Figure 1: Mice receiving rSSP4-primed CD4+CD25+ T cells but not mice receiving nonprimed CD4+CD25+ Tcells show exacerbation of acute T. cruzi infection and prolonged survival rate. (a) Histological examination by hematoxylin-eosin staining of cardiac tissue from untreated (w/o Tx), rSSP4 immunized, nonprimed- or rSSP4-primed-CD4+CD25+ T cells-transferred mice. Amastigotes nests are shown by arrow heads and inflammation foci with +. Magnification 40x. (b) Amastigotes nests area between different groups is calculated using Image J program. Graphs represent the average measure of 20 fields. (c) Percentage of inflammation foci was calculated considering the whole area in 20 fields using J program. Statistical analysis was done using Sigma Plot 10.0. (d) Parasitemia levels measured by direct parasite counting from blood samples. (e) Survival rate of infected mice. For (d) and (e), results are the average of three independent experiments; statistical analysis was done with GraphPad Prism 5.0.