Accelerating countermeasure candidate discovery for A-series chemical warfare agent exposure

Area of Science:

• Biochemistry
• Toxicology
• Analytical Chemistry

Background:

• A-series chemical warfare agents (CWAs) pose a growing threat.
• Traditional oxime countermeasures may have limitations against novel CWAs.
• Understanding A-series CWA inhibition of human acetylcholinesterase (hAChE) is critical.

Purpose of the Study:

• To characterize the inhibition kinetics of A-series CWAs on hAChE.
• To evaluate the efficacy of oximes in reactivating A-series-adducted hAChE.
• To demonstrate the utility of high-throughput mass spectrometry (HT-MS) in toxic chemical characterization.

Main Methods:

• Utilized high-throughput (HT) mass spectrometry (MS) technologies.
• Performed label-free quantitation of enzyme inhibition and reactivation.
• Characterized kinetics at rates up to 7,000 reactions per hour.

Main Results:

• A-series agents demonstrated inhibitory potencies comparable to established CWAs (sarin, VX).
• Bipyridinium-based oximes successfully reactivated A-series-adducted hAChE in vitro.
• HT-MS enabled rapid and safe characterization of A-series CWA interactions with hAChE.

Conclusions:

• A-series CWAs represent a significant toxicological challenge.
• Bipyridinium oximes show promise as countermeasures against A-series CWAs.
• HT-MS is a powerful tool for evaluating emerging chemical threats and countermeasures.