Exposure and Activity Detection Assays for Anthrax Lethal Factor and Lethal Toxin

This CDC developed invention identifies an assay for extremely fast and sensitive detection of Bacillus anthracis lethal toxin (LTx), the toxin responsible for the lethal effects of anthrax infection. This assay has already been successfully tested in animals and will allow for early detection of anthrax exposure and screening of lethal factors to monitor anthrax toxicity, for example for vaccine trial candidates.

LTx is composed of two proteins, protective antigen (PA) and lethal factor (LF). In one scenario, the assay effectively detects LF by first using magnetic protein G beads to capture and concentrate LF in samples, then testing for LF on the bead by reacting it with a peptide substrate designed to mimic LF's natural target. By using techniques such as mass spectrometry, FRET or liquid chromatography, this test can check for LF rapidly and with extraordinary specificity and sensitivity. Methodology and basic assay validation have been confirmed in animals and naturally-exposed (by contaminated meat in a Bangladesh processing facility) human serum samples.