Scientists have taken a step towards developing a 'universal' flu vaccine that could be produced more quickly and offer broader protection than the virus-specific inoculants available today.
The approach by a team led by bio-engineer James R Swartz from Stanford University, arises from a better understanding of the structure of a key protein on the surface of the flu virus, and a new process for making vaccines based on that understanding.
A flu virus is made up of different proteins. Protruding from the surface of the virus are hundreds of copies of a protein called Hemagglutinin (HA).
Swartz and colleagues base their new vaccine approach on the understanding that, whereas the head of the flu virus varies from year to year, the protein stem remains more constant over time.
Theoretically, a vaccine based on the stem should be more broadly protective against different strains of flu, and perhaps offer universal protection.
Moreover, since the stem remains relatively constant from year to year, once our immune systems produces antibodies against that antigen, multi-season protection might be possible.
But this approach remains experimental and has not yet been tested on patients.
The study focused on the first step in developing such a universal vaccine: creating a protein stem fragment that could be injected into the blood stream, in short, creating a target, or antigen, to attract the attention of our immune system and trigger an effective defense.
The researchers began with a section of DNA that contained the instructions for making the protein structure for one important strain of flu, the H1N1 virus that caused the pandemic of 1918 and recurred in milder form in 2009.
They started with the DNA sequence that defines the entire HA protein, both head and stem.
They then subtracted the DNA coding for the head. Thus, their edited DNA strand only contained the instructions for making the protein stem.
The team used a relatively new and experimental process to manufacture the viral stem. This process is called cell free protein synthesis (CFPS).
Researchers created and refined a viral protein stem that would be useful as an experimental vaccine antigen.
The research was published in the journal Proceedings of the National Academy of Sciences.
