Figure 1.

Paracoccidioides brasiliensis infection increases the in vitro and in vivo IL-17A production. (A,B) Splenocytes from C57BL/6 mice were isolated and cultivated (1 × 10⁶) in the presence of or not of viable virulent yeast strain 18 of P. brasiliensis (Pb18) during 5 days (multiplicity of infection of 1). (A) The frequency of IL-17A⁺-producing cells and (B) Th17 (CD4⁺IL-17A⁺) cells was determined by flow cytometry. (C–E) C57BL/6 mice were infected with 1 × 10⁶ Pb18 yeast cells (intravenously). (C) The level of IL-17A was measured by enzyme-linked immunosorbent assay in the whole lung homogenate after 30 days postinfection (dpi). (D) The frequency of IL-17A-producing cells was evaluated in the lungs from uninfected and infected (30 dpi) mice. (E–G) The frequency of natural killer (CD49b⁺IL-17A⁺), Tγδ (γδ⁺IL-17A⁺), B (CD19⁺IL-17A⁺), IL-17-producing CD8⁺ T (CD8⁺IL-17A⁺), and Th17 cells was assessed in the lungs after 30 dpi. (E) Cells were analyzed inside the IL-17-positive gate. (F) Lymphocytes were gated inside the singlet population. One representative mice is shown. (G) Absolute number (bars) and mean percentage (above bars) of each IL-17-producing cell population gated inside lymphocytes. Bars represent the mean ± SEM of 5 mice. *p < 0.05 compared to non-infected control. Similar results were obtained in three independent experiments.