Antibodies Neutralized H5N1 Strain

Picture: An avian influenza A virion

Antibodies from survivors help
fight the virus; © PHIL

The H5N1 influenza virus has caused disease and death in millions of poultry across the globe and occasionally has been transmitted to humans, often fatally. By mid-May 2007, according to the World Health Organization, there had been 306 known cases in humans, 185 of them fatal.

Now researchers have shown that monoclonal antibodies generated from blood of human survivors of the H5N1 virus are effective at both preventing infection in mice and neutralising the virus in those already infected. They found that the antibodies provided significant immunity to mice that were subsequently infected with the Vietnam strain of H5N1. This reduced significantly the amount of virus found in the lungs and almost completely prevented the virus reaching the brain or spleen. In those people in Vietnam who died from the H5N1 strain, the virus was found to have spread from the lungs; this was not the case in those who survived.

"We have shown that this technique can work to prevent and neutralise infection by the H5N1 'bird flu' virus in mice," says Dr Cameron Simmons, a Wellcome Trust researcher at the Oxford University Clinical Research Unit, Vietnam. "We are optimistic that these antibodies, if delivered at the right time and at the right amount, could also provide a clinical benefit to humans with H5N1 infections."

"In particular, we found that it was possible to administer the treatment up to 72 hours after infection. This is particularly important as people who have become infected with the virus do not tend to report to their local healthcare facilities until several days after the onset of illness."

The researchers used a new technique that allows them to rapidly reproduce human monoclonal antibodies starting from a small sample of blood.; Source: Wellcome Trust