Protein expression pattern of murine macrophages treated with anthrax lethal toxin.

Anthrax lethal toxin (LeTx; a combination of protective antigen and lethal factor) secreted by the vegetative cells of Bacillus anthracis is cytotoxic for certain macrophage cell lines. The role of LeTx in mediating these effects is complicated largely due to the difficulty in identifying and assigning functions to the affected proteins. To analyze the protein profile of murine macrophages treated with LeTx, we employed two-dimensional polyacrylamide gel electrophoresis and MALDI-TOF MS, and interpreted the peptide mass fingerprint data relying on the ProFound database. Among the differentially expressed spots, cleaved mitogen-activated protein kinase kinase 1 acting as a negative element in the signal transduction pathway, and glucose-6-phosphate dehydrogenase playing a role in the protection of cells from hyperproduction of active oxygen were up-regulated in the LeTx-treated macrophages.