Interleukin-17 mediates inflammatory tissue injury during orf development in goats.

Orf is an epithelial zoonotic infectious disease caused by orf virus (ORFV). Mounting studies have shown that IL-17-driven neutrophil inflammation plays a central role in inflammatory skin diseases. However, whether IL-17 plays a similar role and how does it work in the pathogenesis of orf is unclear. In this study, we found that during orf development, numerous inflammatory cells, especially neutrophils, infiltrated in the damaged lip tissue. Meanwhile, the production of IL-17 was increased in the lesion site. Further evidence showed that IL-17 potently stimulated the production of several chemokines that are crucial for neutrophil migration. In addition, IL-17 was mostly produced by CD4+ T cells and gamma delta T (γδ T) cells of the skin. In conclusion, the present study highlighted a critical role of IL-17-driven inflammation in the pathogenesis of orf and suggested that this cytokine may be a potential therapeutic target of this disease in goats.