ALTERATIONS IN THE BIOLOGICAL ACTIVITY OF PROTECTIVE ANTIGEN OF BACILLUS ANTHRACIS TOXIN
Abstract
The toxin of Bacillus anthracis contains at least three known components - protective antigen (PA), edema factor (EF), and lethal factor (LF) - that can be assayed by the agar diffusion technique. None of the components is toxic when tested alone, but combination of PA with either EF or LF produces, respectively, the edema reaction (deter mined in guinea pigs) or lethality (determined as the time to death of Fischer 344 rats). Sev eral preparations of partially purified PA failed to kill rats when combined with LF, although they were serologically indistinguishable from samples of active PA. Recently this loss in lethal activity has been observed in vivo along with a transient conversion of PA to an inhibitor of toxin lethality. The exact nature of the change or changes is unknown but probably involves subtle physico-chemical changes rather than extensive splitting of the molecule. The lethality of toxic mixtures was inhibited in vitro by low levels of altered PA and by high levels of active PA. These ats aredusse in relationship to the cleance from the bloodstream of injected whole toxin or its components, and a possible role of PA in anthrax therapy is sugested.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 1963
- Accession Number
- AD0410154
Entities
People
- Dorothy M. Molnar
- Robert A. Altenbern
Organizations
- United States Army Biological Warfare Laboratories