Summary
Anthrax toxin, is secreted by the anthrax bacterium and is made up of toxic proteins that damage host cells. In 2001 the intentional release of anthrax spores in postal mail in the US has led to increased federal research dollars to design possible new therapeutics and vaccines to prevent or treat these toxins that can be used as biological weapons. Currently we use anthrax exposure with antibiotics, but despite antibiotic use the mortality rate remains 75%. Antibiotics do not alter the detrimental effects of the anthrax toxin. Researchers from Rensselaer Polytechnic Institute (NY) and the University of Toronto reported recently their discovery of an anthrax toxin inhibitor that can neutralize the toxin. Using the same technique of placing multiple peptides on a liposome, these researchers also created a polyvalent inhibitor of cholera toxin. Therefore, the implication of this novel approach to design anthrax inhibitor (antitoxin) is not only valuable for the treatment of anthrax, but also because the same technique can be use to make better therapies against many other diseases such as cholera. Inhibitors designed in this fashion may one day be used together with standard antibiotic therapy to treat many diseases such as anthrax and cholera and others.
Analysis
The investigators created a fatty bubble (liposome) studded with small proteins that can bind tightly to the cell membrane receptor-binding protein used by anthrax toxin to gain entry into host cells. The investigators tested the anthrax inhibitor in rats. Given in small doses, the inhibitor given at the same time as the anthrax toxin prevented the animals from becoming ill. These experiments were the first to show the efficacy of a liposome-based polyvalent inhibitor in animals. The real test however, will come when the researchers test the action of their inhibitor in animals after infecting them with the bacteria that causes anthrax and allowing the disease process to start and examine the effect of the inhibitor given with antibiotics. Combining the toxin inhibitor with antibiotics may synergistically help the symptoms of anthrax. The study is important because the novel antitoxin design can be applicable to many other infectious diseases where a toxin leads to the major manifestations of the disease.
