Anthrax virulence factors

B anthracis possesses three known virulence factors an antiphagocytic capsule and two protein exotoxins, called the lethal and the edema toxins. The role of the capsule in pathogenesis was demonstrated in the early 1900s, when anthrax strains lacking a capsule were shown to be avirulent.17 In more recent years, the genes encoding synthesis of the... 

It was Koch, in his initial studies on anthrax, who first suggested the importance of toxins. In 1954, Smith and Keppie20 demonstrated a toxic factor in the serum of infected animals that was lethal when injected into other animals. The role of toxins in virulence and immunity was firmly established by many workers in the ensuing years.21-23 Advances in molecular biology in the last decade have produced a more complete understanding of the biochemical mechanisms of action of the toxins and have begun to provide a more definitive picture of their role in the pathogenesis of the disease. 

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