Collaborators produce a universal flu vaccine candidate

Australian and Singaporean scientists have proved that a single-shot immunisation containing the M2e peptide is able to trigger long-lasting immune responses that could protect effectively against multiple strains of influenza. Their results have been published in the journal Proceedings of the National Academy of Sciences.

Although vaccination arguably represents the most effective way to prevent influenza, current vaccination strategies suffer from certain limitations, chief of which require current influenza vaccines to be updated annually to match circulating strains. This results in low vaccination take-up rates and poor coverage due to inaccurate prediction of circulating strains. Broadly protective, ‘universal’ flu vaccines that do not need to be updated annually have therefore been pursued.

The highly conserved M2e peptide is a leading universal flu candidate; this peptide shares a conserved sequence with nearly all known human Influenza A strains. However, its limited ability to trigger a strong and long-lasting immune response has represented a major roadblock in its clinical development. Researchers from the National University of Singapore and Monash University have now leveraged a novel vaccine platform to deliver M2e to immune cells.

This vaccine approach has the potential to minimise the amount of M2e vaccine antigen (substance that triggers the body’s immune response against that itself) and the number of injections required for effective and long-lasting protection. It also removes the need for strong adjuvants (a substance which enhances the body’s immune response to an antigen), reducing potential side effects — particularly in more vulnerable populations.

The team was also able to demonstrate that this vaccination approach significantly enhanced protective immune responses in the context of pre-existing flu immunity. This scenario is particularly relevant in adult and elderly populations, where individuals have been exposed to flu viruses multiple times in the past and have low levels of M2e-specific antibodies in their blood circulation.

Beyond the flu, the vaccine platform could be employed to tackle a multitude of diseases. The research team is currently working on a COVID-19 vaccine candidate using the same strategy.

“In the world we live in, this vaccine platform provides a key opportunity for developing vaccines and immunotherapies to meet future global health threats,” said Associate Professor Mireille Lahoud, who leads the Dendritic Cell Receptors Laboratory at the Monash Biomedicine Discovery Institute.

Image credit: ©stock.adobe.com/au/Pixel-Shot

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