Increase of IL-17-producing γδ cells following S. aureus challenge and reduced IL-17 induction in γδ T cells deficient mice. Total lung cells were isolated from naive or S.aureus-challenged mice at 6 h post-infection and IL-17 and IFN-γ producing γδ+ T cell were detected by intracellular staining. Cells were gated on CD3+ TCRαβ- TCRγδ+ cells. (A) The representative dot-plots were shown. Numbers indicate the percentages of IFN-γ+ cells (up panels) and IL-17+ cells (lower panels) among γδ T cells. (B) Absolute numbers of IFN-γ+ or IL-17+ γδ T cells in naive and 6 h post-infection lungs. (C) The representative dot plots showed the percentages of IL-17 producing cells in lung CD3+ T lymphocytes. Numbers in the quadrant indicate the percentage of cells. (D) IL-17A mRNA expression in the lungs following S. aureus challenge was determined by quantitative real-time PCR. Data are expressed as the mean ± SEM of 3–6 mice/time from three independent experiments. *p < 0.05 or **p < 0.01 versus WT mice.