A research team at NIH, including Heidi Kong, M.D., at NCI, has found that bacteria that normally live in the skin may help protect the body from infection. As the largest organ of the body, the skin represents a major site of interaction with microbes in the environment. Although immune cells in the skin protect against harmful organisms, until now, it has not been known if the millions of naturally occurring—and normally harmless—commensal bacteria in the skin, collectively known as the skin microbiota, also have a beneficial role. Using mouse models, the NIH team observed that commensals contribute to protective immunity by interacting with the immune cells in the skin. Their findings appeared online July 26, 2012, in Science and have significance for cancer patients whose immunity may be compromised.
In separate experiments, the team sought to determine if the presence or absence of commensals in the gut played a role in skin immunity. They observed that adding or eliminating beneficial bacteria in the gut did not affect the immune response at the skin. These findings indicate that microbiota found in different tissues—skin, gut, lung—have unique roles at each site and that maintaining good health requires the presence of several different sets of commensal communities. This study provides new insights into the protective role of skin commensals and demonstrates that skin health relies on the interaction of commensals and immune cells.
The study was led by investigators in the laboratories of Yasmine Belkaid, Ph.D., at the National Institute of Allergy and Infectious Diseases, in collaboration with Julie Segre, Ph.D., at the National Human Genome Research Institute, and Giorgio Trinchieri, M.D., and Kong at the National Cancer Institute.