Influenza A virus changes shape to evade immune responses

Influenza A virus changes shape to evade immune responses

Influenza A virus particles strategically adjust their shape to become spheres or larger filaments to favor their ability to infect cells depending on environmental conditions, according to a new study by the National Institutes of Health (NIH). This previously unrecognized response may help explain how influenza A and other viruses persist in populations, evade immune responses and acquire adaptive mutations, researchers explain in a new study published inNatural microbiology.

The study, led by intramural researchers at the NIH National Institute of Allergy and Infectious Diseases (NIAID), aimed to determine why many influenza A virus particles exist as filaments. The filament shape requires more energy to form than a sphere, they state, and its frequency has been previously unexplained. To find the answer, they developed a way to observe and measure real-time influenza virus structure as it forms.

The researchers found:

• Influenza -A -Viren passen ihre Form schnell an, wenn sie unter Bedingungen platziert werden, die die Infektionseffizienz verringern, z. B. das Vorhandensein antiviraler Antikörper oder die Inkompatibilität des Wirts.
• Die Form eines Virus ist dynamisch und wird von seiner Umgebung beeinflusst, anstatt wie allgemein angenommen durch Stamm fixiert zu werden.
• In der Studie wurden 16 verschiedene Virus-Zell-Kombinationen bewertet, die zu vorhersehbaren Formtrends führten.

The research team's previous experiments showed that influenza A virus filaments can resist inactivation by antibodies, and the team is working to understand exactly how antibodies influence shape and infection efficiency. They also expect to learn how viral mutations affect the shape of the virus. Many other viruses, such as measles, Ebola, Nipah, Hendra and respiratory syncytial virus, also contain a mixed-form infection strategy, the researchers note.

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