February 17, 2012
Circadian Rhythm Controls Immunity
Researchers are continuously learning how the body´s immune system is put together, and a recent discovery has found that the circadian clock may help determine the success of healing against pathogens in the body.
The study, published in the Cell Press journal Immunity, examined the function of Toll-like receptor 9 (TLR9), a protein in the immune system that detects the DNA of viruses and bacteria. The researchers found, according to a press release, that the circadian clock controlled TLR9 expression and function and that mice immunized when TLR9 was most responsive exhibited an enhanced immune response.In the mouse model that the researchers used, they found that the severity of sepsis depended on when the sepsis was introduced into the body, which correlated with the body´s cyclical changes in TLR9.
According to Dr. Erol Fikrig of Yale University School of Medicine, “These findings not only unveil a novel, direct molecular link between circadian rhythms and the immune system, but also open a new paradigm in the biology of the overall immune response with important implications for the prevention and treatment of disease. Furthermore, patients in the ICU often have disturbed sleep patterns, due to noise, nocturnal light exposure and medications; it will be important to investigate how these factors influence TLR9 expression levels and immune responses.”
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