Is it possible to reverse the effects of a life-threatening poison? In the case of one such toxic substance, it very well may be.

A recent study at the Tulane National Primate Research Center (TNPRC) showed for the first time that an experimental drug can save nonhuman primates exposed to deadly ricin toxin. Ricin is derived from the seeds of the castor oil plant, and a single dose of purified ricin powder the size of a few grains of table salt can kill an adult. Due to its toxicity and the availability of its source material, it is considered a leading bioterrorism threat.

It’s also difficult to counter the effects of the lethal toxin once a person has been exposed to it.

“Clinically, there is no treatment that can be administered currently to save someone in the event of an exposure to this toxin,” said study first author Chad Roy, PhD, director of infectious disease aerobiology and biodefense research programs at TNPRC.

In the study, researchers at TNPRC, Mapp Biopharmaceutical Inc., University of Texas Southwestern Medical Center and the New York State Department of Health used a drug comprised of humanized monoclonal antibodies against the toxin. This drug was developed from research of a successful ricin vaccine that was originally tested at TNPRC, and it was engineered to look very similar to the structure of antibodies that were generated from vaccinated nonhuman primates.

“Our study shows proof of concept in a near-clinical animal model, the nonhuman primate, that we finally have a life-saving treatment against one of the world’s most notorious toxin agents,” noted Roy.

Researchers also found the drug was much more effective four hours after exposure as opposed to 12 hours after exposure, indicating a short time window for successful treatment. They plan to develop a stronger version that would “expand the therapeutic window” for effective treatment longer after exposure, Roy said.

Additionally, the scientists hope to develop the drug as a possible preventative therapeutic that emergency workers or members of the military could take before they enter areas contaminated with ricin. The research is part of ongoing federal efforts to develop effective countermeasures against bioterrorism agents.

Reviewed: June 2020

According to the Center for Disease Control and Prevention, more than 1.1 million people in the United States are living with an HIV infection. In the United States, Louisiana has the third-highest rate of people with an HIV infection and AIDS cases. In 2015, Louisiana-based Tulane National Primate Research Center (TNPRC) was awarded $4.2 million to study new ways to flush out and kill HIV from reservoirs in the body where the virus lurks beyond the reach of antiviral therapy options.

Current HIV treatment options can stop the disease from progressing to AIDS and knock the virus down to “undetectable” levels in the bloodstream, but they fall short of an HIV cure because they must be taken for life to keep the disease in check. That’s because HIV integrates into the genome of memory T-cells and lies dormant in reservoirs throughout the body. If a patient stops taking antivirals, HIV reawakens from these reservoirs to resume its attack on the immune system.

“The major obstacle to a cure for HIV infection is how to purge the persistent reservoir of latently infected cells,” said lead researcher Dr. Huanbin Xu, assistant professor of pathology.

Using a nonhuman primate research model of HIV, Dr. Xu plans to test standard antiviral drugs with a combination of therapies to wake up the latent virus and trigger the immune system to recognize infected cells and attack them. He will then target any remaining virus with an antibody drug conjugate, a new class of highly potent biopharmaceutical drugs. The so-called “kick and kill” approach to activate latent HIV so it’s more susceptible to targeted treatments is a promising new frontier in the search for a possible cure, Xu says.

His team will also test a new gene editing approach with a targeted delivery system for the therapy tailored to an individual’s immune system.

“So far, it’s a novel, comprehensive strategy,” Dr. Xu says.

One of the advantages of using a primate research model for the treatment is that, if it’s successful, human clinical trials could begin relatively quickly, Dr. Xu says.

Reviewed: June 2020