HomeFeaturesDailyBriefingsRapidReconSpecial ReportsAbout Us

Mice Cured of Bird Flu Using Human Antibodies - Strides made in fight against bird flu

As time passes, the reality (or possibility) of the threat posed by a mutation of H5N1 making the jump to humans has increased the attention being paid to the progress being made. It was recently announced that a collaborative international team of scientists from the National Institute of Allergy and Infectious Diseases (NIAID), the Institute for Research in Biomedicine, Bellinzona, Switzerland and the Oxford University Clinical Research Unit, Hospital for Tropical Diseases, Ho Chi Minh City, Vietnam, had used antibodies derived from immune cells from recent human survivors of H5N1 avian influenza to successfully treat H5N1-infected mice as well as protect them from an otherwise lethal dose of the virus.

"The possibility of an influenza pandemic, whether sparked by H5N1 or another influenza virus to which humans have no natural immunity, is of serious concern to the global health community," says NIAID Director Anthony S. Fauci, M.D. "If the success of this initial study is confirmed through further laboratory and clinical trials, human monoclonal antibodies could prove to be valuable therapeutic and prophylactic public health interventions for pandemic influenza."

While this is not a new approach since it was used in treating victims during the 1918-1919 influenza outbreak, scientists had been struggling to do the same with bird flu. The process is known as passive immunotherapy, the new approach relies on two distinct steps: the extraction and culturing of antibody-producing white blood cells known as Memory B cells, and the purification of the B cells to isolate four distinct monoclonal antibodies (mAbs) that secrete bird flu neutralizing antibodies. Tests showed that mice receiving either of the two protective mAbs had levels of virus in their lungs that were 10 to 100 times lower than those in control mice, and little or no virus moved beyond the lungs. The mouse study is ''a very lovely, elegant proof of principle,'' said Dr. William Schaffner, a flu expert at Vanderbilt University.

After taking blood samples from Vietnamese adults who were confirmed to have an H5N1 infection, researchers extracted white blood cells (called memory B cells) and treated them to cause them to produce large amounts of antibody. The samples of antibody materials were then tested to identify those that could neutralize the H5N1 influenza virus, and then the B cells were purified to create four monoclonal antibodies (mAbs) that secrete H5N1-specific neutralizing antibodies. Skipping through most of the technical biomedical discussion that I don’t understand, the test mice were given one of two different H5N1 mAbs at one of three dosages or a human mAbs for diphtheria or anthrax. All of the test mice were then exposed to lethal doses of H5N1 influenza virus. The mice that were given the non-H5N1 mAbs died within a week. Comparatively, the survival rate of mice receiving one of the H5N1 antibodies was remarkable.

What does all of this mean? The implications are:

► researchers say, that human mAbs may provide broad protection against variant H5N1 viruses--a desirable quality in any therapeutic aimed at the constantly evolving flu virus.

► the findings from this international collaboration are encouraging

► the neutralizing ability of fully human mAbs with potent H5N1 influenza virus…can be rapidly generated from the blood of convalescent patients

Big Pharma Donates Vaccines
GlaxoSmithKline to make unprecedented vaccine donation to WHO pandemic flu stockpile
GlaxoSmithKline (GSK) today announced its intention to donate 50 million doses of H5N1 adjuvanted pre-pandemic influenza vaccine to the World Health Organization (WHO) in support of its stockpile initiative.

Sanofi Pasteur Supports WHO Initiative for the Establishment of an H5N1Vaccine Stockpile.
Sanofi said it, too, was ready to supply a significant number of doses of H5N1 vaccine for an international stockpile through a WHO partnership. Part of this supply could be made available immediately, in bulk form.

Baxter, Glaxo to donate flu vaccine
GlaxoSmithKline PLC will donate enough prepandemic influenza vaccine to the World Health Organization to inoculate 25 million people in poor countries, and Deerfield-based Baxter International Inc. said it also will donate vaccine.

The United Nations agency said on its Web site Wednesday that it will get 50 million doses to distribute in the event of a pandemic caused by the deadly H5N1 flu virus. WHO said Sanofi-Aventis SA and Hungary's Omnivest also might make some vaccine available.

The question remains if having this stockpile of pre-pandemic flu vaccine will do much if the H5N1 morphs as expected before it jumps to humans. For that reason, keeping an eye on research like that done on the mice by the NIAID/International consortium. I continue to follow this subject because of the implications on preparedness and response, and the concerns in some circles that an outbreak could be quite devastating.

Notes