A research team at the National Institutes of Health (NIH) has found that bacteria that normally live in the skin may help protect the body from infection. The millions of naturally occurring commensal bacteria in the skin are collectively known as the skin microbiota.
Using mouse models, the NIH team observed that commensals contribute to protective immunity by interacting with the immune cells in the skin.
The investigators colonized germ-free mice (mice bred with no naturally occurring microbes in the gut or skin) with the human skin commensal Staphylococcus epidermidis. The team observed that colonizing the mice with this one species of good bacteria enabled an immune cell in the mouse skin to produce a cell-signaling molecule needed to protect against harmful microbes. The researchers subsequently infected both colonized and non-colonized germ-free mice with a parasite. Mice that were not colonized with the bacteria did not mount an effective immune response to the parasite; mice that were colonized did.
The research paper is:
S Naik et al. Compartmentalized control of skin immunity by resident commensals. Science, 2012