Bleach shows a feverlike fighting power
People have used bleach for more than 200 years to kill bacteria with only a limited understanding of how it carries out its sanitary mission. But new research suggests that its effects are very similar to those produced by a high fever.
The findings may increase our understanding of how the body fights off infections, in light of the fact that components of the immune system called neutrophils release high concentrations of hypochlorous acid, the active ingredient of bleach, in response to a bacterial infection.
“Hypochlorous acid is an important part of host defense,” said molecular biologist Ursula Jakob of the University of Michigan, lead author of a report that appeared Thursday in the journal Cell. “It’s not just something we use on our countertops.”
Jakob and her students did not set out to study bleach. They were looking at a bacterial protein called heat-shock protein 33, or Hsp33, a so-called molecular chaperon that protects proteins from stress, such as that caused by fevers.
At high temperatures, proteins unfold and clump together to form large, insoluble aggregates, similar to what happens when an egg is boiled. The aggregated proteins eventually lead to the cell’s death.
The Michigan team found that bleach did the same thing, causing proteins in both bacteria and human cells to unfold and aggregate.
“Many of the proteins that [bleach] attacks are essential for bacterial growth, so inactivating those proteins likely kills the bacteria,” said Marianne Ilbert, a postdoctoral fellow in Jakob’s lab.
And what does that have to do with Hsp33? The researchers found that bleach revs up the activity of the chaperon to protect the proteins.
“With Hsp33, bacteria have evolved a very clever system that directly senses the insult, responds to it and increases the bacteria’s resistance to bleach,” Jakob said.
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