A series of peptides discovered by scientists, present on the internal structure of influenza viruses could lead to the development of a universal influenza vaccine.
Influenza, an acute viral infection, affects hundreds of thousands of people a year and puts an enormous strain on healthcare providers globally. The last pandemic flu outbreak in the UK - swine flu - was in 2009 when it claimed 457 lives. While previous pandemics have been more serious, there is a heightened risk of more severe pandemics in the future.
For the latest study, researchers at the University of Southampton, University of Oxford and Retroscreeen Virology Ltd used a research method known as "Human Viral Challenge Studies", where healthy volunteers are infected with influenza virus, and their immune responses closely monitored in an isolation unit.
These were important to the research, as they allowed the healthy volunteers to be held in "sterile" isolation conditions and ensured they had no existing infections. The volunteers were then "challenged" with influenza virus, with blood samples being taken at regular intervals to observe how their immune systems responded to the viral infection.
Researchers discovered that the immune systems produced various types of T-cells (part of the immune system that kills both viral particles, and cells infected with viral particles). Notably, the T-cells responded to peptides associated with the internal structures of the influenza viruses.
Unlike the external structures of influenza virus, that mutates very rapidly and creates a new strain of virus most years, the internal structures change very slowly over a long period of time. These internal structures are found in all strains of influenza virus - thus, a vaccine that targets such peptides may provide immunity against all strains of influenza, including seasonal (yearly), avian (bird), and swine flu, for many years.
A vaccine against these peptides would activate the T-cell immune response - which is able to respond much more rapidly than vaccines that activate an antibody response.
"We have found that there is an important role for T-cells that recognise the flu virus, which if harnessed could protect against most or even all strains of seasonal and pandemic flu," said Dr Tom Wilkinson, Senior Lecturer in Respiratory Medicine at the University of Southampton, who led the study.
"Through this discovery we hope to improve vaccines for future strains of influenza; and potentially protect against the next pandemic. However there is more to do to translate these findings into new approaches to treatment," he added.
The discovery was published online in Nature Medicine.