Because of the highly fatal nature of pulmonary anthrax, the ease of production and storage of the spores of B. anthracis, and their survival in the environment after an attack, this bacterium has become the primary agent in biowarfare and bioterrorism. The window of opportunity for effective antibiotic treatment of patients with pulmonary anthrax is so small that vaccination is the current best defense against the disease. The spore of B. anthracis is the actual infectious agent and the form of the organism that is involved with the first interactions with the host macrophages. Recent studies have found that spore antigens are an important component to immunity against anthrax. We have identified a unique carbohydrate component of the spore. It is not known what roles carbohydrates play in the biology of the spore, from any species of bacteria. In this project, we will create mutants, which deleted for B. anthracis spore glycoprotein genes. The effect of these gene knockouts on spore carbohydrate content will be determined by mass spectrometry. The mutant cells will be evaluated for defects in spore formation and the spores from these mutants characterized for their resistance properties and germination efficiency in vitro. The role of the carbohydrate and protein components of the exosporium glycoprotein in conferring immunity to infection will be assessed. Preliminary experiments will be carried out to determine if loss of the BclA glycoprotein of B. anthracis affects the virulence properties of this anthrax agent. These studies will provide the information to evaluate whether the spore carbohydrate would be useful as an immunogen in a vaccine against anthrax. The results will provide supporting data for a future proposal to more specifically correlate spore surface structures with virulence and as vaccine targets.
