In the 2001 attack in which anthrax spores were mailed to members of Congress and reporters, some anthrax-exposed individuals were given antibiotics but not the existing anthrax vaccine, because it requires six injections over a period of six months and may cause adverse reactions.
In the new study, the U-M team combined the nanoemulsion and a recombinant protein of Bacillus anthracis to make the vaccine, which they gave first to mice in either one or two applications. They found the animals developed several types of effective immune response. The vaccine produced both systemic and cellular immunity, meaning that the body produces antibodies and primes specific cells throughout the body to fend off anthrax infection. The vaccine also induced immunity on the mucous membranes of the nose and lungs, where inhaled anthrax spores enter the body and start a process that can cause illness and death.
We saw protective immunity in the animals after only two administrations rather than six, says James R. Baker, Jr., M.D., director of the Michigan Nanotechnology Institute for Medicine and Biological Sciences and the senior author of the study. He is the Ruth Dow Doan Professor in the Department of Internal Medicine and chief of the Division of Allergy and Clinical Immunology in the U-M Medical School.
After administering the vaccine, the researchers challenged the immune systems of immunized guinea pigs with injections of 1,000 times the lethal dose of Bacillus anthracis spores. All the animals survived, whereas none of the control animals did.
When the researchers delivered large doses of Bacillus anthracis spores directly into the animals nasal tissue, they found that 40 percent to 70 percent of the immunized animals survived.
Because of the biosafety restric
|Contact: Kara Gavin|
University of Michigan Health System