Anthrax Research Today is a free monthly online journal that collates and summarizes the latest research about Anthrax, including details on bacillus anthracis, contagiousness, exposure, effects.

Detection and quantification of anthrax lethal factor in serum by mass spectrometry.

Boyer AE, Quinn CP, Woolfitt AR, Pirkle JL, McWilliams LG, Stamey KL, Bagarozzi DA, Hart JC, Barr JR

Centers for Disease Control and Prevention, National Center for Environmental Health, Division of Laboratory Sciences, 4770 Buford Highway, NE, Atlanta, Georgia 30341, USA.

The lethal toxin produced during Bacillus anthracis infection is a complex of protective antigen, which localizes the toxin to the cell receptor, and lethal factor (LF), a zinc-dependent endoproteinase whose known targets include five members of the mitogen-activated protein kinase kinase (MAPKK) family of response regulators. We have developed a method for detecting functional LF in serum. Anti-LF murine monoclonal antibodies immobilized on magnetic protein G beads were used to capture and concentrate the LF from serum. The captured LF was exposed to an optimized MAPKK-based peptide substrate, which it hydrolyzed into two smaller peptides. The LF cleavage products were then analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MS) and quantified by isotope dilution-MS. The entire analytical method can be performed in less than 4 h with detection of LF levels as low as 0.05 ng/mL. The method was used to quantify LF levels in serum from rhesus macaques infected with B. anthracis. Serum samples obtained at day 2 postinfection contained 30-250 ng/mL LF and illustrated the clear potential to detect LF earlier in the infection cycle. This method represents a highly specific and rapid diagnostic tool for early anthrax and has a potential additional role as a research tool for understanding toxemia and effects of medical countermeasures for anthrax.

Published 16 November 2007 in Anal Chem, 79(22): 8463-70.
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