Abstract
Staphylococcus aureus is a major cause of skin and soft tissue infections and aggravator of the inflammatory skin disease atopic dermatitis (AD). Epicutaneous exposure to S. aureus induces Th17 responses through skin Langerhans cells (LCs), which paradoxically contribute to host defense but also to AD pathogenesis. The underlying molecular mechanisms of the association between S. aureus and skin inflammation are poorly understood. Here, we demonstrate that human LCs directly interact with S. aureus through the pattern-recognition receptor langerin (CD207). Human, but not mouse, langerin interacts with S. aureus through the conserved β-N-acetylglucosamine (GlcNAc) modifications on wall teichoic acid (WTA), thereby discriminating S. aureus from other staphylococcal species. Importantly, the specific S. aureus WTA glycoprofile strongly influences the level of Th1-and Th17-polarizing cytokines that are produced by in vitro generated LCs. Finally, in a murine epicutaneous infection model, S. aureus induced a more pronounced influx of inflammatory cells and pro-inflammatory cytokine transcripts in skin of human langerin transgenic mice compared to wild-type mice. Our findings provide molecular insight into the unique pro-inflammatory capacities of S. aureus in relation to inflammatory skin disease.
