Related Experiment Video
Updated: Jul 4, 2026
Dissecting Innate Immune Signaling in Viral Evasion of Cytokine Production
Published on: March 2, 2014
The molecular basis of mouse adaptation by human enterovirus 71
Beng Hooi Chua1, Patchara Phuektes2,1, Sharon A Sanders1
1Division of Virology, Telethon Institute for Child Health Research, Perth, Australia.
Abstract:
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.
Insights
Researchers adapted human enterovirus 71 (HEV71) in cell culture and mice. A VP1 capsid mutation in the mouse-adapted strain (MP-26M) significantly increased HEV71 virulence in mice.
Area of Science:
- Virology
- Molecular Biology
- Pathogenesis
Background:
- Human enterovirus 71 (HEV71) is a significant human pathogen.
- Understanding HEV71 adaptation and virulence is crucial for developing effective countermeasures.
Purpose of the Study:
- To investigate the molecular basis of HEV71 adaptation to cell culture and mice.
- To identify specific viral mutations responsible for increased virulence in a mouse model.
Main Methods:
- Serial passage of a HEV71 clinical isolate in Chinese hamster ovary (CHO) cells and newborn BALB/c mice.
- Genetic sequencing to identify mutations in adapted viral strains.
- Generation and characterization of infectious cDNA clone-derived mutant viruses.
Main Results:
- HEV71 adapted to CHO cells (CHO-26M) showed improved cell growth but not increased mouse virulence.
- HEV71 adapted to mice (MP-26M) exhibited high mortality and severe necrotizing myositis.
- A single mutation in the VP1 capsid protein (G145E) of MP-26M was sufficient to confer high virulence in mice.
Conclusions:
- The VP2 (K149I) mutation enhances HEV71 growth in CHO cells but not mouse virulence.
- The VP1 (G145E) mutation is a key determinant of HEV71 virulence in newborn mice.
- This study elucidates specific viral genetic changes driving HEV71 pathogenesis and adaptation.
