Anthrax Toxin

Dear Colleagues,

Bacillus anthracis three component toxins have been discovered 65 years ago, but their role in anthrax pathogenesis has been slowly unveiled. Anthrax toxins are formed by the association of three nontoxic factors. These three factors are the protective antigen (PA), which is the ‘binding’ factor orchestrating the entry into the cell, and the lethal factor (LF) and edema factor (EF) which bear respectively a toxic activity (metalloprotease and adenylate cyclase). Intravenous injections of PA + LF (lethal toxin, LT) have been shown to be lethal in several animal models, while intradermal injections of PA + EF (edema toxin, ET) induce edema in the subcutaneous tissues. Crystal structures have been obtained for all three components. Two cell receptors have been proposed and their ubiquitous expression explains the diverse effects of toxins on vertebrate cells. The biochemical and cellular mechanisms of entry have been described, although numerous questions still remain. The list of intracellular toxin targets is constantly growing, suggesting that we only see the tip of the iceberg. At a larger scale, the toxin effects vary from innate and adaptive immune system impairment to vascular shock, largely participating in the virulence. The large corpus of knowledge on anthrax toxins gathered over the last decades has allowed developing medical countermeasures such as chemical inhibitors and monoclonal antibodies. Moreover, the PA forms still the pillar of all anthrax vaccines emphasising the scientific interest of anthrax toxins.

This special issue of ‘Toxins’ intends to cover all aspects of anthrax toxin biology from the basic science up to the medical applications. It is expected to reflect as accurately as possible the vivid aspects of the field.

Dr. Jean-Nicolas Tournier
Guest Editor