The activation status and accumulation of T. cruzi-specific T cells was related to parasite antigen abundance in the chronically infected tissues, as shown by the fact that CD69 expression was decreased in the case of infection with the low level persistent TCC strain (Fig 1D and 1E) and in mice treated with a non-curative course of the trypanocidal compound benznidazole (BZ) (Fig 1F). Here, CD69 is linked to infection.