Bacteria might help protect military with new vaccines
YOKOTA AIR BASE, Japan — Military researchers studying radiation-resistant bacteria say they’ve discovered a faster way to make vaccines, which could help protect against biological warfare agents and pandemic infections.
The research could eventually lead to developing methods to help protect troops and others responding to nuclear disasters like last year’s meltdown in Fukushima, Japan.
A team of Uniformed Services University researchers who have been studying the radiation-resistant Deinococcus radiodurans bacterium published its findings in the scientific journal Cell Host and Microbe this month.
Deinococcus has been nicknamed “Conan the Bacterium,” and reportedly can withstand 3,000 times the dose of radiation it would take to kill a human. NASA has said the bacterium could even survive the bleak conditions on Mars.
USU pathology professor Michael Daly said his research team had worked out how the bacterium survives high doses of radiation.
“The key to its incredible resistance to radiation turns out to be manganese complexes within the cell that are amazingly protective of cellular proteins during irradiation,” he said. “Deinococcus has taught us something very important: If you want to survive radiation, protect your proteins.”
Daly and his team used that knowledge to create a vaccine.
Vaccines work by exposing people’s immune systems to dead or weakened versions of diseases so that they manufacture antibodies and become immune.
However, many ways of killing deadly bacteria and viruses — such as boiling them or exposing them to chemicals — destroy the proteins and surface structures that an immune system must be exposed to in order to generate antibodies, Daly said.
For their vaccine, the researchers bathed cells of the flesh-eating MRSA (methecillin-resistant Staphylococcus aureus) bacteria in Deinococcus manganese complexes and then gave them a massive dose of gamma radiation, he said.
The radiation destroyed the MRSA DNA, but its cell structures and proteins remained intact, thanks to the manganese complexes, Daly said.
The method developed by the USU team allows scientists to create a “3D hologram” of a bacterium or virus that includes all of the original proteins and structures needed to stimulate an immune response, but none of the genetic material such as DNA or RNA that would allow the disease to grow and make people sick, he said.
“That is the ideal vaccine,” Daly said. “It’s completely dead, but it appears to contain all the undamaged proteins that a mammalian immune system needs to create protective immunity.”
Scientists at the National Institutes of Health in Bethesda, Md., used a vaccine created using the method on mice, which became resistant to the disease.
“The finding was a breakthrough, as previous attempts at making an MRSA vaccine using conventional methods were unsuccessful,” Daly said. “There are many deadly diseases for which there are no vaccines. Top of the list would be HIV.”
The exciting thing about the new way of creating vaccines is its speed — a matter of months, rather than the years it can take to develop conventional vaccines using molecular biology, he said. The approach can be used on any pathogen that can be cultivated in the lab.
“Right now, it’s very difficult for the military or other health organizations to respond to new infections or emerging diseases in a timely way,” Daly said.
Pathogens can mutate quickly and can render older vaccines obsolete, which means that a way to rapidly produce new vaccines would be invaluable, Daly said.
The method developed by the USU researchers, who worked with colleagues from the NIH’s National Institute of Allergy and Infectious Diseases, also might be used to quickly manufacture vaccines to protect troops against biological warfare agents that might be employed by a rogue state or terrorists, he said.
An MRSA vaccine, for example, could be used to protect hospital workers, people with skin conditions or elderly people likely to spend a lot of time in hospitals where the disease is commonly contracted, he said.
A side benefit of the research into the Deinococcus manganese complexes could be new ways to protect soldiers and rescue workers from radiation during a nuclear disaster, such as the meltdown at the Fukushima Dai-ichi Nuclear Power Plant in Japan last year, Daly said.
Scientists now believe that protecting cell proteins might be even more important than protecting DNA from radiation. The manganese complexes may be able to mitigate some of the injuries suffered by people exposed to radiation.
They might also benefit people undergoing radiation therapy for cancer. For example, patients could potentially avoid hair loss by treating their scalps with manganese complexes prior to therapy, Daly said.
Army Capt. William Wilson, 26, of Denver — an environmental scientist who collected samples of soil, air and water to test for toxins during Operation Tomodachi — said the research sounded interesting, but added that he didn’t worry about radiation exposure during last year’s disaster.
“We had good testing equipment, and we were pretty confident of the results that we were getting,” which showed low levels of radiation in places where U.S. forces were working, he said.
Infectious disease physician Tilman A. Ruff, an associate professor at the University of Melbourne (Australia) Nossal Institute for Global Health, said the USU research looked promising. But he said additional studies by other research groups are needed to confirm their findings.
To date, no vaccines have been licensed in which radiation has been used to inactivate target organisms, Ruff said.
Daly said it will still take years for the first vaccine to be approved for humans using his methods. He said the approach needs to be tested on more animal models, and the Food and Drug Administration needs to approve its safety.
“While work to understand better how radiation causes mutations and how these effects might be reduced is certainly worthwhile, the primary maxim of prevention — minimizing the potential for exposure to ionizing radiation, from any source, as much as possible — remains the paramount priority in minimizing radiation-related health harm,” Ruff said.
The vaccine research was supported by the Air Force Office of Scientific Research, the Defense Threat Reduction Agency and the Intramural Research Program of the NIAID.