A researchersat the National Institutes of Health (NIH) has discovered that skin bacteria may help protect the body from infections. While immune cells are known to defend against harmful organisms, scientists have found that the millions of commensal bacteria living on the skin—collectively known as the skin microbiota—contribute to protective immunity. The study, published in Science on July 26, provides new insight into how skin bacteria interact with immune cells to enhance the body’s defenses.
Beneficial Skin Bacteria Strengthen Immune Response
To investigate the role of skin microbiota, researchers used germ-free mice—mice bred without any natural microbes in their gut or skin. The team colonized these mice with Staphylococcus epidermidis, a beneficial bacteria commonly found on human skin. They observed that this bacteria stimulated an immune cell in the skin to produce a molecule that helps protect against harmful microbes.
Colonized and non-colonized mice were exposed to a parasite to test this effect further. The results were striking: mice without S. epidermidis failed to mount an effective immune response. While those colonized with the bacteria showed a much more vigorous defense against infection.
Gut Microbiota Does Not Influence Skin Immunity
In a separate experiment, researchers explored whether bacteria in the gut played a role in skin immunity. They found that altering the gut microbiota did not impact the skin’s immune response. This indicate that the different tissues—such as the skin, gut, and lungs—have distinct microbiota that serve specific functions. These findings suggest that skin health depends on a unique balance of commensal bacteria that interact with immune cells at the skin’s surface.
Implications for Skin Disorders and Future Research
The authors believe these discoveries could have implications for understanding skin conditions such as eczema and psoriasis. If an imbalance in skin microbiota contributes to these diseases, future treatments might focus on beneficial bacterial communities to improve skin health. “Maintaining good health requires a diverse set of commensal bacteria in different tissues,” the researchers noted. “Further research is needed to determine whether disruptions influence skin disorders in the skin microbiota.”
The study was conducted by scientists from the National Institute of Allergy and Infectious Diseases. The National Human Genome Research Institute, and the National Cancer Institute—all components of the NIH. Their findings provide a new perspective on the relationship between the skin and the immune system. This offers potential pathways for future treatments and therapies.
Reference: S Naik et al. Compartmentalized control of skin immunity by resident commensals. Science, 2012
