Ozone shuts down early immune response

Durham, N.C. -- A U.S. study in mice found ozone impairs the body’s first line of defense, making it more susceptible to subsequent foreign invaders, such as bacteria.

It has long been known that the air pollutant ozone is associated with increased cardiovascular and pulmonary hospitalizations and deaths, but the actual mechanisms involved remain unclear.

Duke University Medical Center pulmonary researchers in Durham, N.C., found that ozone exposure in mice at levels at approximating unhealthy levels for humans appears to enhance lung injury in response to bacterial toxins, but more importantly, it also appears to enhance programmed cell death in critical innate immune system cells that gobble up foreign invaders, keeping the airways clear.

"Small amounts of inhaled foreign material can be relatively harmless, since they stimulate an appropriate innate immune response that protects the lungs, lead author Dr. John Hollingsworth, a pulmonologist, said in a statement.

"However, it appears that ozone causes the innate immune system to overreact, killing key immune system cells, and possibly making the lung more susceptible to subsequent invaders, such as bacteria."

The findings are published in the Journal of Immunology.

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