Scientists from The Scripps Research Institute and Sea Lane Biotechnologies have solved the co-crystal structure of a human antibody that can neutralize influenza viruses in a unique way. The antibody recognizes the crucial structure that flu viruses use to attach to host cells, even though previously this structure had been thought too small for an antibody to grab effectively. The immune protein manages to hit this precise spot by using just a small part of its target-grabbing apparatus. In so doing, it can neutralize a broad range of dangerous flu viruses.
Researchers at Sea Lane Biotechnologies began by collecting bone marrow from patients who had been exposed to certain key strains of flu. Because the bone marrow is a “fossil record” of all the antibodies a person has ever made, they felt confident that the antibodies they were looking for would be there. Sea Lane generated a “comprehensive flu library” of billions of antibodies. Researchers then isolated the unusual new antibody, which they dubbed C05, by screening this library for antibodies that could bind to proteins from a variety of influenza A viruses.
C05 protected cells in the lab dish from infection by these viruses. In mice, relatively low doses of C05 prevented infections despite influenza A exposures that otherwise would have been lethal. Further tests revealed the curious property of C05: it specifically recognizes and blocks the part of the flu virus that mediates viral attachment to host cells.
The fact that C05 can make such a precision grab suggests it could contribute to antibody-based therapies for severe influenza infections. A universal flu vaccine also might be more effective if it were designed to elicit such antibodies in people. Read more in the Scripps Research Institute press release.
