Fig. 4: Inoculation of WT and DKO parasite lines in immuno-deficient mouse strains.

Both STAT-1^null (a) and STAT-4^null (b) mice were inoculated with WT and DKO cell-culture-derived metacyclic trypomastigotes (10⁵ parasite per IP inoculation per mouse) and followed for parasitemia (left panels), survival (middle panels). Data demonstrates that WT parasites increase in the blood over the course of infection until death between 15–16 days (for STAT-1^null animals) or between 31–89 days (in STAT-4^null animals). Inoculation of either mouse strain with DKO parasites does not lead to clinical disease. Only WT parasites, but not DKO-parasites, were found in tissues either by histopathologic analysis (as shown in heart sections of STAT-4^null animals in panel c) or in explantation culture of animals at 6 months post-infection (Table in Supplementary Fig. 9). Hpf, high powered field. This is a compilation of data from 3 separate experiments in the STAT-1^null mice and twice in the STAT-4^null mice, each with comparable results (5 mice per group in each experiment, n = 15 or 10, respectively). P < 0.05 in both Kaplan–Meier curves and in parasitemia analysis (2–3 mice per group per experiment, mean values and SD are shown for each timepoint).