Avian influenza survivors´ antibodies effective in neutralizing H5N1 strain

Adults who have recovered from the potentially deadly H5N1 strain of avian influenza may hold the key to future treatment for the virus, according to an international team of researchers.

In a study published Monday in the open access journal PLoS Medicine, the researchers have shown how specific antibodies taken from avian flu survivors in Vietnam can be reproduced in the laboratory and prove effective in neutralizing the virus in cultured vitro and in mice.

Doctors based at the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam, the Institute for Research in Biomedicine in Switzerland and the National Institute of Allergy and Infectious Diseases in the United States, have shown that monoclonal antibodies generated from blood of human survivors of the H5N1 virus are effective at both preventing infection in mice and neutralizing the virus in those already infected.

The research had been fast-tracked for funding by Britain"e;s Wellcome Trust and is also supported by grants from the National Institutes of Health in the United States and the Swiss National Science Foundation.

The researchers found that the antibodies provided significant immunity to mice that were subsequently infected with the Vietnamese strain of H5N1. This reduced significantly the amount of virus found in the lungs and almost completely prevented the virus from 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 neutralize infection by the H5N1 "e;bird flu"e; virus in mice," said Dr. Cameron Simmons, a Wellcome Trust researcher at the Oxford University Clinical Research Unit in 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," Simmons said.

The antibodies were discovered in the laboratory of Pro. Antonio Lanzavecchia at the Institute for Research in Biomedicine. The researchers used a new technique that allows them to rapidly reproduce human monoclonal antibodies starting from a small sample of blood.

Source: Xinhua