Figure 4.

Antigen presenting capacity and functional profile of splenic macrophages (Mφ) in vaccinated mice (± T. cruzi). Mice were vaccinated and challenged with T. cruzi trypomastigotes as in Figures 1, 2. (A,B) Splenocytes were labeled with fluorochrome-conjugated antibodies and analyzed by flow cytometry. Bar graphs show ex vivo percentages of the splenic Ly6G^loCD11b⁺ Mφ that exhibited surface expression of markers of maturation, antigen uptake, and antigen presentation (CD205⁺, CD209⁺, MHCI⁺, MHCII⁺, CD80⁺) in vaccinated (A) and vaccinated/infected (B) mice. (C–F) Splenic cells from vaccinated (C,D) and vaccinated/infected (E,F) mice were in vitro stimulated for 48 h in the presence of soluble T. cruzi lysate (TcL), and then labeled with fluorochrome-conjugated antibodies. Shown are the mean percentages of CD11b⁺ Mφ that responded to TcL stimulation with expression of markers of classical/proinflammatory (IL-1β^hi, TNF-α^hi) and alternative/immunomodulatory (CD200^hi, CD206^hi) phenotype. Splenic cells from non-vaccinated/non-infected and non-vaccinated/infected mice were used as controls. Data (mean ± SD) are representative of two independent experiments (n = 3 mice per group per experiment, duplicate observations per mouse), and significance is annotated as *none vs. vaccinated or infected vs. vaccinated/infected, and ^∧comparison of vaccinated groups (*,^∧p < 0.05, **,^∧∧p < 0.01, and ***,^∧∧∧p < 0.001).