Identifying a CXCL10 Chemokine Target in Bacillus anthracis Spores

Bacillus anthracis is a Gram-positive, rod shaped bacterium that is the causative agent of anthrax, a disease of rising concern for its potential use as a high risk bioterrorism agent. There are two forms of this bacterium: the spore which is the infectious form and the vegetative form that is responsible for the dissemination of the infection within the host. There are currently no therapeutic agents that target the spore form of B. anthracis. Chemokines are proteins that are secreted from a variety of cells that have an important role in the recruitment of the innate immune system response to an infected area of the body. Chemokines, specifically CXCL9, CXCL10, and CXCL11, have been shown to have an antimicrobial effect against both the spore and vegetative form of B. anthracis. This effect is similar to that of antimicrobial peptides against other bacterial species. In previous studies, CXCL10 has been shown to localize to the exosporium and spore coat-cortex interface. We conducted a transposon mutant library screen to identify potential targets of CXCL10 in B. anthracis spores.  The transposon mutant library was treated with CXCL10 for isolation of resistant spores which may have a disruption in a gene essential for CXCL10 susceptibility in B. anthracis spores. The disrupted genes are determined using PCR analysis and BLAST sequence identification. The identification of these disrupted genes will provide insight into bacterial targets essential in allowing CXCL10 to have its antimicrobial effect, providing a future therapeutic for a target against anthrax spores.