Researchers in the Institute for Biomedical Sciences at Georgia State University announced on Apr. 3 the development of a novel vaccine platform that provides broad protective immunity against various influenza virus infections.
This advancement is significant as it addresses the ongoing need for effective strategies to prevent influenza infection and transmission, especially during potential epidemics and pandemics. The study, published in ACS Nano, introduces a mucosal vaccine approach using cell-derived extracellular vesicles (EVs) to display different human and avian influenza hemagglutinins (HAs) in an upside-down orientation on their surfaces. This method exposes the conserved HA stalk to the immune system while concealing the highly variable HA head, aiming to promote cross-protective immunity rather than strain-specific responses.
In experiments involving mice, researchers found that immunization with these multiple HA-EV vaccines induced strong cellular and mucosal immune responses. EVs are natural nanoparticles known for facilitating cell-to-cell communication, while HA is a major surface glycoprotein of influenza viruses. The findings suggest that this EV-based inverted HA vaccine could be an important step toward developing universal flu vaccines delivered through mucosal routes.
Mucosal vaccination has been shown to induce local immune responses that protect against respiratory virus infections at their entry points. Despite various clinical trials investigating intranasal vaccines for respiratory viruses, FluMist remains the only FDA-approved mucosal influenza vaccine currently available. There is still an urgent need for new approaches that can trigger robust local immunity while ensuring safety.
"Intranasal immunization with multiple inverted HA-EV vaccines conferred complete protection against lethal heterosubtypic challenges with H7N9 and H5N1 reassortants," said Wandi Zhu, first author of the study and research assistant professor at Georgia State's Institute for Biomedical Sciences.
The study was supported by funding from the National Institute of Allergy and Infectious Diseases of the National Institutes of Health.
