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The bacteria that cause gingivitis manipulate our immune system
Last reviewed: 01.07.2025
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In a new study published in the Journal of Leukocyte Biology, scientists have discovered that Porphyromonas gingivalis bacteria, which cause a wide range of oral diseases from tooth decay to periodontitis, can manipulate the body's immune system, turning off normal defenses that could destroy them.
In particular, the experts found that the pathogenic bacteria Porphyromonas gingivalis provoke the production of anti-inflammatory molecules interleukin-10, which have the ability to suppress fever. This process, in turn, suppresses the function of T cells - the central regulators of the immune response, which control the duration and strength of the immune response.
"More than 50 percent of people in the United States over the age of 50 suffer from oral infections," said lead author Dr. Janette Katz, chair of pediatric dentistry at the University of Alabama at Birmingham. "We hope that our findings will help develop new treatments for chronic diseases caused by Porphyromonas gingivalis bacteria."
To conduct the experiment, the scientists used cells from mice that had been exposed to Porphyromonas gingivalis. Some of the cells were treated with inhibitory antibodies against interleukin-10, while others were left unprotected. All of the cells were then tested for the production of interferon-gamma, a protein secreted by the body's cells in response to a virus. An increase in interferon-gamma production was seen in the treated cells, but not in the untreated cells.
The findings suggest that the damage caused by Porphyromonas gingivalis bacteria occurs when the host's immune cells first encounter the pathogen, making it important that treatment be started as early as possible.
This study has revealed the mechanism by which Porphyromonas gingivalis bacteria causes chronic infection in the form of periodontal disease, and the scientists' experiment also provides insight into how the disease progresses.
"Gum disease and the infections that cause it are very difficult to treat," the researchers comment. "What has been unclear is why these infections are so difficult to eradicate. The new study suggests that these bacteria are not just evading our body's defenses, but are actually manipulating our immune system for their own survival."
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