Binding and Neutralization of Bacillus Anthracis Protective Antigen Toxin and its Complexes using Glycoconjugates

摘要

Bacillus genus species are important since they are responsible for food-borne illnesses and food spoilage problems . Additionally, Bacillus anthracis species are considered potential biological warfare and bioterrorism agents . Once B. anthracis spores germinate into vegetative cells within a host, they produce toxins known as protective antigen (PA), edema factor (EF), and lethal factor (LF) that diminish macrophage capacity to kill the bacteria and reduce host resistance to infection . B. anthracis PA83 binds to an appropriate cell membrane receptor and is then cleaved into PA_(63) and PA_(20) . The latter is released into the extracellular fluid while PA_(63) forms a pore and transports EF and LF into the cytosol of the cell . Glycoconjugates are complex molecules that have had numerous applications in the biomedical and pharmaceutical fields. They are involved in numerous biological processes including binding, cell-cell recognition, and cell-cell interactions . Glycoconjugates are defined as organic molecules containing carbohydrate bound to either a lipid or a protein or other molecular entities . We previously reported that glycoconjugates contribute to the binding, recognition1, inhibition, and destruction of bacterial spores . The aim of the present study was to determine if glycoconjugates recognize and bind PA83 toxin, its PA_(63) or PA_(20) fractions, or all of them. Additionally, macrophages were exploited as glycoconjugate targets to recognize and neutralize the PA-EF-LF, PA-EF, and PA-LF complexes. More specifically, murine peritoneal macrophages were measured for phagocytosis, cell morphology, direct microscopic counts, trypan blue stain, macrophage viability, and nitric oxide (NO) production.