Figure 7. Distinct migratory behavior and effector function of CD8⁺IFNγ⁺ and CD8⁺Pfn⁺ T-cells in T. cruzi infection.

(A) Experimental scheme of CD8⁺ cell isolation from noninfected naïve ifnγ ^−/− pfn ^+/+ and ifnγ ^+/+ pfn ^−/− donors, in vivo reconstitution of the CD8⁺ cell compartment of naïve cd8 ^−/− mice, infection with 100 bt of the Colombian strain at 15 days after cell transfer (dact) and analysis at 30 days post-infection. Parasitemia, survival rate, cardiac parasitism and CK-MB activity levels in the serum and colonization of the cardiac tissue by IFNγ⁺ and Pfn⁺ cells were evaluated. (B) Parasitemia and (C) survival curve of cd8 ^−/− mice non-reconstituted (NR) or reconstituted with CD8⁺ cells from ifnγ ^+/+ pfn ^−/− and ifnγ ^−/− pfn ^+/+ donors. In independent experiments, the animals were analyzed at 30 dpi when 100% of the mice in all the experimental groups were alive (arrow). (D) Number of amastigote nests in 100 microscopic fields of cardiac tissue sections. (E) Cardiomyocyte lesion evaluated by CK-MB activity in serum samples. The number of (F) IFNγ⁺ and (G) Pfn⁺ cells in 100 microscopic fields of cardiac tissue sections from mice non-reconstituted (NR) or reconstituted with CD8⁺ cells from ifnγ ^+/+ pfn ^−/− and ifnγ ^−/− pfn ^+/+ donors, at 30 dpi. Each symbol represents an individual mouse. These data represent three independent experiments. ^*, p<0.05; ^**, p<0.01; and ^***, p<0.001, comparing cd8 ^−/− infected mice non-reconstituted and reconstituted with CD8⁺ cells from ifnγ ^−/− pfn ^+/+ and ifnγ ^+/+ pfn ^−/− donors.