A New Study Found that Anthrax Toxin Could be Used as a Pain-blocking Treatment

Pain is a normal defense mechanism that alerts the body of potential damage to prevent further injury. A painful stimulus causes sensitivity, which triggers the transmission of pain signals, via afferent sensory nerve fibers, to the dorsal horn of the spinal cord and up into the brain. Pain information then travels from the brain through the spinal cord to our organs and limbs. 

Pain is an enormous problem globally. Estimates suggest that 20% of adults suffer from pain globally and 10% are newly diagnosed with chronic pain each year. Nevertheless, the problem of pain has primarily been regarded as a medical problem and has been little addressed by the field of public health.

Pain can be divided into acute when it is sudden and may resolve without long-term consequences and chronic when it lasts longer than 3 months. 

A report from the Centers for Disease Control and Prevention (CDC) estimates that about one-fifth of adults in the United States had chronic pain in 2016 — and 8% of this group had pain that frequently limited work, social, recreational, and self-care activities.

New Study Results

A recent study published in the journal Nature Neuroscience found that anthrax toxin may selectively target pain neurons and alter the pain response in mice. 

Dr. Isaac Chiu, an associate professor of immunobiology at Harvard Medical School, in Boston, and the senior author of the new study, set out with a team to learn about the connection between microbes and pain.

As part of the new investigation, experiments to detect gene expression with RNA scope analysis in mouse and human sensory nerves in the dorsal root ganglia (DRG) demonstrated that these pain fibers had anthrax toxin receptor 2, which were not present in other central nervous system neurons.

Anthrax bacteria produce three proteins: protective antigen (PA), edema factor (EF), and lethal factor (LF). PA and EF together are referred to as “edema toxin” (ET).

The researchers then administered anthrax LF or ET to DRG cultures and observed changes in signaling within cells.

After confirming the effects of anthrax toxin in cells, the researchers conducted experiments in mice to explore the impact on pain sensation. Mice received injections of LF and EF with and without PA via the spinal canal.

Researchers found that administering ET to mice decreased their ability to sense heat, cold, and pinpricks without affecting their heart rate, body temperature, or motor coordination.

The researchers also administered ET by injection to mice with artificially induced inflammatory or neuropathic pain. The researchers found that ET reduced neuropathic and inflammatory pain responses in mice. They also administered ET combined with botulinum toxin and found that it also blocked pain in mice.

The researchers believe that their results may lead to the development of new pain therapeutics. Future animal and human studies are needed to determine the safety and efficacy of the approach but their results are promising. 


Lori Uildriks (2021, Dec 22). Deadly anthrax toxin: A pain-blocking treatment of the future? Medical News Today. Retrieved from: 


Goldberg DS, McGee SJ. Pain as a global public health priority. BMC Public Health. 2011;11:770. Published 2011 Oct 6. doi:10.1186/1471-2458-11-770 

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