Th1 and Th17 Immune Responses Act Complementarily to Optimally Control Superficial Dermatophytosis

Dermatophytoses are among the most common fungal infections worldwide, but little is known about the immune response in them. By comparing Trichophyton benhamiae acute superficial dermatophytosis in wild-type and Rag2^{-/-} mice, we showed that TCR-mediated immunity is critical for fungal clearance and clinical recovery. In WT mice, CD4^{+} T cells isolated from the skin-draining lymph nodes exhibit both T helper type (Th) 1 and Th17 differentiation during infection, with regard to produced cytokines or mRNA levels of transcription factors. Using IL-17A- and IFN-γ-deficient mice, we showed that IL-17A and IFN-γ are individually dispensable but together contribute to the optimal resolution of dermatophytosis. Furthermore, we generated and infected IL-17A and IFN-γ double-deficient mice and showed that both fungal clearance and clinical recovery were much lower in these mice than in single-deficient mice, suggesting the complementary roles of the two cytokines in dermatophytosis resolution. Thus, our data suggest that TCR-mediated immunity is critical for the optimal control of superficial dermatophytosis and that adaptive immunity is polarized to both Th1 and Th17 responses, with the Th17 antifungal response acting on dermatophyte clearance and the Th1 response being involved in both fungal clearance and Th17-inflammation down-modulation.