N1 neuraminidase monoclonal antibodies 2H08 and 3H03 have decreased binding and inhibition properties against H1N1 influenza viruses circulating after 2018

Two broadly protective N1 neuraminidase monoclonal antibodies, 2H08 and 3H03, show decreased binding and inhibition against seasonal H1N1 N1s circulating after 2018.

• Why it matters: Antigenic evolution of neuraminidase is understudied, even as vaccines require annual updates due to hemagglutinin drift.
• What they did: The study tested binding and inhibition of 2H08 and 3H03 against recent seasonal H1N1 N1 neuraminidase, linking reduced activity to a shift in electrostatic surface potential from neutral to positively charged.
• The result: The activity drop was not seen with historic human plasma samples, suggesting it is specific to these two mAbs, while both mAbs remained fully active against pan-zootic clade 2.3.4.4b H5N1 neuraminidase.