Description
Anthrax, a zoonotic disease caused by the spore-forming bacterium Bacillus anthracis, has become a biological warfare agent of concern due to the stability and extreme lethal consequences of human inhalation of spores. Exposure to infected animals or tissue is also a major safety concern. The disease can occur in three forms: cutaneous, gastrointestinal and inhalation. Spores can remain viable and infective in the soil for many years. B. anthracis evades the immune system by producing an anti-phagocytic capsule. In addition, three proteins - protective antigen (PA), lethal factor (LF), and edema factor (EF) – are produced that act in combinations to form two exotoxins known as lethal toxin and edema toxin. Development of improved vaccines for protection of livestock and for human immunization have involved preparations that include combinations of these antigens. Immunoassays that measure titer of host antibody directed against the specific B. anthracis antigens (PA83/LF/EF can be used to study the efficacy of anthrax vaccines and the exposure to the bacterium and/or separate antigens