Although it is poisonous to humans at high doses, the heavy metal zinc, when taken in low doses, is used by the immune system to poison dangerous microbes, such as E. coli and those that cause tuberculosis, according to a new study published in the journal Cell Host & Microbe.
Researchers in France have found that immune cells are able to mobilize reserves of heavy metals to poison the microbes that make people sick. Although tests have so far only been done on zinc, the researchers believe other heavy metals, such as copper, may be used by the immune system in a similar fashion.
"The exact mechanism(s) of zinc penetration into the bacteria, and of bacterial killing by free zinc, still remains to be fully understood," explain the study authors. "Additional studies are required to improve our understanding of the role of zinc and other heavy metals in innate immunity to mycobacteria and other microbes…"
While the researchers work to better understand why heavy metals are so effective in killing bacterial microbes, the study has already led to the development of new vaccine strains against TB that are now being tested.