A researcher at UCC is studying a vaccine that could protect against any form of influenza, including bird flu, informed by earlier work on a two-step anti-malaria vaccine, writes Dick Ahlstrom
RESEARCHERS working to find a vaccine against the dangerous bird flu virus are borrowing an idea from boxing - that a one-two combination punch can win the day. They have devised a two-step vaccine that should work not just against bird flu but against any form of the influenza virus.
A collaborative effort is under way involving researchers from Britain, France, the US and Ireland, and such a vaccine could possibly be ready for use within three years, explains Dr Anne Moore, who heads the Irish research team. The great advantage of the approach being used is that human trials can begin immediately, even as she studies how the vaccine works, she says.
Moore heads the immunology group within University College Cork's school of pharmacy. Her role is to explain the biochemistry behind the idea. It is based on giving an initial vaccine to sensitise the patient against influenza, followed by a second, very different flu vaccine that produces a strong immune response against all types of the virus.
A high level of safety is assured, given that the first jab involves the adenovirus, a well-understood organism responsible for the common cold, and the second involves the poxvirus, long used in vaccines against diseases such as smallpox, she says.
The two-step approach was informed by earlier collaborative work by an international team including UCC, which reported progress towards a promising malaria vaccine in the journal Nature Medicine.
The new malaria vaccine used this one-two combination and the idea was then carried across to a project including the University of Oxford funded by the UK's Medical Research Council and the Wellcome Trust and UCC, funded here by the Health Research Board.
Oxford is overseeing the human trials, which could begin next summer, Moore says. These patients would then be challenged with live flu within the following year.
Meanwhile, her team is studying the complex biochemistry behind the two-step approach. "For reasons we don't understand, some of these viral platforms are very good at boosting the immune response while others work on building immune memory," she says. "We are working on the mechanism of protection and trying to understand it."
If invaded by a virus our immune system produces antibodies to clear the virus and also imprints a memory of the organism in special central memory "T-cells" located mainly in the lymph nodes, Moore explains. You need a strong immune memory to produce the "effector" cells that release fresh antibodies should the invader ever return.
The adenovirus is particularly good at producing a powerful immune memory and this can be targeted against flu by building a harmless piece from the surface of the flu virus into the adenovirus, she says.
Flu is notorious for changing its surface proteins, however, which is why every year we need a new kind of vaccine. The researchers got around this in the malaria vaccine and now with flu by using the poxvirus. It is engineered to carry harmless but essential pieces from inside the flu virus, parts of the virus that never change.
They found in the case of malaria that once the immune memory was in place the second vaccine strongly boosted the immune response. This should also work with flu, and because the poxvirus vaccine includes essential bits found in every type of influenza, it means the person should be vaccinated against any kind of flu including the dangerous H5N1 bird flu, Moore says. "This means you can stockpile just one vaccine instead of trying to hold seasonal vaccines," she says.
They are studying these complex processes, but the trials can go ahead independently because all parts of the vaccine are known to be safe for humans.