Journal of Bacteriology & Parasitology

The anthrax capsule:Target for new vaccines and novel therapeutics

3^rd International Congress on Bacteriology and Infectious Diseases

August 04-06, 2015 Valencia, Spain

M Friedlander

Posters-Accepted Abstracts: J Bacteriol Parasitol

Abstract:

The polyglutamic acid capsule of Bacillus anthracis, the causative agent of anthrax is a well-established virulence factor,
conferring antiphagocytic properties on the bacillus. We have shown that the capsule released from the bacillus surface
may also contribute to virulence. In our research we have targeted the anthrax capsule for the development of medical
countermeasures, first using the capsule as a vaccine similar to successful efforts with other bacteria and secondly, by developing
a novel therapeutic against the capsule. Our experiments showed that a capsule vaccine is protective in the mouse model
and its efficacy could be enhanced by conjugation to a protein carrier. In initial experiments using high challenge doses, a
capsule conjugate vaccine was not protective in the rabbit but did show some protection in the nonhuman primate. Subsequent
experiments showed complete protection in the nonhuman primate against lethal aerosol challenge. This suggests the capsule
may be useful as an addition to a protective antigen-based vaccine. We are also developing the use of the B. anthracis capsuledepolymerizing
enzyme, CapD, as a therapeutic. We demonstrated that in vitro treatment of the encapsulated anthrax bacillus
with CapD enzymatically removed the capsule from the bacterial surface making it susceptible to phagocytic killing. Initial
experiments in vivo showed that CapD could be used successfully to treat experimental anthrax infections. Such a novel
approach to target the capsule virulence factor might be of value in the treatment of infections due to multidrug-resistant
strains.