FIG 4.

Increased proinflammatory responses are induced in the spleen of T. cruzi-infected AhR KO mice. WT and AhR KO mice were infected with 1 × 10³ trypomastigotes. Spleens of T. cruzi-infected WT and AhR KO mice were processed and analyzed by ELISA and flow cytometry 10 days postinfection (dpi). (A to C) Ex vivo measurements by ELISA of IL-12p40 and IFN-γ levels were performed in supernatants of splenocytes cultured for 48 h (A and B, respectively). After extracellular and intracellular staining, cell numbers of the following cell populations were quantified by flow cytometry: CD11c⁺ CD8⁺ IL-12 p70⁺ and F4/80⁺ CD11b⁺ IL-12 p70⁺ (A); CD3⁺ CD4⁺ IFN-γ⁺ and CD3⁺ CD8⁺ IFN-γ⁺ (B); and CD11b⁺ F4/80⁺ ROS⁺ and CD11b⁺ F4/80⁺ iNOS⁺ (C). (D) Proportions of different T helper and regulatory cell populations Th1 (CD3⁺ CD4⁺ IFN-γ⁺), Th2 (CD3⁺ CD4⁺ IL-10⁺), Th17 (CD3⁺ CD4⁺ IL-17⁺), and Treg (CD3⁺ CD4⁺ CD25^hi Foxp3⁺). The results represent control uninfected (CO) mice and mice infected with T. cruzi (Tc) (A to C) or were normalized to the results determined for AhR KO and WT noninfected animals and represent fold change in panel D. Analyses were performed as comparisons between T. cruzi-infected WT mice and infected AhR KO mice. Data are presented as means ± SEM and represent results of three independent experiments performed with four animals each. ***, P < 0.001; **, P < 0.01; *, P < 0.05.