Functional divergence of the Bhanja virus NSs protein modulates interferon antagonism and viral fitness across divergent lineages.

Divergent NSs proteins in Bhanja virus enhance interferon antagonism and viral replication across lineages, with up to 2-fold increased suppression of interferon-beta induction.

• Why it matters: Understanding how viral proteins evade innate immunity is crucial for predicting virus behavior and developing interventions, especially for poorly characterized tick-borne viruses like BHAV.
• What they did: Using a reverse genetics system, 4 recombinant BHAV strains expressing NSs proteins from different geographic isolates were created and tested in mammalian cells, revealing functional differences in interferon suppression.
• The result: NSs variation modulates interferon antagonism and viral replication in vivo, providing insights into viral fitness and immune evasion, while maintaining an overall attenuated disease profile.