The study published in the journal ACS Nano used cell-derived extracellular vesicles (EVs) as a vaccine platform to display various human and avian influenza hemagglutinins (HAs) in an upside-down manner on the EV surfaces. The inverted HA tends to present the conserved HA stalk to the immune system to induce cross-protective influenza immunity while hiding the highly variable HA head to avoid strain-specific immunity.

The investigators used mice to evaluate cellular and mucosal immune responses induced by the multiple HA EV vaccines. HA is a major influenza surface glycoprotein. EVs are natural nanoparticles that facilitate cell-to-cell communications.