Antibodies produced by people who recovered from H1N1 offer clues for universal flu vaccine

The antibodies produced by individuals who fought off H1N1 (swine flu) infection last year may bring researchers one step closer to their quest to develop a "universal" flu vaccine, U.S. researchers said Monday, HealthDay News/Bloomberg Businessweek reports. As the researchers from Emory University and the University of Chicago report in the Jan. 10 issue of the Journal of Experimental Medicine, "people who were infected with the H1N1 virus and recovered had a special immune response, producing antibodies that protect against a wide variety of flu strains," the news service writes (1/10).

For the study, the team of researchers analyzed nine patients between 21 and 45 who had contracted H1N1 last year, suffering "effects that ranged from a mild illness lasting only a few days to severe symptoms that required two months in hospital," the U.K. Press Association reports. "Genes isolated from white blood cells taken from the patients were used to produce an assortment of 86 antibodies in the laboratory," according to the news service (1/10).

The researchers then tested how the antibodies responded to different flu strains, according to Reuters. "Of these, five were cross-protective, meaning they could interfere with many strains of flu including the 1918 'Spanish flu' and a strain of H5N1 or avian flu," the news service writes. "Tests of these antibodies in mice showed they were fully protected from an otherwise lethal dose of flu." Additionally, "some of these cross-protective antibodies were similar in structure to those discovered by other teams as having potential for a universal flu vaccine," Reuters writes (Steenhuysen, 1/10).

"The 2009 H1N1 virus matched typical influenza strains only in the components that are absolutely critical for the virus to function," according to a University of Chicago Medical Center press release. (1/10).

"Designing flu vaccines usually involves an evolutionary arms race as scientists try to match the virus's ability to mutate into new forms," the UKPA continues, adding that "[t]he broad-spectrum antibodies obtained from the swine flu patients appear to target the 'stalk' region whose structure has remained much the same for nearly a century."

"Previously, this type of broadly protective, stalk-reactive antibody was thought to be very rare," study co-author Jens Wrammert of Emory University said, according to the news service. "In contrast, in the patients we studied, these stalk-reactive antibodies were surprisingly abundant," Wrammert said (1/10).

"The result is something like the Holy Grail for flu-vaccine research," Patrick Wilson of the University of Chicago, who was a co-author of the study, said according to Agence France-Presse. "It demonstrates how to make a single vaccine that could potentially provide immunity to all influenza. The surprise was that such a very different influenza strain, as opposed to the most common strains, could lead us to something so widely applicable," Wilson said (1/10).

"The researchers believe the 'extraordinarily' powerful antibodies were created as the body learned how to fight the new infection with swine flu using its old memory of how to fight off other flu viruses," BBC reports. "Next they plan to examine the immune response of people who were vaccinated against last year's swine flu but did not get sick to see if they too have the same super immunity to flu," the news service adds.

The article adds comments on what the findings might mean for the future of universal flu vaccine development by Sarah Gilbert, who studies viruses at Oxford University (Roberts, 1/10).

Reuters adds details on future steps for the research team as well as the ongoing efforts by the National Institutes of Health to develop a universal flu vaccine (1/10).