New antibody 'can neutralise influenza viruses in a unique way'

A new antibody has been found by US researchers which they believe can neutralise influenza viruses in a unique way.

Scientists at the Scripps Research Institute and Sea Lane Biotechnologies have revealed the co-crystal structure of a new human antibody which can recognise the crucial structure that flu viruses use to attach to host cells.

This structure was previously thought to have been too small for an antibody to grab onto effectively. However, the new research shows that an immune protein can hit this precise spot by using just a small part of its target-grabbing apparatus, and in doing so, neutralize a broad range of dangerous flu viruses.

Ian A. Wilson, the Hansen Professor of Structural Biology at Scripps Research, said: "This highly focused binding to the receptor binding site using only a single loop on the antibody has never been seen before, and it’s really fascinating; it gives us some good ideas about designs for vaccines and therapies."

The researchers at Sea Lane Biotechnologies began by collecting bone marrow from patients who had been exposed to certain key strains of flu. The bone marrow acts like a 'fossil record' of all antibodies a person has ever made, and therefore the scientists were confident that the antibodies they were looking for would be there.

Using the internationally and locally collected bone marrow, Sea Lane generated a 'comprehensive flu library' of billions of antibodies.
They isolated the single antibody they were looking for, dubbed CO5, by screening this library.

Through further tests, they found that relatively low doses of CO5 prevented infections in mice, despite influenza A exposures that would have been lethal. They also found that the antibody worked as a therapy too, rescuing 100 per cent of mice when administered up to three days after a flu infection had begun.

Their findings were reported in the journal Nature.