Super antibody for flu

A ‘super antibody’ against flu has been identified by scientists offering hope of a universal jab that could wipe out the infection.

The breakthrough is a major step forward in developing a long-term ‘cure’ rather than an annual winter vaccination.

The jab could also be used in severe infections or to protect hospital staff during an outbreak, saving millions of lives.

Scientists have identified three human antibodies which protect against the influenza B strain and one, called CR9114, which also protects against the more commmon and serious influenza A virus.

Structural biologist Professor Ian Wilson, of the Scripps Research Institute, La Jolla, California, said: ‘To develop a truly universal flu vaccine or therapy, one needs to be able to provide protection against influenza A and influenza B viruses, and with this report we now have broadly neutralizing antibodies against both.’

Referring to CR9114 Prof Wilson, whose findings are published online in Science Express, said: ‘It is the only one in the world that we know of that has been found to do this.’

He and co researchers at the Crucell Vaccine Institute in Leiden in the Netherlands generated a large collection of flu antibodies from the immune cells of volunteers who had been given a seasonal jab.

They then screened them to find those that could bind to a wide variety of influenza B viruses.

Flu vaccination
Flu vaccination

Three of the antibodies – known as CR8033, CR8071 and CR9114 – protected mice against normally lethal doses of the two major strains.
And CR9114 also fought off influenza A viruses, including the H1N1 subtype that killed about 17,000 people in a 2009 pandemic.

The researchers used state of the art scanning techniques to show that the antibodies, CR8033, CR8071, attach themselves to the ‘head’ of the hemagglutinin protein, which studs the outer surface of flu viruses preventing them from moving on from infected cells.

Dr Nick Laursen, a research associate in Prof Wilson’s laboratory, said: ‘The unique thing about these two antibodies is they neutralize flu viruses chiefly by preventing virus particles from exiting infected cells.’

Antibody CR9114 turned out to bind to a site on the hemagglutinin stem.

Study lead author Dr Cyrille Dreyfus, another member of Prof Wilson’s team, said: ‘It prevents the hemagglutinin protein from undergoing the shape-change needed for the virus to fuse to the outer membrane of a host cell.

‘This appears to be a real weak point of the virus.’

In a study published in 2009 Prof Wilson’s laboratory determined the structure of another antibody that broadly neutralizes influenza A viruses by binding to essentially the same site on the hemagglutinin stem but in a slightly different way so it fails to get a grip on influenza B.

Prof Wilson said: ‘With some tweaking of that antibody’s binding domains, we might have been able to get a broader effect like CR9114’s.’

Dr Jaap Goudsmit, of the Crucell Vaccine Institute, said: ‘As we move towards design of a universal flu vaccine, we need to find more inclusive assays to screen for antibodies such as CR9114, which may be highly effective but have novel mechanisms for neutralization that cannot be detected by the current methods used in influenza vaccine development.’

Flu antibody discovered

The first antibody which can fight all types of the influenza A virus has been discovered, researchers claim.

Experiments on flu-infected mice, published in Science Express, showed the antibody could be used as an “emergency treatment”.

It is hoped the development will lead to a “universal vaccine” – currently a new jab has to be made for each winter as viruses change.

Virologists described the finding as a “good step forward”.

Many research groups around the world are trying to develop a universal vaccine. They need to attack something common to all influenza which does not change or mutate.

It has already been suggested that some people who had swine flu may develop ‘super immunity’ to other infections.

Scientists from the Medical Research Council’s National Institute for Medical Research at Mill Hill and colleagues in Switzerland looked at more than 100,000 samples of immune cells from patients who had flu or a flu vaccine.

They isolated an antibody – called FI6 – which targeted a protein found on the surface of all influenza A viruses called haemagglutinin.

Flu jab
Flu jab

Sir John Skehel, MRC scientist at Mill Hill, said: “We’ve tried every subtype of influenza A and it interacts with them all.

“We eventually hope it can be used as a therapy by injecting the antibody to stop the infection.”

Professor Antonio Lanzavecchia, director of the Institute for Research in Biomedicine, Switzerland, said: “As the first and only antibody which targets all known subtypes of the influenza A virus, FI6 represents an important new treatment option.”

When mice were given FI6, the antibody was “fully protective” against a later lethal doses of H1N1 virus.

Mice injected with the antibody up to two days after being given a lethal dose of the virus recovered and survived.

This is only the antibody, however, not the vaccine.

A vaccine would need to trigger the human body’s immune system to produce the antibody itself.

Sir John said the structure of the antibody and how it interacted with haemagglutinin had been worked out, which would help in the search for a vaccine, but that was “definitely years away”.

Professor John Oxford, a virologist at Queen Mary, University of London, said: “It’s pretty good if you’ve got one against the whole shebang, that’s a good step forward.”