Adults who have recovered from the potentially deadly H5N1 strain of avian influenza may hold the key to future treatments for the virus, according to a team of researchers.
In a study (published in PLoS Medicine), researchers have shown how specific antibodies taken from bird flu survivors can be reproduced in the laboratory and prove effective at neutralising the virus in culture vitro and in mice.
Preventing infection and neautralising the virus
Doctors based at the Hospital for Tropical Diseases in Vietnam, the Institute for Research in Biomedicine in Switzerland, and the National Institute of Allergy and Infectious Diseases in the US, 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.
The researchers discovered that the antibodies provided significant immunity to mice that were subsequently infected with the Vietnam strain of H5N1. This significantly reduced 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.
Clinical benefit to humans
“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 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.”
“We can’t say for certain that a pandemic influenza virus will resemble the H5N1 strain that we have been studying or that the monoclonal antibodies generated using our technique will be able to tackle such a virus,” says Professor Lanzavecchia. “Nevertheless, we are encouraged by the broad neutralizing activity of these antibodies in the lab and the moderate doses required.”