Experimental Infection Using Mouse-Adapted Influenza B Virus in a Mouse Model

Area of Science:

• Virology
• Immunology
• Pathology

Background:

• Influenza B viruses (IBVs) cause significant human illness and respiratory disease.
• Developing effective vaccines and antiviral drugs requires robust preclinical models.
• Current mouse models may not fully represent human influenza B infections.

Purpose of the Study:

• To develop and characterize a mouse model for influenza B virus infection.
• To evaluate the efficacy of antiviral drugs and vaccines using this model.
• To facilitate preclinical testing of influenza B therapeutics.

Main Methods:

• Serial passage of a Victoria lineage IBV (clade 1A) in BALB/c mice.
• Adaptation analysis of hemagglutinin (HA) and neuraminidase (NA) genes.
• Pathogenicity assessment via viral load, histopathology, and clinical signs.
• In vitro and in vivo efficacy testing of oseltamivir and Ultrix® vaccine.

Main Results:

• Mouse-adapted IBV exhibited characteristic influenza pneumonia.
• Adaptive mutations (T214I in HA, D432N in NA) were identified.
• Oseltamivir and the Ultrix® vaccine demonstrated significant efficacy against the adapted IBV.

Conclusions:

• A mouse-adapted IBV model was successfully developed.
• This model is suitable for evaluating anti-influenza B drug and vaccine efficacy.
• The developed model supports preclinical assessment of novel influenza B interventions.