Dialogue at the Skin: Commensal Bacteria Regulate T-Cell–Dendritic Cell Interactions

The skin microbiome has been comprehensively examined, but our understanding of how the microbiome shapes immune responses in the skin is still developing. To shed light on this relationship, Naik and colleagues studied mice in which specific commensal bacteria could be introduced and the effects on specific immune cells assessed.

Following the application of Staphylococcus epidermidis, they confirmed that IL-17– and interferon α–expressing CD8⁺ T cells accumulated in skin, peaking at 2 weeks and persisting for several months. While these cytokines regulate antiviral and inflammatory processes such as psoriasis, their buildup was not associated with inflammation. The authors then sought to identify how the buildup of T cells occurs. By using…