NIH

Influenza A viruses adapt shape in response to environmental pressures

February 24, 2025

Influenza A virus particles adapt their shape—becoming either spheres or filaments—based on environmental conditions, according to a new NIH study published in Nature Microbiology. This adaptive response helps explain how influenza A and other viruses persist, evade immune responses, and acquire mutations.

The study, led by researchers at NIH’s National Institute of Allergy and Infectious Diseases (NIAID), aimed to understand why many influenza A particles form filaments, which require more energy than spheres.

Key findings:

• Influenza A viruses rapidly change shape in response to conditions that reduce infection efficiency (e.g., antiviral antibodies, host incompatibility).
• Virus shape is dynamic and influenced by the environment, rather than being fixed by strain.
• From the 16 virus-cell combinations assessed, predictable shape trends were revealed.

Previous experiments showed that influenza A filaments resist antibody inactivation, and the team is now investigating how antibodies and viral mutations affect virus shape and infection efficiency.

Source:

(2025, February 10). NIH. Influenza A viruses adapt shape in response to environmental pressures [Media advisory]. https://www.nih.gov/news-events/news-releases/influenza-viruses-adapt-shape-response-environmental-pressures