Researchers aim to improve anthrax vaccine

SEATTLE – A research team has been awarded a $3.5 million federal grant to use a molecular detective technique to study and potentially improve the military’s anthrax vaccine.

The grant to the Benaroya Research Institute was one of 14 announced Monday in a $74 million program by the National Institute of Allergy and Infectious Diseases to develop better vaccines or medications for use against infectious agents.

The team headed by Dr. Gerald T. Nepom, director of the private, nonprofit institute at Virginia Mason Hospital, has developed artificial molecules called “tetramers” for the anthrax vaccine research.

Last Wednesday a federal judge ordered the Pentagon to stop requiring that military personnel get inoculated against anthrax, a bacteria that can be used as a bioterrorism or germ warfare agent.

Service personnel sued the Defense Department, arguing that the vaccine was rushed through approval before the Iraq war and claiming evidence indicates it has caused immune illnesses in a significant number of soldiers.

Defense Secretary Donald Rumsfeld has maintained that the “vaccine is safe and effective,” but many scientists view it as crude and cumbersome to administer.

The vaccine is produced under government contract by Bioport Inc. of Lansing, Mich., using the centuries-old technique of filtering killed bacteria. It is administered in six injections over 18 months and must be repeated regularly to maintain immunity.

Nepom and Dr. William W. Kwok, principal investigator on the Benaroya project, believe their engineered molecule provides a streamlined, more accurate test that could soon point the way to a better vaccine.

The effectiveness of most vaccines is measured in terms of production of antibodies, cells created in the blood to attack invading disease agents – a test Nepom said is slow, indirect and incapable of evaluating the level of protection.

“It’s like following footprints in the sand rather than watching someone as they run by,” he said.

With tetramers, named for four “arms” that grab T-cells which direct the antibodies, scientists can directly monitor the impact of the vaccine, Nepom said.

“This is the first method to do this,” he added.

To be effective, a vaccine must trigger the body’s immune system to resist disease. The more precise the immune system’s response, the less risk there is of side effects such as damage to healthy cells.

Nepom’s team created tetramers that mimic the parts of T-cells which recognize specific disease agents ranging from flu viruses to anthrax bacteria. Specific tetramers latch onto T-cells generated by a vaccine to fend off a specific disease.

Once a tetramer and T-cell bond, the tetramer fluoresces, literally lighting up for detection by specialized lasers.

Nepom explained that one drop of blood contains about a million T-cells which target as many as 250,000 different viral or bacterial invaders, so without tetramers scientists were unable to track T-cells directly.

“Before this method, this was really a needle-in-the-haystack problem,” Nepom said.