analysis; D029821:Enterovirus A, Human / Q000235:genetics* / Q000254:growth & development / Q000472:pathogenicity*; D004769:Enterovirus Infections / Q000821:virology; D054884:Host-Pathogen Interactions; D006801:Humans; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D018482:Muscle, Skeletal / Q000473:pathology / Q000821:virology; D020125:Mutation, Missense; D009220:Myositis / Q000821:virology; D009336:Necrosis; D017422:Sequence Analysis, DNA; D012692:Serial Passage; D016019:Survival Analysis; D015678:Viral Structural Proteins / Q000235:genetics; D014774:Virulence
D015678:Viral Structural Proteins