Radiation-resistant bacterium could be key to faster, safer, more cost-effective vaccine production

By Zachary Willis

Improved and more cost-effective vaccines could be on the horizon thanks to a strain of bacteria and the efforts of USU faculty member, Dr. Michael Daly. A chief expert of this widespread microorganism, Daly has spent decades studying Deinococcus radiodurans and the fascinating way it has been able to thrive in adverse settings across the planet.

What makes D. radiodurans so environmentally robust? It can be found in highly radioactive waste sites leftover from the Cold War, frozen in Antarctic ice, and dried in deserts soils, evolving to withstand radiation, corrosive chemicals, and the most adverse of climates. Daly goes on to explain, “the answer is, Deinococcus cells accumulate manganese-based antioxidant complexes that substantially reduce the level of radiation damage to its DNA repair enzymes and other proteins needed to rebuild the cell.”

“When thinking of a cell, imagine a computer,” Daly explains. “There’s hardware (proteins) and software (genes). When genes are broken by radiation, repair enzymes need to stitch DNA back together again, or the cell will die, but enzymes are damaged by radiation, too. Deinococcus has taught us that if you want to survive a lot of radiation, you are much better off protecting your proteins than your DNA.”

With the major mysteries of D. radiodurans seemingly solved, further studies into the practical applications of its manganese antioxidants have been left to the few dedicated remaining researchers, like Daly, who realized that the radiation-resistant strain could be the key to creating vaccines that would be faster to produce, more cost-effective, and potentially safer. 

In some ways, the field of Deinococcus research became a victim of its own success. 

“On the one hand, we showed that a genome sequence cannot predict radiation resistance,” Daly says. “And on the other, we demonstrated that proteins (not DNA) are the critical targets in irradiated cells. Today, it is impressive advances in proteomics that herald the next Deinococcus breakthroughs -- towards the development of improved radioprotectors needed to safely get astronauts to Mars and back, and towards even better irradiated vaccines.”

While further research is needed, Daly and his team have already harnessed the bacteria’s protective properties to fast-track vaccine production by cutting down the amount of trial and error necessary to determine the proteins needed to mount a protective immune response, by protecting the critical epitopes of radiation-inactivated pathogens with those manganese antioxidants.

Pathology Professor Dr. Michael Daly holds a petri dish containing Deinococcus radiodurans, a bacterium famous for its
extreme resistance to radiation that may hold the key to faster vaccine development. (Photo by Helen Hocknell)

“Historically, the discovery and commercial development of a licensed lead vaccine candidate has often taken decades of basic research followed by years of pre-clinical and clinical development,” Daly explains. “Recent experiences with emerging pathogens, including MERS, Ebola, and now SARS-CoV-2, have spurred the DoD to develop vaccines much faster. Due to the significantly greater time required for the discovery and testing of a conventional subunit vaccine, the use of radiation-inactivated whole pathogen preparations currently represent the most cost-effective platform for the speedy deployment of highly protective vaccines against viruses and bacteria.”