Various microorganisms that naturally colonise the skin may help protect us from infections as they trigger specific responses in the skin immune system to fight invasion by pathogens, a new research, involving an Indian-origin scientist, has found.
These microbes that colonise the skin are generally referred to as commensals.
Each type of microbe triggers unique aspects of the immune system, suggesting that immune cells found in the skin can rapidly sense and respond to changes in microbial communities, the findings showed.
“These findings reveal that the skin immune landscape is a highly dynamic environment that can be rapidly and specifically remodelled by encounters with defined commensals,” said Shruti Naik from Rockefeller University, New York.
“The findings have profound implications for our understanding of tissue-specific immunity and pathologies,” Naik added.
The researchers found that mice colonised with S. epidermidis were protected against infection with a disease-causing fungus.
This was because S. epidermidis increased the number of CD8+ T immune cells, which produced the chemical messenger IL-17A. Depleting CD8+ T cells or neutralising IL-17A removed this protective effect.
Dendritic cells, another type of immune cell, played a key role in generating this specific, non-inflammatory response.
The ability of different microbes to trigger distinct aspects of the immune system without causing inflammation opens the possibility of discovering new immune-boosting substances that may be added to vaccines or medications.
The findings appeared online in the journal Nature.
Shruti Naik, Nicolas Bouladoux, Jonathan L. Linehan, Seong-Ji Han, Oliver J. Harrison, Christoph Wilhelm, Sean Conlan, Sarah Himmelfarb, Allyson L. Byrd, Clayton Deming, Mariam Quinones, Jason M. Brenchley, Heidi H. Kong, Roxanne Tussiwand, Kenneth M. Murphy, Miriam Merad, Julia A. Segre, Yasmine Belkaid. Commensal-dendritic-cell interaction specifies a unique protective skin immune signature. Nature, 2015; DOI: 10.1038/nature14052