Bird Flu survivors' blood may combat deadly H5N1virus

An international team of researchers on Monday reported that blood taken from survivors of the extremely infectious H5N1 bird flu virus could provide a new therapy for the hard-to-treat strain of bird flu virus, turning a long time suspicion that culling immune-system molecules from survivors could provide a new therapy for the deadly disease into reality.

After analyzing the blood donated by four Vietnamese survivors of the H5N1 bird flu virus to the Hospital for Tropical Diseases in Ho Chi Minh City, scientists identified antibodies that may protect humans from contracting the lethal strain.

Researchers first developed a way to cull antibody-producing cells from the donated blood, and then kept them manufacturing the molecules in the laboratory. Then they performed testing on thousands of the antibodies in order to find the ones with the ability to kill the H5N1 virus.

Use of human monoclonal antibodies, immune system proteins, to treat the disease is not a novel technique, instead these antibodies have been used to treat or prevent various other infections, including hepatitis, rabies and respiratory syncytial virus. Now researchers have identifies immune system proteins that can recognize the H5N1 virus.

Antibodies are the proteins found in the human immune system that help the body fight foreign invaders, especially pathogens and toxins.

Although, the research showed these immune system proteins’ benefits in mice so far, researchers believe their finding may provide a new way to treat bird flu infections in people and another potential weapon to stockpile ahead of a feared pandemic of avian influenza.

According to the researchers blood taken from four Vietnamese survivors of the H5N1 bird flu virus protected mice from a number of strains of the virus.

In the experiments, the scientists injected the mice with antibodies generated from the blood of Vietnamese avian flu survivors. The mice were then exposed to the same strains that proved life-threatening in humans. Mice injected with the H5N1-targeting antibodies were completely survived, while mice given the non-H5N1 antibodies died, according to the study.

"We have shown that this technique can work to prevent and neutralize infection by the H5N1 bird flu virus in mice," said Dr. Cameron Simmons, of the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam.

The breakthrough findings have augmented scientists’ hope for developing a vaccine against a possible global H5N1 pandemic. Scientists are gathering at the end of this week in Paris for the second International Conference on Avian Influenza in Humans.

Besides Simmons and colleagues, the international team of researchers included Dr. Kanta Subbarao of the National Institute of Allergy and Infectious Diseases and Dr. Antonio Lanzavecchia of the Institute for Research in Biomedicine in Bellinzona, Switzerland.

"The four adult blood donors in this study were diagnosed with highly pathogenic avian influenza H5N1 infection between January 2004 and February 2005 at the Hospital for Tropical Diseases in Ho Chi Minh City, Vietnam," the researchers wrote in their study.

The extremely infectious H5N1 virus continues to spread like wild fire through Vietnam’s poultry stocks, making it one of the countries hardest hit by the virus with 42 human fatalities since 2003.

Most human infections have occurred after contact with birds infected with H5N1 virus, which according to the Geneva-based WHO is generally not harmful to humans, but scientists now fear the deadly H5N1 strain could mutate and become easily transmissible among people, leaving millions more to die and triggering a devastating human pandemic.

H5N1, also known as A(H5N1), is a subtype of the Influenza A virus that is capable of causing illness in many animal species, including humans, while a bird-adapted strain of H5N1, called HPAI A(H5N1) for "highly pathogenic avian influenza virus of type A of subtype H5N1", is the causative agent of H5N1 flu, commonly known as "avian influenza" or simply "bird flu", and is endemic in many bird populations, especially in Southeast Asia.

According to the WHO data, the strain of bird flu virus has so far infected 307 people and killed 186 of them, mostly in Southeast Asia, it began ravaging Asian poultry stocks in 2003.

WHO, Food and Agriculture Organization (FAO), World Organization for Animal Health (OIE) in collaboration with United States are looking into minimizing the risk of spreading of this disease and taking steps to avoid this to turn into a pandemic on a global level.