H1N1 pandemic flu strain ‘key to universal vaccine’

WASHINGTON - Scientists from Emory University School of Medicine and the University of Chicago have found that the 2009 H1N1 pandemic flu strain could be the key to a universal vaccine.

“Our data shows that infection with the 2009 pandemic influenza strain could induce broadly protective antibodies that are only rarely seen after seasonal flu infections or flu shots,” said Jens Wrammert.

“These findings show that these types of antibodies can be induced in humans, if the immune system has the right stimulation, and suggest that a pan-influenza vaccine might be feasible.”

The antibodies from those who were infected by H1N1 could guide researchers in efforts to design a vaccine that gives people long-lasting protection against a wide spectrum of flu viruses, say the researchers.

Next, the research team is planning to examine the immune responses of people who were vaccinated against the 2009 H1N1 strain but did not get sick.

The team of researchers identified white blood cells from the patients that made antibodies against flu virus, and then isolated the antibody genes from individual cells. They used the genes to produce antibodies in cell culture-a total of 86 varieties-and then tested which flu strains they reacted against.

Five antibodies isolated by the team could bind all the seasonal H1N1 flu strains from the last decade, the devastating “Spanish flu” strain from 1918 and also a pathogenic H5N1 avian flu strain.

“Previously, this type of broadly protective, stalk-reactive antibody was thought to be very rare. In contrast, in the patients we studied, these stalk-reactive antibodies were surprisingly abundant,” said Wrammert.

Two antibodies could protect mice against an otherwise lethal dose of any of the three strains, even when the antibody was given 60 hours after infection. However, one antibody only protected against the 2009 H1N1 strain.

The antibody that only reacted to the 2009 H1N1 strain came from the patient with the most severe illness.

“The result is something like the Holy Grail for flu-vaccine research,” said Patrick Wilson.

“It demonstrates how to make a single vaccine that could potentially provide permanent 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.”

The results were published online Monday in the Journal of Experimental Medicine. (ANI)